Google open-sources SDK generation toolkit after previous vendor shuts down abruptly

Google has partnered with Speakeasy to build SDKs for its Interactions API and, in the same move, released Speakeasy's entire code-generation suite — OpenAPI generator, agent CLIs, and MCP servers — under the AGPLv3 license. The decision was forced by events in May 2026, when Google's existing SDK vendor was acquired and announced an immediate shutdown just before Google I/O and the stable launch of the Interactions API.

The sudden closure exposed the risk of depending on proprietary, closed generators. Google concluded that if the industry relies on OpenAPI to define interfaces, the tools that translate those specifications into client libraries, CLIs, and agent tooling need to be open infrastructure. The migration to Speakeasy was executed on a compressed timeline with two priorities: minimize disruption for developers and avoid breaking changes.

The engineering work was meticulous. Teams aligned type definitions across every target language, preserved a strict error hierarchy and streaming behavior, and integrated the generator directly into Google's monorepo and internal build system. At Google DeepMind, engineers stress that while AI is being woven into development workflows, converting formal API specs into multi-language SDKs demands full determinism and type safety. The solution pairs a fast, deterministic generator core with "Antigravity" agents that accelerate the custom portions of each SDK.

What once required a team of engineers to maintain hand-written generators now runs on a single engineer. The same configuration drives the client pipeline across six targets; three SDKs have already shipped — covering the Interactions API, Agents API, and Webhooks API — and all are available today through the `google-genai` package.

The generator itself carries an AGPLv3 license. In practice, developers can run it in their own development or CI pipelines while retaining full ownership of the generated code; the resulting SDK may be released under MIT, Apache 2.0, or any license of their choosing. Only modifications to the generator's compiler trigger the AGPL's requirement to share improvements with the community. The complete source is on GitHub, and any developer can point it at their own OpenAPI specs to produce client libraries, CLIs, or MCP servers.