Yaak is an open-source, local-first desktop API client for testing and building APIs. It supports REST, GraphQL, gRPC, WebSocket, and Server-Sent Events. The project comes from Gregory Schier, the developer who originally created Insomnia, and it reflects a clear stance: your requests live on your machine, in plain-text files, with no mandatory account and no cloud lock-in.
If you have searched for “Yaak” and landed on maps of rural Montana, you are in the wrong place. Yaak, Montana is an unincorporated community near the Canadian border. This article is about Yaak the API client, available at yaak.app. Same word, different thing entirely.
This guide explains what Yaak is, where it came from, how it stores your work, which protocols it speaks, and who it fits. We will keep it factual and finish with where a design-first platform like Apidog fits alongside it.
The origin story: built by the creator of Insomnia
Yaak’s backstory matters because it shapes the product. Gregory Schier built the original Insomnia, one of the most loved API clients of the 2010s. Kong later acquired Insomnia, and over time the tool shifted toward a do-everything, account-required model that many long-time users disliked.
Yaak is Schier’s second attempt, built with the benefit of hindsight. It is independent, open source under the MIT license, and developed without venture-capital pressure. The roadmap is shaped through public feedback rather than growth dashboards.
That history explains the design choices below. Yaak is not trying to be a platform. It is trying to be a fast, private client that respects your files and your time.
Local-first and Git-native by design
The defining trait of Yaak is where your data lives. Everything stays on your filesystem. There is no required login, no telemetry, and no forced cloud sync. Your workspaces, environments, and requests stay on your machine unless you choose to share them.
This is what “local-first” means in practice. The app works fully offline. You own the data, and you decide if it ever leaves your computer.
Yaak also stores collections as Git-friendly plain-text files. That is a meaningful difference from clients that hide your work inside an opaque database or a remote workspace. Because the files are readable text, you can commit them to a repository, review changes in a pull request, and resolve merge conflicts like any other code.
For teams that already live in Git, this is a clean collaboration model. You do not pay for a separate sync service. Your API requests version alongside the code that calls those APIs. If you want to compare this approach with other tools that work the same way, see our overview of Git-native API clients.
Local-first also tends to mean fast. Yaak is built with Tauri, Rust, and React, which keeps the desktop footprint small and the interface responsive. There is no round trip to a server for basic actions.
Which protocols Yaak supports
Yaak is not limited to plain REST. It handles the protocols modern backends actually use.
- REST and HTTP. The core use case. Build requests, set headers, manage bodies, and read responses.
- GraphQL. Write queries with schema awareness instead of hand-typing raw payloads.
- gRPC. Call gRPC services directly, useful for microservice and internal-platform work.
- WebSocket. Open a connection and exchange messages for real-time features.
- Server-Sent Events (SSE). Stream events from the server over a single HTTP connection.
On the authentication side, Yaak covers the common schemes you need for real APIs, including OAuth 2.0, AWS Signature v4, JWT, and custom auth setups. It also imports from Postman, Insomnia, OpenAPI, Swagger, and curl, so moving existing work in does not start from zero.
That protocol range puts Yaak in the same conversation as other full-featured REST API clients, with the added benefit of running offline by default.
The companion CLI for automation and agents
A GUI client is only half the story for many workflows. Yaak ships a companion CLI that runs your saved requests outside the desktop app.
This matters for two situations. The first is continuous integration. You can run requests from a pipeline without opening the GUI, which is the usual pattern for API checks in CI. The second is AI-assisted development. The CLI is built to be agent-friendly, so coding agents can drive your saved requests programmatically.
Yaak previously shipped an experimental MCP (Model Context Protocol) server plugin so assistants like Claude and Cursor could inspect and send requests. The Yaak team has since deprecated that MCP plugin and now points agent-driven workflows at the CLI instead. If you read older posts that mention Yaak’s MCP server, that is the context: the CLI is the current recommended path.
The takeaway is that Yaak is not GUI-only. The same requests you build by hand can run in a script, a pipeline, or an agent loop.
Pricing and licensing
Yaak’s licensing follows a clear personal-versus-commercial split, and the open-source side stays open.
The source code is MIT licensed. You can view, modify, build, and run it yourself for any purpose. The license terms apply to the prebuilt binaries, not the code.
Yaak is free for personal use. A paid license is only required when you use it at work, meaning revenue-generating or work-related activity. The app offers a 30-day trial on first launch with no credit card. Paid plans cover individuals and businesses, with per-seat business pricing for teams. Prices change over time, so check yaak.app/pricing for the current numbers before you commit.
This model is friendly to solo developers and students, who can use a fully featured, offline client at no cost.
Who Yaak is for
Yaak suits a specific kind of developer well. You will like it if you want a fast desktop client that works offline, you do not want to create an account to send a request, and you prefer your requests stored as files you can put in Git.
It is a strong fit if privacy is a priority. No telemetry and no cloud sync means nothing about your requests leaves your machine by default. It also fits engineers burned by past tools that pushed mandatory accounts or cloud features they never asked for.
If you are evaluating options in this space, Yaak belongs on any honest list of Postman alternatives and offline API clients. It is also a natural comparison point against the original Insomnia, which our Apidog vs Insomnia breakdown covers, and against Bruno, another local-first, Git-native client we compare in Apidog vs Bruno.
Where a design-first platform fits alongside it
Yaak is built to be a lean, local, Git-native client. That is its strength, and it does that job well. It is deliberately not a full API lifecycle platform, and it does not try to be.
If your work spans design, testing, mocking, documentation, and team collaboration in one place, that is a different shape of tool. Apidog is an all-in-one API platform that covers the contract end of the lifecycle. You design APIs in a visual OpenAPI editor with branch support, run automated test scenarios with visual assertions, generate dynamic mock servers with no code, and publish interactive documentation. Teams work in shared workspaces with real-time sync, and the Apidog CLI runs saved test scenarios in CI.
Apidog runs as a desktop app on Windows, Mac, and Linux, plus a web app, and supports REST, GraphQL, gRPC, WebSocket, SOAP, and Socket.IO. It is not a CMS, an API gateway, or a load generator. It owns the API-quality layer: designing, testing, mocking, and documenting the contract.
The honest way to frame the choice is by what you need. Pick Yaak when you want a fast, offline, file-based client with zero cloud dependency. Reach for a platform like Apidog when design-first workflows, mocking, generated docs, and team collaboration belong in the same tool. Both can coexist in one engineering org.
FAQ
Is Yaak free?
Yes, for personal use. Yaak is free for personal use, and the source code is open under the MIT license. A paid license is required for commercial use at work. Check yaak.app/pricing for current personal and business tiers.
Is Yaak open source?
Yes. Yaak is open source under the MIT license. You can view, modify, build, and run the source yourself. Licensing terms apply to the prebuilt commercial binaries, not to the code itself.
Who created Yaak?
Gregory Schier created Yaak. He is the developer who originally built Insomnia before Kong acquired it. Yaak is his independent second take on a fast, private, local-first API client.
What protocols does Yaak support?
Yaak supports REST and HTTP, GraphQL, gRPC, WebSocket, and Server-Sent Events. It also handles common auth schemes like OAuth 2.0, AWS v4, and JWT, and imports from Postman, Insomnia, OpenAPI, and curl.
Does Yaak work offline?
Yes. Yaak is local-first and works fully offline. Your requests live on your filesystem with no mandatory account and no telemetry, so nothing leaves your machine unless you choose to share it. For more options, see our list of free API clients.
Is Yaak related to Yaak, Montana?
No. Yaak, Montana is a place near the Canadian border. Yaak the API client is software from yaak.app. They share a name and nothing else.