head to head · open source
openapi-generator vs grpc-gateway
openapi-generator has 26,745 GitHub stars, 7,674 forks, 5,751 open issues and last shipped yesterday. grpc-gateway has 20,001 stars, 2,409 forks, 149 open issues and last shipped yesterday. openapi-generator leads on adoption by 34% (26,745 vs 20,001 stars). openapi-generator is written in Java under Apache-2.0; grpc-gateway is written in Go under BSD-3-Clause. openapi-generator has attracted 29% as many forks as stars, grpc-gateway 12%. openapi-generator was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 3 topic tags (openapi, rest-api, restful-api), 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-generator | grpc-gateway | |
|---|---|---|
| GitHub stars | ★ 27K | ★ 20K |
| License | Apache-2.0 | BSD-3-Clause |
| Written in | Java | Go |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 7.7K | ⑂ 2.4K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick openapi-generator if
- You weight community size — 27K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Java
- 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-generator
OpenAPI Generator is an Apache 2.0 licensed Java tool that generates API client libraries, server stubs, documentation, and configuration automatically from an OpenAPI Specification, and it is built for development teams that keep a machine readable API description and want generated code to stay in step with it.
read the full openapi-generator 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-generator or grpc-gateway more popular?
openapi-generator has 26,745 GitHub stars and grpc-gateway has 20,001. openapi-generator has the larger community by that measure.
Are openapi-generator and grpc-gateway free?
Both are open source. openapi-generator is licensed under Apache-2.0 and grpc-gateway under BSD-3-Clause. Neither carries a licence fee.
What is the difference between openapi-generator and grpc-gateway?
openapi-generator is written in Java 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-generator or grpc-gateway?
Choose openapi-generator if you want the larger community (26,745 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.