feat(billing): B-2.7 Stripe Checkout 3 plans CAD/TVQ + Apple/Google Pay

Adds the customer-facing checkout flow under /checkout/<plan>:
- src/billing/plans.py — Plan dataclass + 3 plans (DictIA 8 / 16 / Cloud),
  monthly + yearly Price IDs resolved from STRIPE_DICTIA_*_{SETUP,MONTHLY,YEARLY} env.
- src/billing/stripe_client.py — lazy stripe.api_key init, get_or_create_customer
  (persists user.stripe_customer_id), create_checkout_session with mode=subscription,
  currency=cad, automatic_tax=true (TPS 5% + TVQ 9.975%), billing_address_collection,
  metadata on both Session and Subscription for the B-2.8 webhook.
- src/billing/routes.py — GET /checkout/<plan>?period=monthly|yearly returns 303
  redirect to Stripe-hosted Checkout. Friendly French flash + redirect to /tarifs
  on unknown plan, missing STRIPE_SECRET_KEY, missing Price IDs, or Stripe API error.
  GET /checkout/success and /checkout/cancel render brand-tokenized templates that
  extend marketing/base.html.
- templates/billing/{success,cancel}.html — explicit "activé sous quelques minutes"
  note (webhook is async), aucun montant prélevé reassurance on cancel.
- config/env.stripe.example — env vars + Stripe Dashboard setup checklist
  (CAD activation, Stripe Tax registrations, Apple/Google Pay enable, webhook).
- tests/test_stripe_checkout.py — 25 tests covering plans, stripe_client, routes,
  and the _PUBLIC_INDEXABLE_ENDPOINTS integration. Stripe SDK mocked via
  unittest.mock.patch (no network). Windows manual driver included.

Webhook (B-2.8) will be the source of truth for user.subscription_status.
This task only mutates user.stripe_customer_id (identity, not state).
Existing pricing CTAs in templates/marketing/_partials/_pricing_tiers.html
already link to /checkout/<slug> (verified) — no marketing template touched.

Tests: 25/25 new + 89/89 prior pass on Windows manual driver.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

config/env.stripe.example

@@ -0,0 +1,68 @@
+###############################################################################
+# Stripe — Checkout + Subscriptions (B-2.7 / B-2.8)
+###############################################################################
+#
+# Required for the /checkout/<plan> flow and the /webhooks/stripe receiver.
+# The application will boot without these — billing routes will redirect to
+# /tarifs with a "contact info@dictia.ca" message until the keys are set.
+#
+# Get these from https://dashboard.stripe.com (CAD account)
+# - Use sk_test_/pk_test_/whsec_test_ keys against the Stripe test mode for
+#   pre-prod. Switch to live keys ONLY after end-to-end CAD/TVQ rehearsal.
+
+# STRIPE_SECRET_KEY=sk_test_...                     # or sk_live_...
+# STRIPE_PUBLISHABLE_KEY=pk_test_...                # used client-side; not strictly needed for hosted Checkout
+# STRIPE_WEBHOOK_SECRET=whsec_...                   # for B-2.8 webhook signature verification
+
+###############################################################################
+# Price IDs — one per plan, period, and (for hardware plans) setup fee.
+###############################################################################
+#
+# Format: price_xxxxxxxxxxxxxxxxxxxxxxxxxx
+# Naming convention in this codebase: STRIPE_<PLAN>_<TYPE>
+#   PLAN  = DICTIA_8 | DICTIA_16 | DICTIA_CLOUD
+#   TYPE  = SETUP (one-time, hardware only) | MONTHLY | YEARLY
+#
+# Yearly Price = Monthly Price × 12 × 0.85 (15 % discount). Configure both
+# Prices in the Stripe Dashboard for each plan.
+
+# DictIA 8 (8-channel hardware bundle): 3 450 $ setup + 173 $/mo
+# STRIPE_DICTIA_8_SETUP=price_xxx
+# STRIPE_DICTIA_8_MONTHLY=price_xxx
+# STRIPE_DICTIA_8_YEARLY=price_xxx
+
+# DictIA 16 (16-channel hardware bundle): 5 750 $ setup + 201 $/mo
+# STRIPE_DICTIA_16_SETUP=price_xxx
+# STRIPE_DICTIA_16_MONTHLY=price_xxx
+# STRIPE_DICTIA_16_YEARLY=price_xxx
+
+# DictIA Cloud (SaaS-only, no hardware): 369 $/mo
+# STRIPE_DICTIA_CLOUD_MONTHLY=price_xxx
+# STRIPE_DICTIA_CLOUD_YEARLY=price_xxx
+
+###############################################################################
+# Required Stripe Dashboard configuration
+###############################################################################
+#
+# 1. Activate CAD currency on the account (Settings → Account → Currencies).
+#
+# 2. Enable Stripe Tax with TPS (5 %) and TVQ (9.975 %) for Quebec
+#    (Tax → Settings → Tax registrations → Canada → Quebec).
+#    All Checkout Sessions are created with `automatic_tax: { enabled: true }`
+#    and `billing_address_collection: required` so Stripe computes taxes.
+#
+# 3. Enable Apple Pay + Google Pay
+#    (Settings → Payment methods → Apple Pay, Google Pay).
+#    Apple Pay requires verifying the dictia.ca domain via the Stripe-hosted
+#    `.well-known/apple-developer-merchantid-domain-association` file.
+#
+# 4. For each plan, create:
+#    - One recurring monthly Price (CAD, billing_scheme=per_unit)
+#    - One recurring yearly Price (CAD, = monthly × 12 × 0.85)
+#    For DictIA 8 and DictIA 16, also create a one-time Price for the setup fee.
+#
+# 5. Create a webhook endpoint (B-2.8) pointing at https://dictia.ca/webhooks/stripe
+#    with at least the events: checkout.session.completed,
+#    customer.subscription.created, customer.subscription.updated,
+#    customer.subscription.deleted, invoice.payment_failed.
+#    Copy the signing secret into STRIPE_WEBHOOK_SECRET above.

src/billing/__init__.py

@@ -8,10 +8,17 @@ Routes added in Tasks B-2.7 (checkout) and B-2.8 (webhook).
 """
 from flask import Blueprint
 
