Yaak is a fast, offline-first desktop API client built by Greg Schier — the same engineer who created and sold Insomnia in 2019. We rate it 88/100: it is the most polished open-source Postman alternative we have tested in 2026, and the right pick for any developer who wants Insomnia's old UX without the cloud account or AI-feature bloat.

What is Yaak?

Yaak is a desktop API client for REST, GraphQL, gRPC, WebSockets, and Server-Sent Events. It is built by Mountain Loop Labs, the one-person company behind Greg Schier, who launched the original Insomnia in 2014 and sold it to Kong in 2019. The first commit landed on February 16, 2023, and the public 1.0 shipped in January 2024. The repo at mountain-loop/yaak currently sits at 18,498 stars and 741 forks under an MIT license, and the official site reports 122,000+ downloads.

What separates Yaak from Postman, Insomnia, and Bruno is its uncompromising local-first design: no required account, no telemetry, no cloud sync, no AI assistant trying to upsell you. Secrets are encrypted at rest and stored in your OS keychain, and workspaces can optionally be mirrored to plain-text JSON for Git or Dropbox versioning — the feature Insomnia removed and Postman never shipped properly.

Yaak desktop API client main interface showing a REST request workspace — Yaak's main workspace: clean three-pane layout with sidebar collections, request builder, and response inspector.

Key Features of Yaak

Five protocols, one workspace: Mix REST, GraphQL, gRPC, WebSocket, and Server-Sent Events requests in the same folder — something Postman charges enterprise tiers for.
Built with Tauri + Rust: The desktop binary is around 30 MB and starts in under a second on a 2020 M1 — Postman's Electron app is roughly 10× larger and notoriously slow.
Encrypted secrets and OS keychain: Sensitive values are encrypted with a workspace-level key and pulled from macOS Keychain, Windows Credential Manager, or libsecret on Linux.
Git-friendly workspaces: Toggle a workspace into plain-text mode and Yaak writes one JSON file per request — review collection changes in pull requests like any other code.
Agent-friendly CLI (2026.3): A new command-line interface lets coding agents like Claude Code or Cursor create, update, and execute requests programmatically, then read back the full response.
Imports from everywhere: Postman v2.1, Insomnia v4, OpenAPI 3, Swagger 2, and raw curl commands — tested against multi-megabyte real-world collections.
Authentication that works: OAuth 2.0 (with external-browser flow), OAuth 1.0a, AWS SigV4, JWT, NTLM, Basic, Bearer, API Key, plus a 1Password template function.

Yaak's agent-friendly CLI for coding agents like Claude Code and Cursor — The 2026.3 release added a full CLI — coding agents can now drive Yaak to send and inspect requests.

What Users Say About Yaak

Sentiment is unusually positive. On r/webdev and r/devops, top-voted threads call it “the Postman alternative that finally sticks” and praise the speed: developers report sub-second cold starts and instant request switching even on 500-request collections. Hacker News launch threads describe Yaak as “Insomnia how it should have been” and credit Greg's track record. Twitter/X testimonials from EGOIST, Tim Cole, and the founder of Bytebase echo the same theme: clean UI, no bloat, no AI nonsense.

The recurring complaints are honest. Reddit threads flag that real-time team collaboration is not built in — Yaak is local-first, so you collaborate via Git, not via a Postman-style cloud workspace. Some teams coming from Postman miss the built-in test-runner UI (Yaak supports request scripting via plugins, but it is not as discoverable). And the commercial license model trips people up: while the source is MIT and free for any use, the prebuilt commercial binaries cost $79/year per individual or $149/user/year for businesses.

Yaak Pricing

Yaak is dual-licensed: MIT source code that you can build and use yourself for free, plus paid commercial licenses for the official prebuilt binaries used at work.

Plan	Price	Best For
Personal (free)	$0	Hobby projects, learning, personal API testing.
Individual Annual	$79 / year	Solo developers using Yaak at work.
Individual Lifetime	$299 one-time	Pay once, all future updates, no renewal.
Business	$149 / user / year	Teams that need transferable licenses and priority support.

A 30-day commercial trial activates automatically the first time you launch the app — no credit card or signup. Yaak also offers 50% PPP discounts for residents of eligible countries.

Who Should Use Yaak?

Best for: Backend, mobile, and full-stack developers who already version code in Git and want their API collections to live alongside it. Privacy-conscious teams that refuse to send request payloads to a vendor cloud. Anyone who liked early Insomnia (2017–2019) and wants that feel back. Coding-agent users (Claude Code, Cursor, Aider) who want to script requests through the new CLI.

Not ideal for: Large enterprise QA teams that depend on Postman's cloud-based test runner, monitors, and mock servers, or non-technical users who need a hosted workspace with shared edit access.

Pros and Cons

Pros: ~30 MB binary with sub-second cold start; true offline-first with no telemetry; first-class Git-friendly plain-text mode; MIT-licensed source; built by the original Insomnia creator; monthly release cadence through 2025–2026.

Cons: No built-in cloud sync or real-time team workspaces; commercial license required for prebuilt binaries at work; test-runner UI is plugin territory; plugin ecosystem still young.

Alternatives to Yaak

The three direct competitors are Postman (cloud-first, feature-heavy, increasingly priced for enterprises), Bruno (also Git-friendly and open source, but rougher UX and narrower protocol coverage), and Insomnia (now Kong-owned, recently shifted toward forced cloud accounts). Hoppscotch is a free web-based option but lacks Yaak's gRPC and authentication depth.

Verdict: Is Yaak Worth It?

Yes — if you have ever felt that Postman or Insomnia stopped serving you and started serving their growth team, Yaak is the obvious move. The $79/year individual license is fair for what you get, and the lifetime $299 plan is the right pick if you expect to use it for more than four years. We rate it 88/100; the missing points are about the lack of cloud collaboration and a still-young plugin ecosystem — problems Yaak's public roadmap is openly tackling.

Frequently Asked Questions

Is Yaak free?: Yaak is free for personal use, and the source code is MIT-licensed (you can build and use it yourself for any purpose). Prebuilt commercial binaries require a license: $79/year individual, $299 lifetime, or $149/user/year for business teams. A 30-day commercial trial is included with no credit card.
What platforms does Yaak support?: Yaak runs natively on macOS (Apple Silicon and Intel), Windows, and Linux (deb, rpm, AppImage). It is a Tauri-based desktop app — there is no web version.
Is Yaak open source?: Yes. The full source is MIT-licensed at github.com/mountain-loop/yaak with 18,498+ stars as of April 2026.
How does Yaak compare to Postman?: Yaak is offline-first, ~10× smaller, and has no required account or telemetry. Postman has a larger plugin marketplace, hosted monitors, mock servers, and team-wide cloud sync. If your collections must live in a cloud workspace, stay on Postman; if you are happy versioning them in Git, Yaak is the better daily driver.
Who built Yaak?: Greg Schier — the engineer who created Insomnia in 2014 and sold it to Kong in 2019. Yaak is built under his company Mountain Loop Labs and funded by license sales and GitHub Sponsors, not VC.

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