Every header the transmute API sets — request correlation, rate limit, quota, warnings, paging, and idempotency indicators.
Correlation
Header On Meaning X-Request-IdEvery response Correlation id (req_<ulid>), echoed from your inbound X-Request-Id if you send one. Also present as requestId in error bodies. Quote this to support — it's how we find a request in our body-free logs.
Rate limit (per-second token bucket)
Set on every authenticated response — see Rate Limits & Quotas :
Header Meaning RateLimit-LimitRequests allowed in the current window RateLimit-RemainingRequests remaining RateLimit-ResetSeconds until the window resets Retry-AfterOn 429 only — seconds to wait
Monthly quota
Set on the four metered routes (POST /v1/convert, /v1/normalize, /v1/validate, /v1/enrich):
Header Meaning X-Quota-LimitThe pool this key draws from: your plan's monthly included conversions (live keys) or the one-time 250-request test allowance (test keys) X-Quota-RemainingRemaining in that pool before this request, clamped at 0
Header On Meaning X-Transmute-WarningsBare-document responses Count of warnings that couldn't ride in the body X-Transmute-Warnings-LinkBare-document responses Link to the warning registry X-Transmute-PagesPaged text/plain MT output Number of MT pages concatenated in the response
Idempotency
Header Meaning Idempotency-Replayed: trueThis response came from the 24-hour replay cache — it was not re-executed and not billed. See Idempotency .
Header Meaning Authorization: Bearer ...Your API key or OAuth token Idempotency-KeyOpt-in safe retries (1–255 chars) X-Request-IdYour own correlation id, echoed back X-Transmute-From / X-Transmute-To / X-Transmute-To-VersionFormat selection for raw bodies (lowest precedence — envelope and query parameters win) Acceptapplication/json (envelope, default), application/xml / text/plain (bare document)
