head to head · open source
OpenAPI-Specification vs grpc-gateway
OpenAPI-Specification has 31,215 GitHub stars, 9,156 forks, 80 open issues and last shipped 7 days ago. grpc-gateway has 20,001 stars, 2,409 forks, 149 open issues and last shipped yesterday. OpenAPI-Specification leads on adoption by 56% (31,215 vs 20,001 stars). OpenAPI-Specification is written in Markdown under Apache-2.0; grpc-gateway is written in Go under BSD-3-Clause. OpenAPI-Specification has attracted 29% as many forks as stars, grpc-gateway 12%. grpc-gateway was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (openapi), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| OpenAPI-Specification | grpc-gateway | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 20K |
| License | Apache-2.0 | BSD-3-Clause |
| Written in | Markdown | Go |
| Last push | 2026-09-11 | 2026-09-17 |
| Forks | ⑂ 9.2K | ⑂ 2.4K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenAPI-Specification if
- You weight community size — 31K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Markdown
- You value the larger contributor base for long-term maintenance
pick grpc-gateway if
- You want the grpc-gateway feature set and don't need the biggest community
- You prefer the BSD-3-Clause license terms
- Your stack matches Go
- You evaluated both and grpc-gateway fits your workflow better
About OpenAPI-Specification
The OpenAPI Specification (OAS) is a community driven open specification hosted within the OpenAPI Initiative, a Linux Foundation Collaborative Project. It defines a standard, programming language agnostic interface description for HTTP APIs, represented in YAML or JSON. The specification lives in the HTTP API tooling ecosystem, alongside the tools, libraries, and implementations listed in the repository's implementations document. The project source is released under the Apache 2.0 license, and its GitHub repository has accumulated roughly 31,000 stars and 9,100 forks across 13 years of activity.…
read the full OpenAPI-Specification overview →
About grpc-gateway
gRPC Gateway is a plugin for protoc , the Google protocol buffers compiler. It reads protobuf service definitions and generates a reverse proxy server that translates a RESTful HTTP API into gRPC. The generated server follows the google.api.http annotations attached to those service definitions, so a single set of protobuf services can be exposed in both gRPC and RESTful style at the same time. It lives in the gRPC ecosystem, is written in Go, and is distributed under the BSD 3 Clause license.
read the full grpc-gateway overview →
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Frequently asked questions
Is OpenAPI-Specification or grpc-gateway more popular?
OpenAPI-Specification has 31,215 GitHub stars and grpc-gateway has 20,001. OpenAPI-Specification has the larger community by that measure.
Are OpenAPI-Specification and grpc-gateway free?
Both are open source. OpenAPI-Specification is licensed under Apache-2.0 and grpc-gateway under BSD-3-Clause. Neither carries a licence fee.
What is the difference between OpenAPI-Specification and grpc-gateway?
OpenAPI-Specification is written in Markdown and grpc-gateway in Go. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, OpenAPI-Specification or grpc-gateway?
Choose OpenAPI-Specification if you want the larger community (31,215 stars) or its Apache-2.0 licence terms. Choose grpc-gateway if its feature set, stack or BSD-3-Clause licence fits better. Both are self-hostable.