+# template_folder points at the project-level `templates/` so render_template
+# can resolve names like 'billing/success.html' the same way the marketing
+# and legal blueprints resolve 'marketing/...' / 'legal/...'.
 billing_bp = Blueprint(
     'billing',
     __name__,
     url_prefix='/checkout',
-    template_folder='../../templates/billing',
+    template_folder='../../templates',
     static_folder=None,
 )
+
+# Import routes to register them on billing_bp. Must come after blueprint
+# instantiation. Keep the # noqa comments — these guards exist for ruff/flake8.
+from src.billing import routes  # noqa: E402, F401

src/billing/plans.py

@@ -0,0 +1,97 @@
+"""DictIA pricing plans (B-2.7).
+
+Centralized plan registry. Stripe Price IDs are resolved from environment
+variables — set STRIPE_<PLAN>_<PERIOD> env vars in production. The slug
+(`dictia-8`, `dictia-16`, `dictia-cloud`) is the canonical identifier
+used throughout the codebase (URL params, webhook metadata, audit logs).
+
+Pricing reference (CAD, pre-tax — TPS/TVQ added by Stripe automatic_tax):
+- DictIA 8:    3 450$ setup (one-time) + 173$/mo recurring (or yearly = 173 × 12 × 0.85)
+- DictIA 16:   5 750$ setup (one-time) + 201$/mo recurring (or yearly = 201 × 12 × 0.85)
+- DictIA Cloud:                          369$/mo recurring (or yearly = 369 × 12 × 0.85)
+"""
+import os
+from dataclasses import dataclass
+from typing import Dict, List, Optional
+
+
+@dataclass(frozen=True)
+class Plan:
+    """A DictIA subscription plan.
+
+    Stripe Price IDs are resolved lazily from environment variables — the
+    Plan instance itself only stores the variable names. This lets the
+    application boot without Stripe credentials (CI, dev branches) and
+    keeps secrets out of source control.
+    """
+    slug: str
+    name: str
+    description_fr: str
+    has_setup_fee: bool
+    monthly_env: str
+    yearly_env: str
+    setup_env: Optional[str] = None  # only set for plans with a setup fee
+
+    def setup_price_id(self) -> Optional[str]:
+        if not self.has_setup_fee or not self.setup_env:
+            return None
+        return os.environ.get(self.setup_env)
+
+    def monthly_price_id(self) -> Optional[str]:
+        return os.environ.get(self.monthly_env)
+
+    def yearly_price_id(self) -> Optional[str]:
+        return os.environ.get(self.yearly_env)
+
+    def is_configured(self) -> bool:
+        """True when all required Stripe Price IDs are set in the environment."""
+        if self.has_setup_fee and not self.setup_price_id():
+            return False
+        return bool(self.monthly_price_id() and self.yearly_price_id())
+
+    def price_id_for_period(self, period: str) -> Optional[str]:
+        return self.yearly_price_id() if period == 'yearly' else self.monthly_price_id()
+
+
+PLANS: Dict[str, Plan] = {
+    'dictia-8': Plan(
+        slug='dictia-8',
+        name='DictIA 8',
+        description_fr='Boîtier 8 canaux + transcription IA locale (poste de travail).',
+        has_setup_fee=True,
+        setup_env='STRIPE_DICTIA_8_SETUP',
+        monthly_env='STRIPE_DICTIA_8_MONTHLY',
+        yearly_env='STRIPE_DICTIA_8_YEARLY',
+    ),
+    'dictia-16': Plan(
+        slug='dictia-16',
+        name='DictIA 16',
+        description_fr='Boîtier 16 canaux + transcription IA locale (salle de réunion).',
+        has_setup_fee=True,
+        setup_env='STRIPE_DICTIA_16_SETUP',
+        monthly_env='STRIPE_DICTIA_16_MONTHLY',
+        yearly_env='STRIPE_DICTIA_16_YEARLY',
+    ),
+    'dictia-cloud': Plan(
+        slug='dictia-cloud',
+        name='DictIA Cloud',
+        description_fr='Transcription IA hébergée au Québec, 100% conforme Loi 25.',
+        has_setup_fee=False,
+        monthly_env='STRIPE_DICTIA_CLOUD_MONTHLY',
+        yearly_env='STRIPE_DICTIA_CLOUD_YEARLY',
+    ),
+}
+
+VALID_PERIODS = ('monthly', 'yearly')
+
+
+def get_plan(slug: str) -> Optional[Plan]:
+    """Return the Plan for `slug`, or None if unknown."""
+    if not slug:
+        return None
+    return PLANS.get(slug)
+
+
+def list_plans() -> List[Plan]:
+    """Return all registered plans in registration order."""
+    return list(PLANS.values())

