What is Yaak used for?

Yaak is a fast, privacy-focused desktop API client for REST, GraphQL, gRPC, WebSocket and Server-Sent Events, built with Tauri. It is a good fit for teams leaving Postman or Insomnia, and testing gRPC and WebSocket APIs.

Yes. Yaak is open source under the MIT licence. Its source code is on GitHub at mountain-loop/yaak and is written mainly in TypeScript.

Yes. Yaak is open source, so the software itself is free to use. Paid plans are also available, starting at $79 per seat per year.

What is Yaak an alternative to?

Yaak is an open-source alternative to Postman, Thunder Client, Kreya and Apifox. Other open-source alternatives to Postman include Bruno, Insomnia and Hoppscotch.

Is Yaak actively maintained?

Yes. The most recent commit to Yaak was on 28 September 2026, and the latest release is v2026.8.1, published on 23 September 2026. The project has 19k stars on GitHub.

Yaak: open-source alternative to Postman, Thunder Client

About Yaak

Yaak is a desktop API client for building, sending and inspecting requests to REST, GraphQL, gRPC, WebSocket and Server-Sent Events endpoints. It is built with Tauri, Rust and React and works offline-first, with no telemetry and no requirement to sync data to a cloud account.

Collections from Postman, Insomnia, OpenAPI, Swagger or curl can be imported. Responses can be filtered with JSONPath or XPath, and authentication supports OAuth 2.0, JWT and Basic Auth, with encrypted secrets that can be kept in the operating system keychain. Requests are grouped into workspaces and nested folders, and environment variables switch between dev, staging and production.

Workspaces can be mirrored to the filesystem so they can be versioned in Git or synced with a file-sync service. Template tags insert dynamic values such as UUIDs or timestamps, and themes and plugins allow customization. Yaak is MIT licensed, its repository topics position it as an alternative to Postman, Bruno and Insomnia, and development is funded by community-purchased licenses.

Key features

REST, GraphQL, gRPC, WebSocket and SSE requests
Import from Postman, Insomnia and OpenAPI
OAuth 2.0, JWT and Basic Auth support
Encrypted secrets with OS keychain storage
Workspaces mirrored to Git-friendly files
Environment variables and template tags
Plugins and custom themes

Good fit for

→Teams leaving Postman or Insomnia
→Testing gRPC and WebSocket APIs

Built with: TypeScript; Tauri; GraphQL
Tags: api-client; rest; graphql; grpc; websocket; tauri; postman-alternative; desktop

Yaak: questions and answers

What is Yaak used for?: Yaak is a fast, privacy-focused desktop API client for REST, GraphQL, gRPC, WebSocket and Server-Sent Events, built with Tauri. It is a good fit for teams leaving Postman or Insomnia, and testing gRPC and WebSocket APIs.
Is Yaak open source?: Yes. Yaak is open source under the MIT licence. Its source code is on GitHub at mountain-loop/yaak and is written mainly in TypeScript.
Is Yaak free?: Yes. Yaak is open source, so the software itself is free to use. Paid plans are also available, starting at $79 per seat per year.
What is Yaak an alternative to?: Yaak is an open-source alternative to Postman, Thunder Client, Kreya and Apifox. Other open-source alternatives to Postman include Bruno, Insomnia and Hoppscotch.
Is Yaak actively maintained?: Yes. The most recent commit to Yaak was on 28 September 2026, and the latest release is v2026.8.1, published on 23 September 2026. The project has 19k stars on GitHub.