# Fastify v5.12.0

- Product: Fastify (https://whatsnew.fyi/product/fastify)
- Vendor: Fastify
- Date: 2026-08-13
- Version: v5.12.0
- Original notes: https://github.com/fastify/fastify/releases/tag/v5.12.0
- Permalink: https://whatsnew.fyi/product/fastify/releases/v5.12.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **fixed** — Remove raw response headers
- **added** — Add Reply.prototype.mediaType
- **fixed** — Return undefined for invalid media types in content-type handling

##### What's Changed
* chore(sponsor): add testmu ai by @Eomm in https://github.com/fastify/fastify/pull/6922
* docs: add per-route logging for Google Cloud Functions by @slegarraga in https://github.com/fastify/fastify/pull/6907
* test: remove @sinonjs/fake-timers by @climba03003 in https://github.com/fastify/fastify/pull/6934
* [Backport 5.x] fix: remove raw response headers by @github-actions[bot] in https://github.com/fastify/fastify/pull/6939
* [Backport 5.x] test: use process-warning spyWarning for testing by @github-actions[bot] in https://github.com/fastify/fastify/pull/6945
* [Backport 5.x] feat: add `Reply.prototype.mediaType` by @github-actions[bot] in https://github.com/fastify/fastify/pull/6946
* [Backport 5.x] fix(content-type): return `undefined` for invalid media types by @github-actions[bot] in https://github.com/fastify/fastify/pull/6947


**Full Changelog**: https://github.com/fastify/fastify/compare/v5.11.3...v5.12.0