src/billing/routes.py

@@ -0,0 +1,126 @@
+"""Billing routes — Stripe Checkout (B-2.7).
+
+URL space (prefix `/checkout`, set on billing_bp):
+- GET  /checkout/<plan>?period=monthly|yearly  → 303 redirect to Stripe-hosted Checkout
+- GET  /checkout/success?session_id=...        → confirmation page (async activation note)
+- GET  /checkout/cancel                        → friendly "no charge made" page
+
+The webhook route (B-2.8) is registered separately at /webhooks/stripe outside
+the /checkout prefix and is CSRF-exempt.
+"""
+import logging
+
+from flask import (
+    Blueprint, current_app, flash, redirect, render_template,
+    request, url_for,
+)
+from flask_login import current_user, login_required
+
+from src.billing import billing_bp
+from src.billing.plans import VALID_PERIODS, get_plan
+from src.billing.stripe_client import (
+    StripeNotConfiguredError,
+    create_checkout_session,
+    is_stripe_configured,
+)
+
+logger = logging.getLogger(__name__)
+
+
+@billing_bp.route('/<plan>')
+@login_required
+def checkout(plan):
+    """Initiate Stripe Checkout for the given plan + period.
+
+    Redirects to /tarifs with a French flash on any error (unknown plan,
+    Stripe not configured, plan Price IDs missing, Stripe API failure).
+    Returns a 303 See Other redirect to the Stripe-hosted Checkout on success
+    (303 is what Stripe documents for HTTP redirects to checkout.stripe.com).
+    """
+    plan_obj = get_plan(plan)
+    if plan_obj is None:
+        flash('Forfait inconnu.', 'danger')
+        return redirect(url_for('marketing.tarifs'))
+
+    period = request.args.get('period', 'monthly')
+    if period not in VALID_PERIODS:
+        period = 'monthly'
+
+    if not is_stripe_configured():
+        flash(
+            "Le paiement en ligne n'est pas disponible pour le moment. "
+            "Contactez info@dictia.ca pour finaliser votre abonnement.",
+            'warning',
+        )
+        return redirect(url_for('marketing.tarifs'))
+
+    if not plan_obj.is_configured():
+        flash(
+            "Ce forfait n'est pas encore configuré. Contactez info@dictia.ca.",
+            'warning',
+        )
+        return redirect(url_for('marketing.tarifs'))
+
+    success_url = url_for('billing.success', _external=True)
+    cancel_url = url_for('billing.cancel', _external=True)
+
+    try:
+        session = create_checkout_session(
+            plan_slug=plan,
+            period=period,
+            user=current_user,
+            success_url=success_url,
+            cancel_url=cancel_url,
+        )
+    except StripeNotConfiguredError as e:
+        logger.error('Stripe not configured at checkout: %s', e)
+        flash(
+            "Le paiement en ligne n'est pas disponible. "
+            "Contactez info@dictia.ca.",
+            'warning',
+        )
+        return redirect(url_for('marketing.tarifs'))
+    except ValueError as e:
+        logger.warning('Invalid checkout request: %s', e)
+        flash('Demande de paiement invalide.', 'danger')
+        return redirect(url_for('marketing.tarifs'))
+    except Exception as e:  # noqa: BLE001
+        logger.exception(
+            'Stripe Checkout creation failed for user %s plan %s: %s',
+            getattr(current_user, 'id', '?'), plan, e,
+        )
+        flash(
+            "Une erreur est survenue lors de l'ouverture du paiement. "
+            "Réessayez ou contactez info@dictia.ca.",
+            'danger',
+        )
+        return redirect(url_for('marketing.tarifs'))
+
+    # Stripe documents 303 See Other for hosted-Checkout redirects.
+    return redirect(session.url, code=303)
+
+
+@billing_bp.route('/success')
+def success():
+    """Post-payment confirmation page.
+
+    The session_id query param is preserved for optional client-side analytics
+    but is NOT trusted server-side — Stripe's webhook (B-2.8) is the source of
+    truth for subscription state. This page makes that asynchrony explicit
+    ("Votre abonnement sera activé sous quelques minutes.").
+    """
+    session_id = request.args.get('session_id')
+    return render_template(
+        'billing/success.html',
+        title='Paiement confirmé — DictIA',
+        session_id=session_id,
+    )
+
+
+@billing_bp.route('/cancel')
+def cancel():
+    """User cancelled the Stripe Checkout. No state to revert; no charge made."""
+    return render_template(
+        'billing/cancel.html',
+        title='Paiement annulé — DictIA',
+    )

src/billing/stripe_client.py

@@ -0,0 +1,139 @@
+"""Stripe SDK client wrapper (B-2.7).
+
+Lazy-initializes stripe.api_key from STRIPE_SECRET_KEY at first use, so the
+app can boot without Stripe credentials (CI, dev, contributor branches).
+Raises StripeNotConfiguredError if a Stripe API call is attempted without
+the key set.
+
+This module is intentionally thin: it owns the stripe.* call surface used by
+B-2.7 (Checkout) and is reused by B-2.8 (webhook signature verification).
+No subscription state is persisted here — the webhook is the source of truth
+for `user.subscription_status`. The only User mutation is `stripe_customer_id`
+(identity, not state).
+"""
+import os
+from typing import List
+
+import stripe
+
+
+class StripeNotConfiguredError(RuntimeError):
+    """Raised when STRIPE_SECRET_KEY (or a plan Price ID) is missing at call time."""
+
+
+def is_stripe_configured() -> bool:
+    """Return True if STRIPE_SECRET_KEY is set in the environment."""
+    return bool(os.environ.get('STRIPE_SECRET_KEY'))
+
+
+def _ensure_configured() -> None:
+    """Lazy-initialize stripe.api_key. Raises if STRIPE_SECRET_KEY is missing."""
+    if not is_stripe_configured():
+        raise StripeNotConfiguredError(
+            'STRIPE_SECRET_KEY is not set. Configure it before using billing.'
+        )
+    if not stripe.api_key:
+        stripe.api_key = os.environ['STRIPE_SECRET_KEY']
+
+
+def get_or_create_customer(user) -> str:
+    """Return the Stripe customer ID for `user`, creating one if needed.
+
+    Persists the Stripe customer ID on user.stripe_customer_id so subsequent
+    checkouts (and the webhook) can correlate Stripe events back to the user.
+    """
+    from src.database import db
+    _ensure_configured()
+    if user.stripe_customer_id:
+        return user.stripe_customer_id
+
+    customer = stripe.Customer.create(
+        email=user.email,
+        name=(user.name or user.username),
+        metadata={
+            'dictia_user_id': str(user.id),
+            'dictia_username': user.username,
+        },
+    )
+    user.stripe_customer_id = customer.id
+    db.session.commit()
+    return customer.id
+
+
+def create_checkout_session(
+    plan_slug: str,
+    period: str,
+    user,
+    success_url: str,
+    cancel_url: str,
+):
+    """Create a Stripe Checkout Session for the given plan + period.
+
+    Configuration applied:
+      - mode='subscription' (recurring)
+      - currency='cad'
+      - automatic_tax.enabled=true (Stripe applies TPS 5% + TVQ 9.975%)
+      - billing_address_collection='required' (needed for Tax)
+      - allow_promotion_codes=true
+      - Apple/Google Pay are auto-enabled for card payments in Stripe Dashboard
+      - Hardware plans (8/16) include a one-time setup line item AND the
+        recurring subscription line item.
+
+    The success_url is decorated with `?session_id={CHECKOUT_SESSION_ID}` so
+    the success page can optionally surface the session id (analytics).
+    """
+    from src.billing.plans import VALID_PERIODS, get_plan
+
+    _ensure_configured()
+    plan = get_plan(plan_slug)
+    if plan is None:
+        raise ValueError(f'Unknown plan: {plan_slug!r}')
+    if period not in VALID_PERIODS:
+        raise ValueError(
+            f'Invalid period: {period!r} (expected one of {VALID_PERIODS})'
+        )
+    if not plan.is_configured():
+        raise StripeNotConfiguredError(
+            f'Stripe Price IDs for {plan_slug!r} are not set in environment.'
+        )
+
+    customer_id = get_or_create_customer(user)
+
+    line_items: List[dict] = []
+    # One-time setup fee for hardware plans (DictIA 8 / DictIA 16)
+    if plan.has_setup_fee:
+        setup_id = plan.setup_price_id()
+        if setup_id:
+            line_items.append({'price': setup_id, 'quantity': 1})
+    # Recurring subscription
+    line_items.append({
+        'price': plan.price_id_for_period(period),
+        'quantity': 1,
+    })
+
+    # Inject CHECKOUT_SESSION_ID placeholder while preserving any existing query string
+    decorated_success_url = success_url + (
+        '&' if '?' in success_url else '?'
+    ) + 'session_id={CHECKOUT_SESSION_ID}'
+
+    metadata = {
+        'dictia_user_id': str(user.id),
+        'dictia_plan_slug': plan_slug,
+        'dictia_period': period,
+    }
+
+    return stripe.checkout.Session.create(
+        mode='subscription',
+        customer=customer_id,
+        line_items=line_items,
+        success_url=decorated_success_url,
+        cancel_url=cancel_url,
+        automatic_tax={'enabled': True},
+        currency='cad',
+        billing_address_collection='required',
+        customer_update={'address': 'auto', 'name': 'auto'},
+        allow_promotion_codes=True,
+        metadata=metadata,
+        # Webhook (B-2.8) reads metadata off the subscription, not the session
+        subscription_data={'metadata': metadata},
+    )

