Google and Speakeasy open source OpenAPI client generator suite

Google worked with Speakeasy to build the new Google GenAI SDKs for its Interactions, Agents and Webhooks APIs. The effort came after the SDK generation provider Google had been using was acquired and announced it would shut down in May 2026. Google says that episode showed closed-source generators carry platform risk, and it argues that the tooling which compiles OpenAPI definitions into client libraries should be open.

Google moved its client libraries to Speakeasy's generator in place, aiming to avoid breaking changes for developers. The work meant aligning type definitions across languages, keeping error hierarchies and streaming behavior intact, and integrating the generator into Google's internal monorepo and build system. Google says the setup now covers six targets, three of them released, with roughly one engineer maintaining it.

Speakeasy is releasing its OpenAPI client suite under AGPLv3. It includes a multi-language generator for Python, TypeScript, Go, Java, C#, PHP and Ruby libraries, with static typing, server-sent events streaming, retries and pagination. It also includes an agent-native CLI generator that compiles standalone binaries, and a documentation MCP server generator that turns OpenAPI specs and markdown docs into a Model Context Protocol server.

Teams that generate clients from OpenAPI specs can run the generator in their development or CI pipelines and keep ownership of the output under their own license, such as MIT or Apache 2.0. Changes to the generator compiler itself stay open to the community under the AGPL, which matters for anyone planning to patch it. Agents can also get generated CLIs and MCP servers that query current schemas, which reduces reliance on outdated method guesses.