Launch HN: Momentic (YC W24) – Agents that catch bugs by using your app

wuweiweiwu — Mon, 2 Nov 2026 17:05:25 +0000

Catch bugs before they ship.

Mo is an AI QA engineer that tests your app end to end. Verify critical flows and find bugs from a prompt.

Tests created 77,813

Test runs executed 70,607,819

Changes verified 339,166

PRs verified 80,290

Auto-heals 8,932,104

Bugs caught 117,010

Tests created 77,813

Test runs executed 70,607,819

Changes verified 339,166

PRs verified 80,290

Auto-heals 8,932,104

Bugs caught 117,010

Tests created 77,813

Test runs executed 70,607,819

Changes verified 339,166

PRs verified 80,290

Auto-heals 8,932,104

Bugs caught 117,010

Trusted in production by teams shipping every day.

"Our team's experience with Momentic has been great. Setting up tests is simple and the developer experience has been fantastic."

Erdem

Head of Developer Experience, Notion

"Having E2E QA be part of the development process, run this fast (6.3x parallel), and at this scale (for every single pull request) is a true dream. Seriously, a green CI now has a measurable impact on my sleep quality."

Glavin

Founding AI Engineer, Coframe

"Momentic makes it 3x faster for our team to write and maintain end-to-end tests. Startups win by shipping faster and better, and Momentic enabled us to do exactly that."

Alex

CTO, GPTZero

"I just ran our first automated eval across 110 prompts. This would have taken well over an hour manually — I kicked it off in 5 seconds and it was done in 14 minutes. HUGE for us."

Mike

Engineering Manager, Runway

"I love working with Momentic. Especially after having years of previous experience in QA, it feels like riding a bike, except the bike is a supercharged electric one!"

Anna

Senior Productivity Engineer, Webflow

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Code moves faster. Verification has to keep up.

Coding agents have made it dramatically faster to build software. The bottleneck is now knowing it works. Verification belongs in the agent loop. Agents need evidence from the app itself to verify that their changes deliver the intended behavior.

Explore

The agentic quality platform.

Write the user flows you need to verify. Momentic runs the tests against your app. Reuse successful AI actions and review proposed repairs as the app changes.

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Knows how your product works

Add terminology, expected behavior, and test guidance to the Knowledge base. AI-assisted steps look up relevant entries as they run.

PRODUCT CONTEXT AT EACH AI STEP

Keep tests working as the UI changes

Momentic finds controls again when the UI changes during a run. Permanent healing proposes a test-file repair for you to review.

RUNTIME RECOVERY AND REVIEWED REPAIRS

Verify changes with your coding agent

Give your coding agent the changed flow. It can use MCP to author a test, check it in a live session, and save the YAML alongside your code.

TESTS REVIEWED WITH THE CODE

See why a test failed

Inspect the failing step, screenshots, and traces. Classify failures as application bugs, test flakiness, or environment issues.

STEP-LEVEL FAILURE EVIDENCE

Verify before you merge or deploy

Run the CLI in your CI job. Use its exit code as a required check before merging or deploying.

CLI EXIT CODES FOR CI CHECKS

Verification from your editor to CI.

Define what matters. Let Momentic verify it.

Write steps and assertions in plain-English YAML.
Review and version the tests in your repository.

01 / author

Write tests in plain English

Describe a user flow and its expected result in plain English. Keep the steps and assertions in YAML files your team and coding agent can review.

02 / run

Run locally and in CI

Use the CLI to check the app you're changing. Run the same tests in CI before the next merge or deploy.

03 / triage

Find the root cause

See which step failed and inspect its screenshots and traces. AI triage investigates the cause and proposes a test repair for you to review.

04 / heal

Auto-heal as your product evolves

Momentic finds controls again when the UI changes. Permanent healing proposes test-file edits for review. Apply the diff and rerun to check the result.

Learns how your product works.

Describe your product’s terminology, business rules, and expected behavior in the Knowledge base. Agents use that context to choose actions and check outcomes.