templates/billing/cancel.html

@@ -0,0 +1,47 @@
+{% extends 'marketing/base.html' %}
+
+{% block title %}{{ title or 'Paiement annulé — DictIA' }}{% endblock %}
+{% block description %}Paiement annulé. Aucun montant n'a été prélevé. Vous pouvez reprendre votre inscription à tout moment.{% endblock %}
+
+{% block content %}
+
+{# ===== HERO ===== #}
+<section class="bg-brand-navy text-white py-20" aria-labelledby="page-title">
+  <div class="max-w-[820px] mx-auto px-6 text-center">
+    <div class="w-20 h-20 bg-white/[0.06] border border-white/[0.12] rounded-full mx-auto mb-6 flex items-center justify-center text-3xl" aria-hidden="true">↺</div>
+    <p class="eyebrow grad-text mb-4">PAIEMENT ANNULÉ</p>
+    <h1 id="page-title" class="text-[clamp(2.25rem,4vw,3.5rem)] font-black mb-4">
+      Aucun problème — <span class="grad-text">aucun montant prélevé</span>.
+    </h1>
+    <p class="text-lg text-white/80">
+      Vous avez fermé la page de paiement avant de finaliser. Aucune carte n'a été débitée. Vous pouvez reprendre votre inscription à tout moment.
+    </p>
+  </div>
+</section>
+
+{# ===== INFO + NEXT STEPS ===== #}
+<section class="bg-brand-bg py-20" aria-labelledby="info-title">
+  <div class="max-w-[820px] mx-auto px-6">
+    <h2 id="info-title" class="sr-only">Que faire ensuite</h2>
+
+    <div class="bg-white p-8 rounded-[18px] border border-brand-border mb-8">
+      <h3 class="text-lg font-bold mb-3 text-brand-navy">Pourquoi avoir hésité&nbsp;?</h3>
+      <p class="text-sm text-brand-navy/80 leading-relaxed mb-4">
+        Si vous avez une question sur les forfaits, la conformité Loi&nbsp;25 ou la mise en service, notre équipe peut vous accompagner sans pression commerciale.
+      </p>
+      <p class="text-sm text-brand-navy/80 leading-relaxed">
+        Écrivez-nous à <a href="mailto:info@dictia.ca" class="grad-text font-semibold hover:underline">info@dictia.ca</a> ou appelez le <a href="tel:+15819968471" class="grad-text font-semibold hover:underline">(581)&nbsp;996-8471</a>. Réponse sous 2&nbsp;jours ouvrables.
+      </p>
+    </div>
+
+    <div class="text-center">
+      <div class="flex flex-col sm:flex-row gap-4 justify-center">
+        {% from 'macros/button.html' import button %}
+        {{ button('Revoir les tarifs', href='/tarifs', variant='primary', size='lg') }}
+        {{ button('Retour à l\'accueil', href='/', variant='ghost', size='lg') }}
+      </div>
+    </div>
+  </div>
+</section>
+
+{% endblock %}

