I will integrate checkout, subscriptions and webhooks

I integrate payment flows into web products with a focus on clear state transitions and reliable webhooks. The work can include checkout setup, subscription state, success and cancellation routes, signature verification, idempotency, order or entitlement updates and failure handling. I document the provider boundary and the test cases needed before production. The buyer owns the payment account, legal terms, tax configuration and provider approval. Please share the provider, product model, existing backend and required post-payment behavior.