Idempotent Payment API

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An idempotent payment API for teams that need safe retries across payment intents, captures, invoice actions, and webhook-driven recovery flows.

Why teams choose this primitive

Flint documents idempotency-backed write paths clearly instead of treating retry safety as tribal knowledge.

Payment-intent create, update, confirm, capture, and cancel flows all support idempotency keys on the public API.

The order-first model makes retries easier to reason about because payment state stays attached to a durable business record.

Build This When

Your integration needs safe retries after network failures, worker restarts, or webhook-triggered replays.

The same business action might create, confirm, capture, refund, or send an invoice, and duplicate execution would be expensive.

You want retry safety defined by the API surface itself instead of relying on ad hoc application-side dedupe.

Quickstart

Start with the first request.

API Reference

Open the REST surface.

Orders First

See the core model.

Benchmark

Compare developer workflows.

Why Developers Reach for This

Teams searching idempotent payment APIs usually want to stop duplicate charges, duplicate refunds, and ambiguous retry behavior after network failures or webhook retries.

Case 1

Retry-safe payment creation

Reuse one business-action key when create or confirm requests fail ambiguously so a retry does not duplicate the payment flow.

Case 2

Capture after fulfillment

Protect delayed capture operations from duplicate execution when fulfillment jobs or operators retry the same authorization.

Case 3

Invoice and reminder actions

Keep invoice-state changes repeatable when sending, voiding, or recording manual payment after flaky network edges.

Case 4

Webhook-driven recovery

Use idempotent write paths so downstream jobs can retry safely after event redelivery or transient failures.

Choose Something Else When

Use basic error handling alone when duplicate execution is low-risk and the write path is not business critical.

Use webhook operations pages when the main problem is delivery inspection and endpoint debugging, not write-path replay safety.

Use the broader payment API page when idempotency is only one concern inside a larger architecture decision.

Implementation References

Idempotency Guide

Source of truth for public write paths that support idempotency keys and how retries behave.

Payments API

See create, confirm, capture, and cancel routes that accept Idempotency-Key.

Invoices API

Review which invoice actions are idempotency-backed and which session flows are not.

Explore retries, debugging, and adjacent payment controls

These pages help connect retry safety to the broader operational model around Flint integrations.

Webhook Infrastructure for Developers

Use this when retries also need delivery history, signature verification, and event inspection.

API Request Logs for Payment Integrators

Useful when retry safety is only part of the debugging story and you need request-level visibility too.

Payment API

Go broader when the real question is Flint's order-first payment model rather than retry semantics alone.

Next Step

Move from evaluation into a real integration

Start with the quickstart, wire the right Flint primitive, then issue keys when the flow is ready for real traffic.