templates/billing/success.html

@@ -0,0 +1,87 @@
+{% extends 'marketing/base.html' %}
+
+{% block title %}{{ title or 'Paiement confirmé — DictIA' }}{% endblock %}
+{% block description %}Paiement confirmé. Votre abonnement DictIA sera activé sous quelques minutes. Vous recevrez un courriel de confirmation.{% endblock %}
+
+{% block content %}
+
+{# ===== HERO ===== #}
+<section class="bg-brand-navy text-white py-20" aria-labelledby="page-title">
+  <div class="max-w-[820px] mx-auto px-6 text-center">
+    <div class="w-20 h-20 grad-bg rounded-full mx-auto mb-6 flex items-center justify-center text-4xl shadow-cta" aria-hidden="true">✓</div>
+    <p class="eyebrow grad-text mb-4">PAIEMENT CONFIRMÉ</p>
+    <h1 id="page-title" class="text-[clamp(2.25rem,4vw,3.5rem)] font-black mb-4">
+      Merci&nbsp;! Votre <span class="grad-text">paiement est confirmé</span>.
+    </h1>
+    <p class="text-lg text-white/80">
+      Votre abonnement sera activé sous quelques minutes. Vous recevrez un courriel de confirmation à l'adresse associée à votre compte.
+    </p>
+  </div>
+</section>
+
+{# ===== NEXT STEPS ===== #}
+<section class="bg-brand-bg py-20" aria-labelledby="next-steps-title">
+  <div class="max-w-[820px] mx-auto px-6">
+    <h2 id="next-steps-title" class="text-[clamp(1.75rem,2.5vw,2.25rem)] font-black mb-8 text-brand-navy text-center">
+      Prochaines étapes.
+    </h2>
+
+    <ol class="space-y-6">
+      <li class="bg-white p-6 rounded-[18px] border border-brand-border flex gap-4">
+        <span class="grad-bg text-white font-black w-10 h-10 rounded-full flex items-center justify-center flex-shrink-0 shadow-cta" aria-hidden="true">1</span>
+        <div>
+          <h3 class="font-bold text-brand-navy mb-1">Confirmation par courriel</h3>
+          <p class="text-sm text-brand-navy/80 leading-relaxed">
+            Vous recevrez un reçu détaillé (avec TPS et TVQ ventilées) dans les prochaines minutes. Vérifiez vos pourriels si rien n'arrive après 10&nbsp;minutes.
+          </p>
+        </div>
+      </li>
+
+      <li class="bg-white p-6 rounded-[18px] border border-brand-border flex gap-4">
+        <span class="grad-bg text-white font-black w-10 h-10 rounded-full flex items-center justify-center flex-shrink-0 shadow-cta" aria-hidden="true">2</span>
+        <div>
+          <h3 class="font-bold text-brand-navy mb-1">Activation de votre abonnement</h3>
+          <p class="text-sm text-brand-navy/80 leading-relaxed">
+            Votre statut d'abonnement sera mis à jour automatiquement dès que Stripe confirme la transaction (généralement sous 2&nbsp;minutes). Aucune action requise de votre part.
+          </p>
+        </div>
+      </li>
+
+      <li class="bg-white p-6 rounded-[18px] border border-brand-border flex gap-4">
+        <span class="grad-bg text-white font-black w-10 h-10 rounded-full flex items-center justify-center flex-shrink-0 shadow-cta" aria-hidden="true">3</span>
+        <div>
+          <h3 class="font-bold text-brand-navy mb-1">Mise en service</h3>
+          <p class="text-sm text-brand-navy/80 leading-relaxed">
+            Pour les forfaits <strong>DictIA&nbsp;Cloud</strong>&nbsp;: accès immédiat depuis votre tableau de bord.<br>
+            Pour les forfaits <strong>DictIA&nbsp;8</strong> et <strong>DictIA&nbsp;16</strong> (on-premise)&nbsp;: notre équipe vous contactera sous 1&nbsp;jour ouvrable pour planifier l'installation (~2&nbsp;semaines).
+          </p>
+        </div>
+      </li>
+    </ol>
+
+    {% if session_id %}
+    <p class="text-xs text-brand-navy/60 mt-8 text-center font-mono break-all">
+      Référence&nbsp;: {{ session_id }}
+    </p>
+    {% endif %}
+  </div>
+</section>
+
+{# ===== CTA ===== #}
+<section class="bg-white py-16" aria-labelledby="cta-title">
+  <div class="max-w-[820px] mx-auto px-6 text-center">
+    <h2 id="cta-title" class="text-[clamp(1.5rem,2vw,2rem)] font-black mb-4 text-brand-navy">
+      Une question&nbsp;?
+    </h2>
+    <p class="text-base text-brand-navy/80 mb-6">
+      Notre équipe est joignable à <a href="mailto:info@dictia.ca" class="grad-text font-semibold hover:underline">info@dictia.ca</a> ou au <a href="tel:+15819968471" class="grad-text font-semibold hover:underline">(581)&nbsp;996-8471</a>.
+    </p>
+    <div class="flex flex-col sm:flex-row gap-4 justify-center">
+      {% from 'macros/button.html' import button %}
+      {{ button('Retour à l\'accueil', href='/', variant='ghost', size='lg') }}
+      {{ button('Voir les tarifs', href='/tarifs', variant='secondary', size='lg') }}
+    </div>
+  </div>
+</section>
+
+{% endblock %}

tests/_run_stripe_checkout_windows.py

@@ -0,0 +1,74 @@
+"""Windows manual driver for tests/test_stripe_checkout.py.
+
+src/init_db.py imports `fcntl`, which is POSIX-only. On Windows we stub it
+before src.app gets imported, then run each test_* function and report.
+
+Run from the repo root:
+    py -3 tests/_run_stripe_checkout_windows.py
+"""
+import os
+import sys
+import types
+import traceback
+
+# 1) Stub fcntl BEFORE any import of src.* happens.
+if 'fcntl' not in sys.modules:
+    fcntl_stub = types.ModuleType('fcntl')
+    fcntl_stub.LOCK_EX = 2
+    fcntl_stub.LOCK_NB = 4
+    fcntl_stub.LOCK_UN = 8
+    fcntl_stub.LOCK_SH = 1
+    fcntl_stub.flock = lambda *_args, **_kw: None
+    fcntl_stub.fcntl = lambda *_args, **_kw: 0
+    sys.modules['fcntl'] = fcntl_stub
+
+# 2) Make repo root importable
+HERE = os.path.dirname(os.path.abspath(__file__))
+REPO = os.path.dirname(HERE)
+sys.path.insert(0, REPO)
+
+# 3) Test-friendly env defaults
+os.environ.setdefault('SQLALCHEMY_DATABASE_URI', 'sqlite:///:memory:')
+os.environ.setdefault('SECRET_KEY', 'test-secret-key-stripe')
+os.environ.setdefault('ENABLE_EMAIL_VERIFICATION', 'false')
+os.environ.setdefault('REQUIRE_EMAIL_VERIFICATION', 'false')
+os.environ.setdefault('TRANSCRIPTION_BASE_URL', 'http://test-stub')
+os.environ.setdefault('TRANSCRIPTION_API_KEY', 'test-stub')
+os.environ.setdefault('RATELIMIT_ENABLED', 'false')
+try:
+    sys.stdout.reconfigure(encoding='utf-8', errors='replace')
+    sys.stderr.reconfigure(encoding='utf-8', errors='replace')
+except Exception:
+    pass
+
+# 4) Import the test module and run every test_* function
+import importlib.util  # noqa: E402
+spec = importlib.util.spec_from_file_location(
+    'test_stripe_checkout',
+    os.path.join(HERE, 'test_stripe_checkout.py'),
+)
+mod = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(mod)
+
+tests = [(name, fn) for name, fn in vars(mod).items()
+         if name.startswith('test_') and callable(fn)]
+
+passed = 0
+failed = []
+for name, fn in tests:
+    try:
+        fn()
+        print(f'  PASS  {name}')
+        passed += 1
+    except Exception as e:  # noqa: BLE001
+        print(f'  FAIL  {name}: {type(e).__name__}: {e}')
+        failed.append((name, traceback.format_exc()))
+
+total = len(tests)
+print()
+print(f'Result: {passed}/{total} passed, {len(failed)} failed')
+if failed:
+    print('\n--- Failures ---\n')
+    for name, tb in failed:
+        print(f'### {name}\n{tb}\n')
+sys.exit(0 if not failed else 1)

