--- title: Launch HN: Momentic (YC W24) – Agents that catch bugs by... description: Momentic's AI QA engineer, Mo, finds bugs in web, iOS and Android apps and writes repro steps for them. It then turns its own test runs into regression tests... canonical: https://daily.dev/posts/launch-hn-momentic-yc-w24-agents-that-catch-bugs-by-using-your-app-awtbgehyi twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Launch HN: Momentic (YC W24) – Agents that catch bugs by using your app | daily.dev og:description: Momentic's AI QA engineer, Mo, finds bugs in web, iOS and Android apps and writes repro steps for them. It then turns its own test runs into regression tests... og:url: https://daily.dev/posts/launch-hn-momentic-yc-w24-agents-that-catch-bugs-by-using-your-app-awtbgehyi og:image: https://api.daily.dev/og/posts/AwtbgehYI.png og:image:alt: Launch HN: Momentic (YC W24) – Agents that catch bugs by using your app og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Launch HN: Momentic (YC W24) – Agents that catch bugs by using your app **[Hacker News](https://daily.dev/sources/hn)** · 1 min read · 1 upvotes · 0 comments ## Summary Momentic's AI QA engineer, Mo, finds bugs in web, iOS and Android apps and writes repro steps for them. It then turns its own test runs into regression tests attached to every pull request. In one example, a login routing change at a consumer fintech app silently skipped the new-device 2FA verification step. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community take How the wider developer community reacted, aggregated from 1 discussion and 69 comments across hackernews (as of 2026-11-02). **TL;DR:** Discussion is dominated by skepticism about pricing, moat, and whether frontier models will soon make a custom harness unnecessary, though the founders' detailed, responsive replies on benchmarks and architecture won over some commenters. **Sentiment:** 15% positive · 40% mixed · 45% skeptical **The case for** - Several commenters appreciated the founders' transparent, detailed responses about benchmark methodology and tradeoffs. - Some found the exploratory-testing/regression-test pipeline concept compelling and well-suited to large, complex apps. - One commenter said the real-device and iOS support roadmap would be enough to make them pay. **The pushback** - Many questioned why pay more per bug than cheaper alternatives like Codex when precision is comparable or better. - Strong skepticism that there's any durable moat once frontier models or open-source harnesses catch up. - Complaints about lack of BYOK/BYO-API-key support, forcing another proprietary token subscription. - Some reported friction in onboarding, unclear auth setup, and an iOS build incompatibility bug. - One user raised a privacy concern about their email apparently being shared with Slack without clear disclosure. **By community** - hackernews (mixed): A vocal contingent pushed back hard on pricing, lock-in, and moat questions, but active, substantive founder engagement balanced the tone and resolved several concerns live. **Hottest debate:** Whether a specialized agent harness like Mo offers a lasting edge over cheaper general-purpose coding agents (Codex, Claude Code) as frontier models keep improving. **Open questions** - Will Momentic eventually support bring-your-own-key/agent so users can use existing model subscriptions? - How will the cost-per-bug tradeoff change as frontier models improve? - How does Mo's natural-language test format hold up in terms of vendor lock-in long term? **Highlights** > Hey! I'm Henry, one of the engineers working on Mo. You're looking at the right numbers, but the takeaway is slightly different from ours. The main thing we're trying to show is that Mo finds over 3x as many correct bugs in the same amount of time as the next-best QA agent. This is the main thing we optimize for since the worst thing you can do in QA is miss a real bug and ship broken code to prod. Currently, the tradeoff you make for that better recall is higher cost. I would say the precision is more or less comparable, but marginally lower. Obviously we'd love to be beating every other agent on all of these numbers, and we're actively working on it, but for now this is an honest and transparent look at how the tool is doing. Feel free to take a look at the full writeup for more detail! > — [momentichenry on hackernews · 1 comments](https://news.ycombinator.com/item?id=50340823) > Heyo! I'm Jeff, one of the co-founders here. Mira itself is for code review and does no e2e analysis. We actually automate your live web app or mobile app, so we're catching a whole class of issues that are just not possible with static analysis (is the button cut off in the UI? does your AI agent respond correctly? does the video render correctly? etc.) But to your general point, this benchmark is showing we are finding 3-5X more bugs than the best OSS performance out there right now. We did also try it on tester army e2e and it underperformed Codex + Playwright MCP (this will make it in the benchmark soon). The "better" comes from custom agents and massively parallelized infrastructure. I'm not sure how many folks want to or even can self-host fleets of GPUs, browsers and Mac minis. We're happy for folks who can but our current offering is for those who want to find the most bugs with the least amount of effort. > — [jeffan on hackernews](https://news.ycombinator.com/item?id=50343991) > Thanks! I'm Jeff, one of the co-founders. 