Knowledge base

Give agents the product rules they need to check a flow.

App graph

Maps screens and user flows seen during test runs.

Review new guidance

Review session suggestions before adding them to the Knowledge base.

Loved by engineering teams.

“Momentic gave us a fast and reliable way to validate Poe.com's AI responses, even when they weren't deterministic.”

Momoko F. Head of Product Operations, Quora

30 min

daily test execution, down from 7 hours

500+

manual test cases replaced

100%

critical tests created in one month

Read the full story

Bugs caught by Momentic

Examples of application failures found by Momentic, with the affected flow and its impact.

117,010 before production

Detected ON A FEATURE BRANCH

New-device 2FA prompt skipped

At a consumer fintech app, a login routing change bypassed the new-device verification step.

Impact

A security checkpoint was silently skipped.

Detected BEFORE RELEASE

Page creation flow broken on mobile

On mobile, keyboard auto-dismissed when creating a new page, breaking content flow.

Impact

Silent friction in the core creation flow.

Detected IN STAGING

Driver ETA stuck on 'calculating'

A dependency update on a large rideshare app caused the live ETA subscription to silently fail after a ride was booked.

Impact

Riders never saw an arrival estimate.

Detected BEFORE DEPLOY

Scheduling availability displayed incorrectly

Incorrect display and logic in the calendar scheduling view.

Impact

Wrong availability shown to users.

Detected IN CI

Timer reset when the screen locked

At a leading wellness app, an iOS lifecycle change reset the active sleep timer the moment the phone locked.

Impact

Audio sessions ended mid-playback overnight.

Detected 8 MIN BEFORE DEPLOY

Saved cards dropped at checkout

At a top food-delivery marketplace, a payment-form refactor stopped pre-filling saved cards, forcing manual re-entry to pay.

Impact

Returning users abandoned checkout on mobile.

Detected IN A NIGHTLY RUN

Filters cleared when paginating results

At a popular online retail marketplace, moving to page two reset every active category and price filter.

Impact

Shoppers lost their refined search results.

Detected BEFORE MERGE

Valid promo codes rejected at the final step

At a large online travel marketplace, a validation change rejected multi-segment promo codes on the last checkout step.

Impact

Discounts failed and carts were abandoned.

Detected PRE-RELEASE

Wrong subtitle language on first play

At a major streaming platform, a locale-detection bug auto-selected the wrong subtitle track on initial playback.

Impact

Wrong-language captions at session start.

Detected BEFORE RELEASE

Legacy API issues exposed

12 bugs caught in one day. Exposed legacy API issues that would have shipped undetected.

Impact

Risked shipping regressions into major release.

Verify what you ship.

Changelog

Mo is generally available

Mo is out of beta. Start a session from your coding agent, the app, a PR comment, or the qa CLI. A separate agent reproduces each functional bug before Mo reports it.

QA Bench

We graded Mo, Codex, Claude Code, and Devin on 20 areas of Gitea, Metabase, Twenty, and Saleor. With 60 minutes per area, Mo found about 269 labeled bugs. The next best agent found about 86.

momentic.ai

Launch HN: Momentic (YC W24) – Agents that catch bugs by using your app

Catch bugs before they ship.

The agentic quality platform.

Define what matters. Let Momentic verify it.

Write tests in plain English

Run locally and in CI

Find the root cause

Auto-heal as your product evolves

Learns how your product works.

Knowledge base

App graph

Review new guidance

Bugs caught by Momentic

New-device 2FA prompt skipped

Page creation flow broken on mobile

Driver ETA stuck on 'calculating'

Scheduling availability displayed incorrectly

Timer reset when the screen locked

Saved cards dropped at checkout

Filters cleared when paginating results

Valid promo codes rejected at the final step

Wrong subtitle language on first play

Legacy API issues exposed

Verify what you ship.

Changelog

Mo is generally available

QA Bench