tests/test_stripe_checkout.py

@@ -0,0 +1,593 @@
+"""Tests for B-2.7 — Stripe Checkout (3 plans CAD + TPS/TVQ + Apple/Google Pay).
+
+Covers:
+  - plans.py: Plan dataclass, env-resolved Price IDs, helpers, is_configured.
+  - stripe_client.py: lazy api_key init, get_or_create_customer, create_checkout_session.
+  - routes.py: GET /checkout/<plan>, /checkout/success, /checkout/cancel.
+  - Integration: app.py _PUBLIC_INDEXABLE_ENDPOINTS includes 'billing.success'.
+
+Mocks the stripe library functions (stripe.Customer.create, stripe.checkout.Session.create)
+via unittest.mock.patch — no real Stripe API calls.
+
+Note: pytest cannot collect this file on Windows native because src/init_db.py
+imports `fcntl` (POSIX-only). Use tests/_run_stripe_checkout_windows.py.
+"""
+import os
+import sys
+from unittest.mock import patch, MagicMock
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+os.environ.setdefault('SQLALCHEMY_DATABASE_URI', 'sqlite:///:memory:')
+os.environ.setdefault('SECRET_KEY', 'test-secret-key-stripe')
+os.environ.setdefault('ENABLE_EMAIL_VERIFICATION', 'false')
+os.environ.setdefault('REQUIRE_EMAIL_VERIFICATION', 'false')
+os.environ.setdefault('RATELIMIT_ENABLED', 'false')
+
+from src.app import app, db, bcrypt  # noqa: E402
+from src.models.user import User  # noqa: E402
+
+
+_PRICE_ENV_VARS = (
+    'STRIPE_SECRET_KEY',
+    'STRIPE_DICTIA_8_SETUP', 'STRIPE_DICTIA_8_MONTHLY', 'STRIPE_DICTIA_8_YEARLY',
+    'STRIPE_DICTIA_16_SETUP', 'STRIPE_DICTIA_16_MONTHLY', 'STRIPE_DICTIA_16_YEARLY',
+    'STRIPE_DICTIA_CLOUD_MONTHLY', 'STRIPE_DICTIA_CLOUD_YEARLY',
+)
+
+
+def _clear_stripe_env():
+    for k in _PRICE_ENV_VARS:
+        os.environ.pop(k, None)
+    # Reset stripe module-level api_key state
+    import stripe
+    stripe.api_key = None
+
+
+def _disable_csrf():
+    app.config['WTF_CSRF_ENABLED'] = False
+
+
+def _make_user(email='checkout@example.qc.ca', password='Password!123',
+               username=None, name='Checkout User',
+               stripe_customer_id=None):
+    hashed = bcrypt.generate_password_hash(password).decode('utf-8')
+    u = User(
+        username=username or email.split('@', 1)[0][:20],
+        email=email,
+        password=hashed,
+        email_verified=True,
+        name=name,
+        stripe_customer_id=stripe_customer_id,
+    )
+    db.session.add(u)
+    db.session.commit()
+    return u
+
+
+def _login_session(client, user):
+    with client.session_transaction() as sess:
+        sess['_user_id'] = str(user.id)
+        sess['_fresh'] = True
+
+
+# ----------------------------------------------------------------------
+# 1-2. is_stripe_configured
+# ----------------------------------------------------------------------
+
+def test_is_stripe_configured_when_env_set():
+    _clear_stripe_env()
+    try:
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        from src.billing.stripe_client import is_stripe_configured
+        assert is_stripe_configured() is True
+    finally:
+        _clear_stripe_env()
+
+
+def test_is_stripe_configured_when_env_unset():
+    _clear_stripe_env()
+    try:
+        from src.billing.stripe_client import is_stripe_configured
+        assert is_stripe_configured() is False
+    finally:
+        _clear_stripe_env()
+
+
+# ----------------------------------------------------------------------
+# 3-4. get_plan
+# ----------------------------------------------------------------------
+
+def test_get_plan_returns_known_plan():
+    from src.billing.plans import get_plan, Plan
+    plan = get_plan('dictia-cloud')
+    assert plan is not None
+    assert isinstance(plan, Plan)
+    assert plan.slug == 'dictia-cloud'
+    assert plan.has_setup_fee is False
+
+
+def test_get_plan_returns_none_for_unknown():
+    from src.billing.plans import get_plan
+    assert get_plan('foo') is None
+    assert get_plan('') is None
+
+
+# ----------------------------------------------------------------------
+# 5-7. Plan.is_configured
+# ----------------------------------------------------------------------
+
+def test_plan_is_configured_when_env_set():
+    _clear_stripe_env()
+    try:
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cloud_m'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cloud_y'
+        from src.billing.plans import get_plan
+        assert get_plan('dictia-cloud').is_configured() is True
+    finally:
+        _clear_stripe_env()
+
+
+def test_plan_is_not_configured_when_env_missing():
+    _clear_stripe_env()
+    try:
+        from src.billing.plans import get_plan
+        assert get_plan('dictia-cloud').is_configured() is False
+    finally:
+        _clear_stripe_env()
+
+
+def test_hardware_plan_requires_setup_env():
+    _clear_stripe_env()
+    try:
+        os.environ['STRIPE_DICTIA_8_MONTHLY'] = 'price_8_m'
+        os.environ['STRIPE_DICTIA_8_YEARLY'] = 'price_8_y'
+        # NO STRIPE_DICTIA_8_SETUP
+        from src.billing.plans import get_plan
+        assert get_plan('dictia-8').is_configured() is False
+        os.environ['STRIPE_DICTIA_8_SETUP'] = 'price_8_setup'
+        assert get_plan('dictia-8').is_configured() is True
+    finally:
+        _clear_stripe_env()
+
+
+# ----------------------------------------------------------------------
+# 8-9. get_or_create_customer
+# ----------------------------------------------------------------------
+
+def test_get_or_create_customer_creates_when_missing():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        db.create_all()
+        try:
+            user = _make_user(email='newcust@example.qc.ca', name='Alice')
+            assert user.stripe_customer_id is None
+            with patch('src.billing.stripe_client.stripe.Customer.create') as mock_cust:
+                mock_cust.return_value = MagicMock(id='cus_fakeNEW')
+                from src.billing.stripe_client import get_or_create_customer
+                cust_id = get_or_create_customer(user)
+            assert cust_id == 'cus_fakeNEW'
+            mock_cust.assert_called_once()
+            kwargs = mock_cust.call_args.kwargs
+            assert kwargs['email'] == 'newcust@example.qc.ca'
+            assert kwargs['name'] == 'Alice'
+            assert kwargs['metadata']['dictia_user_id'] == str(user.id)
+            db.session.refresh(user)
+            assert user.stripe_customer_id == 'cus_fakeNEW'
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_get_or_create_customer_reuses_existing():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        db.create_all()
+        try:
+            user = _make_user(email='oldcust@example.qc.ca',
+                              stripe_customer_id='cus_existing')
+            with patch('src.billing.stripe_client.stripe.Customer.create') as mock_cust:
+                from src.billing.stripe_client import get_or_create_customer
+                cust_id = get_or_create_customer(user)
+            assert cust_id == 'cus_existing'
+            mock_cust.assert_not_called()
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+# ----------------------------------------------------------------------
+# 10-13. create_checkout_session
+# ----------------------------------------------------------------------
+
+def test_create_checkout_session_includes_setup_for_hardware_plan():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_8_SETUP'] = 'price_setup'
+        os.environ['STRIPE_DICTIA_8_MONTHLY'] = 'price_8m'
+        os.environ['STRIPE_DICTIA_8_YEARLY'] = 'price_8y'
+        db.create_all()
+        try:
