Payment API Integration Checklist for Going Live
By PayEurasia Team · 2 October 2026 · 6 min read
Last updated 2 October 2026
Everything to confirm before a payment integration goes live: authentication, idempotency, webhooks, errors, reconciliation, monitoring and security.
Most payment integrations work in the sandbox. The ones that also work in production are the ones whose teams checked the unglamorous details before launch. This checklist collects those details — the items that, when missed, cause lost payments, duplicate payouts and weekend incidents.
What this guide covers
- Authentication and secrets
- Request safety
- Webhooks
- Error handling and user messaging
- Reconciliation from day one
- Monitoring and launch plan
Authentication and secrets
Store API keys in a secrets manager, never in source code or client-side bundles. Use separate keys for sandbox and production, restrict production keys to server environments and, where supported, allowlist your server IPs.
Plan key rotation now: know how to issue a new key, deploy it and revoke the old one without downtime.
Request safety
Send an idempotency key on every create request and reuse it on retries. Set sensible timeouts and retry only on network errors and 5xx responses, with exponential backoff and jitter.
Never retry on 4xx validation errors. Fix the request instead.
Webhooks
Verify signatures on the raw body, acknowledge quickly, process asynchronously, deduplicate on event ID and alert on delivery failures. Test every event type in the sandbox, including failures, returns and refunds.
Details are in the payment webhooks guide.
Error handling and user messaging
Map provider error codes to clear customer messages and to internal categories: retryable, payer action needed, or permanent failure. Show customers what to do next rather than a generic error.
Log the provider's request ID with every error so support can trace issues in one step.
Reconciliation from day one
Store the provider transaction reference on every record. Run a daily job that compares your records against provider settlement reports and flags mismatches, as described in the payment reconciliation guide.
A reconciliation break found on day two is a bug fix; one found on day ninety is an audit.
Monitoring and launch plan
Track success rate, latency and webhook lag per method, with alerts on sudden drops. Launch gradually: a small share of traffic first, then ramp while watching metrics. Keep a rollback plan and an on-call contact at the provider.
PayEurasia's API documentation and status page support each of these steps.
Frequently asked questions
What is the most common go-live mistake?
Missing idempotency on retries, which leads to duplicate payments or payouts.
Should I test failures in the sandbox?
Yes. Test declines, timeouts, returns and refunds, not just successful payments.
How do I launch safely?
Ramp traffic gradually while monitoring success rates and webhook delivery.
Where should API keys live?
In a server-side secrets manager, never in client code or repositories.
When should reconciliation start?
On the first day of live traffic.
Where PayEurasia fits
PayEurasia runs local collections and payouts across Bangladesh, India, Pakistan and Nepal behind a single API, one reconciliation model and one settlement relationship. Provider redundancy sits behind that API, so an acquirer outage degrades approval rates instead of stopping money movement.
If you are scoping an integration, the API overview explains the object model and the API documentation covers authentication, webhooks and error handling. Merchant onboarding lists the documents needed before a live account is issued, and Compliance sets out the KYC and AML framework applied to every merchant.
Related guides
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