Cashier Mollie Laravel Package

Technical Evaluation

Architecture Fit

• Pros:

  • Seamlessly integrates with Laravel Cashier, leveraging its existing billing infrastructure (e.g., subscriptions, invoices, webhooks).
  • Mollie’s API alignment with Cashier’s patterns reduces custom integration overhead.
  • Supports recurring payments, one-time charges, and subscription management—core features for SaaS/membership models.
  • MIT license enables easy adoption without legal barriers.

• Cons:

  • Archived Status: The original laravel/cashier-mollie is deprecated; migration to mollie/laravel-cashier-mollie (v2) is mandatory. This introduces technical debt if not addressed immediately.
  • Lack of Actively Maintained Dependents: No dependents suggest niche adoption; may lack community-driven fixes or updates.
  • PHP/Laravel Version Lock: Last release (2021) may not support newer Laravel (10.x) or PHP (8.2+) features without backporting or forks.

Integration Feasibility

• High for Greenfield Projects: Ideal if starting fresh with Laravel 8/9 and Mollie as the sole payment provider.
• Moderate for Existing Systems:
  • Requires alignment with Cashier’s subscription model (e.g., User model must extend Billable).
  • Webhook handling (e.g., mollie.webhook-cashier) must be configured for real-time updates (e.g., failed payments, cancellations).
  • Custom logic may be needed for Mollie-specific features (e.g., split payments, mandates for SEPA Direct Debit).
• API Dependencies:
  • Mollie’s API changes post-2021 may break compatibility without updates.
  • Rate limits, retry logic, and idempotency must be handled (Cashier provides abstractions but may need tuning).

Technical Risk

• Critical:
  • Deprecation Risk: Migration to mollie/laravel-cashier-mollie (v2) is non-trivial; breaking changes may exist (e.g., webhook payloads, method signatures).
  • Security: No recent releases → potential unpatched vulnerabilities in underlying dependencies (e.g., Guzzle HTTP client).
  • Testing: Lack of active maintenance means limited QA for edge cases (e.g., refunds, prorations).
• Mitigable:
  • Fallback Mechanisms: Implement circuit breakers for Mollie API failures (e.g., queue failed payments for manual review).
  • Feature Gaps: Use Mollie’s native PHP SDK for unsupported features (e.g., payouts, multi-currency).
  • Monitoring: Log all Mollie API calls/responses to detect drift from documented behavior.

Key Questions

1. Migration Path:
   • What’s the effort to upgrade from laravel/cashier-mollie (v1) to mollie/laravel-cashier-mollie (v2)? Are there migration tools or docs?
   • How will webhook signatures/validation change between versions?
2. Compatibility:
   • Does the package support Laravel 10.x/PHP 8.2+? If not, what’s the backporting effort?
   • Are there conflicts with other Cashier drivers (e.g., Stripe) in the same project?
3. Feature Parity:
   • Does v2 support all v1 features (e.g., subscription trials, dunning management)?
   • How are Mollie-specific features (e.g., "Issuer ID" for SEPA) exposed?
4. Support:
   • Who maintains the package now? Mollie’s official repo or community?
   • Are there SLAs for critical issues (e.g., payment failures during peak loads)?
5. Cost/Compliance:
   • Does Mollie’s pricing model (e.g., per-transaction fees) align with business needs?
   • Are there regional compliance requirements (e.g., PSD2 SCA for EU)?

Integration Approach

Stack Fit

• Ideal For:
  • Laravel-based SaaS platforms with subscription models (e.g., B2B, B2C, or hybrid).
  • Projects already using Laravel Cashier (minimal additional setup).
  • Teams comfortable with PHP and Mollie’s API (low-code customization needed).
• Less Suitable For:
  • Polyglot stacks (e.g., Node.js backend) or non-Laravel PHP frameworks.
  • Projects requiring multi-provider support (e.g., Stripe + PayPal) without abstraction layers.