+            user = _make_user(email='hwsetup@example.qc.ca', name='Bob')
+            with patch('src.billing.stripe_client.stripe.Customer.create') as mock_cust, \
+                 patch('src.billing.stripe_client.stripe.checkout.Session.create') as mock_sess:
+                mock_cust.return_value = MagicMock(id='cus_x')
+                mock_sess.return_value = MagicMock(url='https://checkout.stripe.test/cs_x')
+                from src.billing.stripe_client import create_checkout_session
+                create_checkout_session(
+                    plan_slug='dictia-8', period='monthly', user=user,
+                    success_url='https://x.ca/success', cancel_url='https://x.ca/cancel',
+                )
+                kwargs = mock_sess.call_args.kwargs
+                assert len(kwargs['line_items']) == 2
+                assert kwargs['line_items'][0]['price'] == 'price_setup'
+                assert kwargs['line_items'][1]['price'] == 'price_8m'
+                assert kwargs['mode'] == 'subscription'
+                assert kwargs['currency'] == 'cad'
+                assert kwargs['automatic_tax']['enabled'] is True
+                assert kwargs['allow_promotion_codes'] is True
+                assert kwargs['billing_address_collection'] == 'required'
+                # success_url must include CHECKOUT_SESSION_ID placeholder
+                assert '{CHECKOUT_SESSION_ID}' in kwargs['success_url']
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_create_checkout_session_no_setup_for_cloud_plan():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cm'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cy'
+        db.create_all()
+        try:
+            user = _make_user(email='cloudplan@example.qc.ca', name='Carol')
+            with patch('src.billing.stripe_client.stripe.Customer.create') as mock_cust, \
+                 patch('src.billing.stripe_client.stripe.checkout.Session.create') as mock_sess:
+                mock_cust.return_value = MagicMock(id='cus_y')
+                mock_sess.return_value = MagicMock(url='https://x/cs_y')
+                from src.billing.stripe_client import create_checkout_session
+                create_checkout_session(
+                    plan_slug='dictia-cloud', period='monthly', user=user,
+                    success_url='https://x.ca/success', cancel_url='https://x.ca/cancel',
+                )
+                kwargs = mock_sess.call_args.kwargs
+                assert len(kwargs['line_items']) == 1
+                assert kwargs['line_items'][0]['price'] == 'price_cm'
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_create_checkout_session_uses_yearly_price_when_period_yearly():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cm'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cy'
+        db.create_all()
+        try:
+            user = _make_user(email='yearly@example.qc.ca', name='Dan')
+            with patch('src.billing.stripe_client.stripe.Customer.create') as mock_cust, \
+                 patch('src.billing.stripe_client.stripe.checkout.Session.create') as mock_sess:
+                mock_cust.return_value = MagicMock(id='cus_z')
+                mock_sess.return_value = MagicMock(url='https://x/cs_z')
+                from src.billing.stripe_client import create_checkout_session
+                create_checkout_session(
+                    plan_slug='dictia-cloud', period='yearly', user=user,
+                    success_url='https://x.ca/success', cancel_url='https://x.ca/cancel',
+                )
+                kwargs = mock_sess.call_args.kwargs
+                assert kwargs['line_items'][0]['price'] == 'price_cy'
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_create_checkout_session_includes_metadata():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cm'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cy'
+        db.create_all()
+        try:
+            user = _make_user(email='meta@example.qc.ca', name='Eve')
+            with patch('src.billing.stripe_client.stripe.Customer.create') as mock_cust, \
+                 patch('src.billing.stripe_client.stripe.checkout.Session.create') as mock_sess:
+                mock_cust.return_value = MagicMock(id='cus_q')
+                mock_sess.return_value = MagicMock(url='https://x/cs_q')
+                from src.billing.stripe_client import create_checkout_session
+                create_checkout_session(
+                    plan_slug='dictia-cloud', period='monthly', user=user,
+                    success_url='https://x.ca/success', cancel_url='https://x.ca/cancel',
+                )
+                kwargs = mock_sess.call_args.kwargs
+                meta = kwargs['metadata']
+                assert meta['dictia_user_id'] == str(user.id)
+                assert meta['dictia_plan_slug'] == 'dictia-cloud'
+                assert meta['dictia_period'] == 'monthly'
+                # Subscription-level metadata too (used by webhook B-2.8)
+                sub_meta = kwargs['subscription_data']['metadata']
+                assert sub_meta['dictia_user_id'] == str(user.id)
+                assert sub_meta['dictia_plan_slug'] == 'dictia-cloud'
+                assert sub_meta['dictia_period'] == 'monthly'
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+# ----------------------------------------------------------------------
+# 14-17. create_checkout_session error paths
+# ----------------------------------------------------------------------
+
+def test_create_checkout_session_raises_on_unknown_plan():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        db.create_all()
+        try:
+            user = _make_user(email='unkplan@example.qc.ca')
+            from src.billing.stripe_client import create_checkout_session
+            try:
+                create_checkout_session(
+                    plan_slug='foo', period='monthly', user=user,
+                    success_url='https://x/s', cancel_url='https://x/c',
+                )
+                raise AssertionError('Expected ValueError')
+            except ValueError:
+                pass
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_create_checkout_session_raises_on_invalid_period():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cm'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cy'
+        db.create_all()
+        try:
+            user = _make_user(email='badperiod@example.qc.ca')
+            from src.billing.stripe_client import create_checkout_session
+            try:
+                create_checkout_session(
+                    plan_slug='dictia-cloud', period='quarterly', user=user,
+                    success_url='https://x/s', cancel_url='https://x/c',
+                )
+                raise AssertionError('Expected ValueError')
+            except ValueError:
+                pass
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_create_checkout_session_raises_when_stripe_not_configured():
+    with app.app_context():
+        _clear_stripe_env()
+        # NO STRIPE_SECRET_KEY
+        db.create_all()
+        try:
+            user = _make_user(email='nokey@example.qc.ca')
+            from src.billing.stripe_client import (
+                create_checkout_session, StripeNotConfiguredError,
+            )
+            try:
+                create_checkout_session(
+                    plan_slug='dictia-cloud', period='monthly', user=user,
+                    success_url='https://x/s', cancel_url='https://x/c',
