> For the complete documentation index, see [llms.txt](/llms.txt)

# Idempotency keys

Glotto treats the **`Idempotency-Key`** header as a first-class concept, so retrying a
mutation can't accidentally create two of something. When an operation's spec advertises
the header, the generated SDK **auto-injects a fresh UUID** on each `POST`, and the server
dedupes on it.

## How it interacts with retries

Glotto ships built-in retries — but deliberately *not* blind ones:

- **Safe methods** (`GET` / `HEAD`) plus `5xx` and retryable transport errors are retried
  with exponential backoff + jitter, out of the box.
- **Mutations** are retried only when their OpenAPI spec advertises `Idempotency-Key`
  (so the server can dedupe a replayed request). Mutations without the advertised header
  are not retried by default — configurable via `client_settings`.

This pairs Stainless-style "retries out of the box" with the safer "don't retry blindly"
discipline: the SDK auto-injects the key, callers (and the SDK) can retry, and the server
dedupes.