> ## Documentation Index > Fetch the complete documentation index at: https://docs.baselayer.com/llms.txt > Use this file to discover all available pages before exploring further. # Idempotency Keys on Every Search and Request > Sep 29, 2026 You can now safely retry any request that starts a search or analysis, without the risk of creating, and paying for, a duplicate.
Send an optional `Idempotency-Key` header (up to 255 printable characters) on `POST` requests for business, person, international, lien, docket and DMF searches, website analysis, web presence, adverse media, employee verification, NAICS prediction and TIN verification. If you retry with the same key and the same body, Baselayer returns the original resource instead of creating a new one, with the header `Idempotent-Replayed: true`. You get `202` while the request is still in progress, or the route's normal success code once it has finished. Reusing a key with a different body returns `422` (code `6700`). Two simultaneous requests with the same key return a retryable `409` (code `6701`). Keys are scoped to your application and resource type. Resources and their webhook payloads now include the `idempotency_key` you sent. Batch and export requests are not yet covered. No integration changes required. The header is optional. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.