Idea checked
an open source alternative to Postman for API testing
This market is crowded and already has a large open-source winner, so a new Postman alternative needs a sharper niche than just being open source.
Confidence: high — There is a lot of real signal here: multiple maintained competitors with star counts, a few first-hand complaints, and several usage-heavy Postman-related packages. The main uncertainty is whether there is still room for a broad new entrant.
- hackernews 14
- github 20
- githubissues 1
- intent 3
- stackexchange 6
- registries 16
- tavily 7
- devto 10
Interest over time From data
Hacker News stories mentioning alternative postman testing, by year — 10 in total, currently rising.
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
This counts discussion on Hacker News, not global search demand. For developer tooling the two move together; for a local service business they do not.
Who is already building this From data
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Hoppscotch is the biggest visible open-source competitor here, with 79,944 stars and a recent push on 2026-07-30; it positions itself as an open-source alternative to Postman and Insomnia, with web, desktop, CLI, offline, on-prem, and cloud options.
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Bruno is also very large, with 46,071 stars and a recent push on 2026-07-31; it is explicitly described as a lightweight open-source alternative to Postman and Insomnia.
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Yaak had 153 HN points and 61 comments in a 2025-02-26 launch thread; the founder said it is a Postman alternative aimed at people who just want an API client, not mocking, testing, or spec design.
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Pororoca is much smaller at 662 stars, but it is still maintained, with a last push on 2026-06-03; it targets API testing and supports HTTP/2 and HTTP/3.
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ApiArc was launched on HN as a local-first Postman alternative, but only got 1 point in the signal, which suggests early traction is tiny compared with the leaders.
What people actually say From data
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One HN founder said Postman makes people navigate complex interfaces and manually construct requests, which is why they built OpenAstra with a chat interface.
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The Yaak founder said he had also built Insomnia before and now targets users who only want an API client, not a full suite of testing and spec tools.
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A 2024 HN thread about Insomnium said the project was archived and no longer actively maintained, after Kong bought Insomnia and added account requirements.
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A HN commenter on Postman and Insomnia alternatives said they were surprised those products have 'barely any moat' and that they had built their own API exploration and testing tool for their own use case.
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A Stack Overflow answer on free Postman alternatives recommended Bruno because it is open source, does not store your data, and uses your file system so you can interact directly with git.
People asking to be sold to From data
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A founder said they built OpenAstra because existing tools like Postman force complex interfaces and manual request construction, which is a direct complaint about the current workflow.
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The ApiArk founder said they were tired of Postman 'eating 800 MB of RAM,' requiring a login, and storing API keys on someone else's cloud.
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The Insomnium thread says users wanted an offline-only Postman alternative that did not need account creation or online connectivity.
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The Bruno recommendation specifically praises file-system storage and git-friendly workflows, which is a clear preference signal for local, versionable API testing.
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No one in the collected intent or issue signals clearly said they would pay for a new general-purpose Postman clone; the demand shown here is mostly for local-first, lightweight, or account-free tooling.
Where the opening is Model estimate
The model's read of the signals below — not something anyone measured.
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The clearest gap is not 'open source Postman' by itself; Hoppscotch and Bruno already cover that space with large, maintained projects.
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The signals do suggest room for a narrower product that is stricter about local-first storage, git-native files, and zero-login operation, because those themes keep appearing in complaints and competitor positioning.
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I did not see strong evidence for a gap around a new broad feature set like mocking, testing, spec design, and collaboration; those are already part of the existing competitors' positioning.
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There is no clear evidence from these signals that the market lacks a better UI alone; several products already compete on being lightweight or simpler.
How big the market might be Model estimate
The model's read of the signals below — not something anyone measured.
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This is a real market, not a curiosity: Hoppscotch has 79,944 stars, Bruno has 46,071 stars, and both are actively maintained.
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Usage around the Postman ecosystem is also large, with packages like postman-collection at 6,822,277 monthly downloads and postman-runtime present in npm, which suggests broad developer workflow dependence.
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The market seems sizable enough to support multiple open-source tools, but the highest-probability buyers are probably teams that care about local data, Git workflows, and avoiding vendor login or cloud storage.
What could go wrong Model estimate
The model's read of the signals below — not something anyone measured.
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The biggest risk is direct competition with Hoppscotch and Bruno, both of which already have strong brand recognition and active development.
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Another risk is feature creep: many users seem to expect more than request sending, but the existing tools already span testing, collections, offline mode, and collaboration.
- github hoppscotch/hoppscotch 2019-08-21
- hackernews Show HN: Yaak – An open source, Git-friendly desktop API client 2025-02-26
- hackernews Launch HN: Requestly (YC W22) – Network debugging proxy for web and mobile 2022-03-03
- tavily 6 Postman Alternatives for API Testing in 2026 | Autonoma AI
- tavily Powerful HTTP/API Clients: Alternatives to Postman
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A broad clone may be hard to differentiate because some competitor repos are already maintained and explicitly positioned as alternatives, while smaller ones keep appearing.
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The HN evidence also shows churn in this category: Insomnium was archived, which suggests users can move but projects can die quickly if they do not keep momentum.
What to do this week Model estimate
The model's read of the signals below — not something anyone measured.
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Do not build a generic 'open-source Postman' clone. Pick one wedge such as offline-first, git-native file storage, or zero-login local-only usage.
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Interview users who already complain about Postman RAM usage, cloud login, and key storage, because those are the strongest pain points surfaced in the signals.
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Study Bruno and Hoppscotch feature-by-feature before writing code, since they are the most credible live competitors in the dataset.
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Build a minimal desktop client that stores requests as plain files, supports import from Postman collections, and proves Git workflows end to end.
Domain names From data
Checked live against the registry, built from the subject of the idea rather than the first words of the sentence. A literal check is a fact; a brandable suggestion would be noise.
- opensource.com taken
- opensource.io available
- open.com taken
- getopen.com taken