+                )
+                raise AssertionError('Expected StripeNotConfiguredError')
+            except StripeNotConfiguredError:
+                pass
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_create_checkout_session_raises_when_plan_env_missing():
+    with app.app_context():
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        # NO price IDs for dictia-cloud
+        db.create_all()
+        try:
+            user = _make_user(email='noprice@example.qc.ca')
+            from src.billing.stripe_client import (
+                create_checkout_session, StripeNotConfiguredError,
+            )
+            try:
+                create_checkout_session(
+                    plan_slug='dictia-cloud', period='monthly', user=user,
+                    success_url='https://x/s', cancel_url='https://x/c',
+                )
+                raise AssertionError('Expected StripeNotConfiguredError')
+            except StripeNotConfiguredError:
+                pass
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+# ----------------------------------------------------------------------
+# 18-22. /checkout/<plan> route
+# ----------------------------------------------------------------------
+
+def test_checkout_route_redirects_to_stripe_url():
+    with app.app_context():
+        _disable_csrf()
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cm'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cy'
+        db.create_all()
+        try:
+            user = _make_user(email='rt-redir@example.qc.ca', name='Frank')
+            with app.test_client() as client:
+                _login_session(client, user)
+                with patch('src.billing.routes.create_checkout_session') as mock_create:
+                    mock_create.return_value = MagicMock(
+                        url='https://checkout.stripe.test/cs_redir'
+                    )
+                    resp = client.get('/checkout/dictia-cloud?period=monthly',
+                                      follow_redirects=False)
+                assert resp.status_code == 303
+                assert resp.headers['Location'] == 'https://checkout.stripe.test/cs_redir'
+                # Ensure routes called the helper with the right args
+                mock_create.assert_called_once()
+                call_kwargs = mock_create.call_args.kwargs
+                assert call_kwargs['plan_slug'] == 'dictia-cloud'
+                assert call_kwargs['period'] == 'monthly'
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_checkout_route_unknown_plan_redirects_to_tarifs():
+    with app.app_context():
+        _disable_csrf()
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        db.create_all()
+        try:
+            user = _make_user(email='rt-unk@example.qc.ca')
+            with app.test_client() as client:
+                _login_session(client, user)
+                resp = client.get('/checkout/foo', follow_redirects=False)
+                assert resp.status_code == 302
+                assert '/tarifs' in resp.headers['Location']
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_checkout_route_normalizes_invalid_period_to_monthly():
+    with app.app_context():
+        _disable_csrf()
+        _clear_stripe_env()
+        os.environ['STRIPE_SECRET_KEY'] = 'sk_test_fake'
+        os.environ['STRIPE_DICTIA_CLOUD_MONTHLY'] = 'price_cm'
+        os.environ['STRIPE_DICTIA_CLOUD_YEARLY'] = 'price_cy'
+        db.create_all()
+        try:
+            user = _make_user(email='rt-period@example.qc.ca')
+            with app.test_client() as client:
+                _login_session(client, user)
+                with patch('src.billing.routes.create_checkout_session') as mock_create:
+                    mock_create.return_value = MagicMock(
+                        url='https://checkout.stripe.test/cs_norm'
+                    )
+                    resp = client.get('/checkout/dictia-cloud?period=quarterly',
+                                      follow_redirects=False)
+                assert resp.status_code == 303
+                assert mock_create.call_args.kwargs['period'] == 'monthly'
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_checkout_route_requires_login():
+    with app.app_context():
+        _disable_csrf()
+        _clear_stripe_env()
+        db.create_all()
+        try:
+            with app.test_client() as client:
+                resp = client.get('/checkout/dictia-cloud',
+                                  follow_redirects=False)
+                assert resp.status_code == 302
+                assert '/login' in resp.headers['Location']
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+def test_checkout_route_friendly_message_when_stripe_not_configured():
+    with app.app_context():
+        _disable_csrf()
+        _clear_stripe_env()
+        # NO STRIPE_SECRET_KEY
+        db.create_all()
+        try:
+            user = _make_user(email='rt-noconfig@example.qc.ca')
+            with app.test_client() as client:
+                _login_session(client, user)
+                resp = client.get('/checkout/dictia-cloud',
+                                  follow_redirects=False)
+                assert resp.status_code == 302
+                assert '/tarifs' in resp.headers['Location']
+                # Follow the redirect to see the flashed message
+                resp2 = client.get('/tarifs')
+                body = resp2.get_data(as_text=True)
+                assert 'info@dictia.ca' in body
+        finally:
+            db.session.rollback()
+            db.drop_all()
+            _clear_stripe_env()
+
+
+# ----------------------------------------------------------------------
+# 23-24. /checkout/success and /checkout/cancel
+# ----------------------------------------------------------------------
+
+def test_success_route_renders_template():
+    with app.app_context():
+        _disable_csrf()
+        db.create_all()
+        try:
+            with app.test_client() as client:
+                resp = client.get('/checkout/success?session_id=cs_test_abc')
+                assert resp.status_code == 200
+                body = resp.get_data(as_text=True)
+                # Body should mention the async-activation note (per spec)
+                assert 'minutes' in body.lower() or 'activé' in body.lower() \
+                    or 'activée' in body.lower() or 'confirmé' in body.lower()
+        finally:
+            db.session.rollback()
+            db.drop_all()
+
+
+def test_cancel_route_renders_template():
+    with app.app_context():
+        _disable_csrf()
+        db.create_all()
+        try:
+            with app.test_client() as client:
+                resp = client.get('/checkout/cancel')
+                assert resp.status_code == 200
+                body = resp.get_data(as_text=True)
+                # "no charge made" reassurance in French
+                assert 'aucun' in body.lower() or 'annulé' in body.lower()
+        finally:
+            db.session.rollback()
+            db.drop_all()
+
+
+# ----------------------------------------------------------------------
+# 25. Integration with no-crawl headers
+# ----------------------------------------------------------------------
+
+def test_success_route_in_public_indexable_endpoints():
+    """Defensive: 'billing.success' was added to _PUBLIC_INDEXABLE_ENDPOINTS in B-1.3."""
+    from src.app import _PUBLIC_INDEXABLE_ENDPOINTS
+    assert 'billing.success' in _PUBLIC_INDEXABLE_ENDPOINTS