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FastMCP 3.0 is here! This is our largest and most ambitious release ever. We've re-architected the framework to support the next generation of MCP applications. It's time to move fast and make things. 🧵

20/1/26, 7:08 pm11 reposts36 likes

Jeremiah Lowin

@jlowin.dev

20 Jan

We're moving past "tool servers." Source from anywhere. Compose and transform freely. Personalize per-user. Track state across sessions. Control access. Run long operations. Version your APIs. Observe everything. We call this the context era: www.jlowin.dev/blog/fastmcp-3

jlowin.devIntroducing FastMCP 3.0 🚀Move fast and make things.

Jeremiah Lowin

@jlowin.dev

20 Jan

The new architecture lets us ship a massive number of features: 🎁 Custom providers like filesystems and remote APIs ✨ Per-component authorization 🏷️ Component versioning 🧠 And even skills over MCP...! Read the comprehensive feature guide here: www.jlowin.dev/blog/fastmcp...

jlowin.devWhat's New in FastMCP 3.0A comprehensive guide to every major feature

Jeremiah Lowin

@jlowin.dev

20 Jan

And by popular demand, we’ve polished the developer experience: ⚡ Servers support hot reload during development ⚡ Decorators now return callable functions (finally!) ⚡ Automatic threadpools for sync tools

Jeremiah Lowin

@jlowin.dev

20 Jan

There's A LOT here, but we've tried extremely hard to keep breaking changes minimal. Most users will not need to change their code at all. You can read the full upgrade guide here: gofastmcp.com/development/... Happy (context) engineering!

gofastmcp.comUpgrade Guide - FastMCPMigration instructions for upgrading between FastMCP versions