Migration Path

1. Assessment Phase:
   • Audit current billing flow (e.g., Stripe/Cashier usage) to identify gaps/dependencies.
   • Verify Mollie API access (test mode/live keys, webhook endpoints).
2. Dependency Upgrade:
   • Replace laravel/cashier-mollie with mollie/laravel-cashier-mollie (v2).
   • Update composer.json and run composer update.
3. Configuration:
   • Publish and configure Cashier’s Mollie config (config/cashier.php).
   • Set up Mollie webhook endpoint (e.g., /mollie/webhook-cashier) with HTTPS.
4. Data Migration (if applicable):
   • Migrate existing subscriptions/invoices from old provider to Mollie (use Cashier’s Subscription::create() or Mollie’s API).
   • Handle legacy payment data (e.g., store Mollie id alongside old provider’s id temporarily).
5. Testing:
   • Unit Tests: Mock Mollie API responses to test Cashier’s subscription logic.
   • Integration Tests: Use Mollie’s test mode to simulate payments, refunds, and cancellations.
   • Webhook Validation: Test all Mollie event types (e.g., payment.authorized, subscription.cancelled).
6. Rollout:
   • Feature flag Mollie for a subset of users (canary release).
   • Monitor for failures (e.g., Mollie\Api\Exceptions\ApiException).

Compatibility

• Laravel Versions:
  • Target Laravel 8/9 for v2; Laravel 10 may require manual patches or waiting for updates.
• PHP Extensions:
  • Requires php-curl and php-openssl for API calls.
• Database:
  • No schema changes needed if using Cashier’s default tables (subscriptions, invoices).
  • Custom tables may be needed for Mollie-specific fields (e.g., mandate_id for SEPA).
• Third-Party Services:
  • Conflicts unlikely unless using another Cashier driver (e.g., Stripe). Use separate Billable models if needed.

Sequencing

1. Phase 1: Replace package + configure basic subscriptions.
2. Phase 2: Implement webhooks and retry logic for failed payments.
3. Phase 3: Add Mollie-specific features (e.g., mandates, split payments).
4. Phase 4: Deprecate old payment provider (if applicable) and clean up legacy data.

Operational Impact

Maintenance

• Proactive Tasks:
  • Monitoring: Track Mollie API uptime (e.g., via Laravel Horizon or external tools like Pingdom).
  • Logging: Log all Mollie API interactions (request/response) for debugging.
  • Backups: Ensure subscription data is backed up before migrations.
• Reactive Tasks:
  • Webhook Failures: Implement dead-letter queues for unprocessed webhook events.
  • Rate Limits: Handle 429 Too Many Requests via exponential backoff (Cashier may need customization).
  • Schema Updates: Mollie’s API changes may require Cashier updates (follow mollie/laravel-cashier-mollie releases).

Support

• Internal:
  • Train devs on Mollie’s API (e.g., testing payments, refunds, and disputes).
  • Document common issues (e.g., "Payment failed due to insufficient funds").
• External:
  • Provide user-facing docs for Mollie-specific flows (e.g., "How to update payment methods").
  • Set up Mollie’s customer support channels for merchant disputes.
• Escalation Path:
  • Direct issues to Mollie’s support if related to API limits or fraud (use security@mollie.com for security issues).

Scaling

• Performance:
  • API Calls: Batch webhook processing to avoid rate limits (e.g., use Laravel queues).
  • Database: Index subscriptions.user_id and invoices.subscription_id for large user bases.
  • Caching: Cache subscription plans (if static) to reduce API calls.
• Load Testing:
  • Simulate high concurrency for subscription creation/cancellation.
  • Test webhook processing under load (e.g., 1000 events/minute).
• Horizontal Scaling:
  • Stateless design (Cashier is stateless; Mollie API is external).
  • Use Laravel Forge/Vapor for auto-scaling if needed.

Failure Modes

| Failure Scenario | Impact | Mitigation | |-------------------------------------|-------------------------------------