1. Mo generates its own test cases in natural language, but you can ask it to write Playwright and maintain it in your repository if you really want. We actually do have a regression testing product as well where tests are just natural language in your repository. For that product yes there is some vendor lock-in since this is a proprietary format that only our CLI translates into browser actions. But ultimately since it's natural language it's pretty portable :) 2. Mo is focused on exploratory testing and so is inherently non-deterministic. But the regression testing product has a ton of caching built into it that we've written about in the past (not just a single css selector). https://momentic.ai/blog/teaching-browser-agents-user-intent This is a big part of reliability and latency optimization, otherwise your CI would just hang for hours on any reasonable suite. 3. I would say the regression testing product was very much SDET/developer focused since it required you to have a codebase and use Git. Mo is meant to be super easy for anyone to onboard onto and lower the barrier to entry, so we're hoping we'll see more product owners, PMs, QA and even leadership use the product. But devs are always going to be our bread and butter, we ultimately tried to build the product we wanted to use ourselves. 4. We're optimized for recall (# of bugs you find in a given amount of time). The bench shows we find ~3-5X more bugs compared to Codex and Claude Code, with approx. the same precision. The service costs more than the raw harnesses for sure, but that's the all-in cost including our infra, parallel agents, etc. > — [jeffan on hackernews](https://news.ycombinator.com/item?id=50341212) > Hey I'm Jeff (one of the co-founders). That's fair feedback. We wrestled a lot with whether to support BYOA or open source the harness. Ultimately there was no configuration with off the shelf models that we were happy with performance-wise. A lot of the eng work that went into this came tuning custom agents from large datasets to do the "grunt work" like element grounding and visual understanding. Plugging in vanilla GPT6.1 Sol for every task into our harness just doesn't yield a pareto optimal result that makes sense as a standalone product (you are better off asking codex to test). That doesn't mean we won't eventually support byok, especially as OSS models catch up! We have our finger on the trigger there. > — [jeffan on hackernews](https://news.ycombinator.com/item?id=50340335) > Closed source, non self-hosted in 2026? Nah. What do you guys have that's better than a self-hosted, open source extensible QA AI tool like Mira? [1] https://miracode.ai > — [upmostly on hackernews · 1 comments](https://news.ycombinator.com/item?id=50343730) **Source threads** - [hackernews](https://news.ycombinator.com/item?id=50339913) · 100 points · 69 comments ## Similar posts on daily.dev - [Mo the AI QA, by Momentic](https://daily.dev/posts/mo-the-ai-qa-by-momentic-zne8hojdi) · Programming Digest · 1 upvotes · 0 comments - [Agentic Mobile Testing With e2e and agent-device](https://daily.dev/posts/agentic-mobile-testing-with-e2e-and-agent-device-00c7gyjaz) · Callstack Blog · 0 upvotes · 0 comments - [Quality Assurance Agent: Reimagining Software Quality with AI-Driven Autonomous Testing](https://daily.dev/posts/quality-assurance-agent-reimagining-software-quality-with-ai-driven-autonomous-testing-0dcl533yi) · LinkedIn Engineering · 0 upvotes · 0 comments --- Tags: [#ai-agents](https://daily.dev/tags/ai-agents), [#testing](https://daily.dev/tags/testing) [View this post on daily.dev](https://daily.dev/posts/launch-hn-momentic-yc-w24-agents-that-catch-bugs-by-using-your-app-awtbgehyi) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Launch HN: Momentic (YC W24) – Agents that catch bugs by using your app","url":"https://daily.dev/posts/launch-hn-momentic-yc-w24-agents-that-catch-bugs-by-using-your-app-awtbgehyi","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/launch-hn-momentic-yc-w24-agents-that-catch-bugs-by-using-your-app-awtbgehyi"},"datePublished":"2026-11-02T19:11:24.058Z","dateModified":"2026-11-02T22:18:54.067Z","description":"Momentic's AI QA engineer, Mo, finds bugs in web, iOS and Android apps and writes repro steps for them. 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