March 2, 2026 6 min read
PDF API Retries and Idempotency: Avoid Duplicate Processing
How to safely retry generation/conversion jobs without duplicated outputs.
Transient failures are normal. Duplicate invoices are not. Pair idempotency keys with durable state transitions.
Recommended model
- Create `job_id` and store `PENDING` state before API call.
- Send idempotency token (or deterministic hash) per operation.
- Retry only on retriable codes (429/5xx/network timeout).
- Mark `DONE` only after output URL/hash is persisted.
Backoff policy
Use exponential backoff with jitter: 1s, 2s, 4s, 8s + random jitter cap.
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