History
Origin
gRPC began inside Google. For more than a decade Google ran a single general-purpose RPC infrastructure called Stubby to connect the services behind its products, as described on the project's About page: "Google has used a single general-purpose RPC infrastructure called Stubby ... for over a decade" (https://grpc.io/about/). Stubby was tied tightly to Google's internal infrastructure and depended on no public standards, so it could not be released as is.
The arrival of SPDY, HTTP/2, and QUIC gave Google a way to rebuild that infrastructure on open standards. In March 2015 Google decided to build the next version of Stubby and make it open source; the result was gRPC (https://grpc.io/about/). The first public release used Protocol Buffers for serialization and HTTP/2 for transport (https://en.wikipedia.org/wiki/GRPC).
Timeline
| Year | Milestone |
|---|---|
| 2014 | GitHub repository grpc/grpc created (2014-12-08, per the GitHub API). |
| 2015 | gRPC announced and released as open source, built on Protocol Buffers and HTTP/2 (https://grpc.io/about/). |
| 2017 | Accepted into the CNCF as an Incubating project (2017-02-16, https://www.cncf.io/projects/grpc/). |
| 2026 | Active development on the 1.83 line; latest release v1.81.1 (2026-06-08), with v1.82.0-pre1 tagged. |
How it evolved
The public design choice that shaped gRPC was building on HTTP/2 rather than a bespoke protocol. HTTP/2 multiplexing, header compression, and streaming map directly onto gRPC's four call types (unary, server-streaming, client-streaming, bidirectional), and they let gRPC ride existing proxies and load balancers (https://grpc.io/about/).
Internally the project has been migrating its call machinery. The repository now carries two generations of the call stack side by side: the older callback-driven implementation and a newer promise-based one, both behind the same public C API. This is documented in src/core/call/AGENTS.md:31 and is the largest in-flight architectural shift in the codebase.
Where it stands now
gRPC remains a CNCF Incubating project and has not graduated (https://www.cncf.io/projects/grpc/). Releases come on a roughly six-week cadence; the HEAD documented here sits on the 1.83 development line. The maintainer roster in MAINTAINERS.md is dominated by Google employees, and governance rules are kept in a separate grpc/grpc-community repository. Observers have linked the project's strong single-vendor control to its long stay at Incubating status (https://news.ycombinator.com/item?id=36698723).