Side by side

oapi-codegen vs Stainless

Both stand on api generation software. Which one you can start free with, which one lets you read the code, and what each costs once you pay.

oapi-codegen

Free plan LinuxSelf-hosted

oapi-codegen covers several Go server backends and client generation, with customization for generated output. Its OpenAPI 2.0 exclusion and version requirements are key limits to check.

Visit oapi-codegen

Stainless brings SDK generation, API documentation, and code-mode MCP servers together around OpenAPI. Check the Free plan limits and automatic trial enrollment, and note the on-premise hosting restriction.

Visit Stainless

The facts

	oapi-codegen	Stainless
Free plan	Yes	Yes
Open source	Not published	Not published
Runs on	Linux, Self-hosted	Linux, Mac, Web
Lowest paid plan	Free or on request	Free or on request
Plans published	1	1
Maker	Not published	Not published
Website	github.com	stainless.com
On api generation software	#9 of 25	#13 of 25

oapi-codegen: what it does well

Generates Go servers, clients, and HTTP models.
Supports OpenAPI 3.0 and 3.1.
Server boilerplate covers multiple Go frameworks.
Custom templates and OpenAPI extensions can shape output.
YAML configuration includes a JSON Schema.

What to know first

Does not support OpenAPI 2.0 (Swagger).
Building and installing requires Go 1.25 or newer.
Only the latest minor release receives active development support.
Some imported package internals and template overrides are unstable.

Stainless: what it does well

Generates SDKs from OpenAPI specifications.
SDKs include types, pagination, and retries.
Documentation stays in sync with the API.
Free plan includes email support.

What to know first

Free plan is limited to five generators and five seats.
Requires a GitHub account.
Code generation cannot be hosted on-premise.
Exceeding Free Plan terms triggers a 30-day paid-plan trial.

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