Changelog

When looking at the before and after screenshots has you scratching your head, click on a diff to open up the new focused full-screen modal. You can see everything that happened leading up to that diff, and rapid access to all our more advanced debugging tools such as HTML DOM snapshots, replays, etc.

We've spent a lot of April making test runs quicker. A few of the bigger pieces:

• Parallel base & head execution – head replays no longer wait for the base run to finish. You'll notice this even more on stacked PRs
• Session slicing – a single long session used to slow down how quickly we could share test run results. They're now sliced into shorter, replayable chunks, which gets more of your real user flows into every test run without dragging runtime up
• Faster startup – replay workers have been rearchitected so less time is spent waiting for your test run to start executing
• Faster uploads – S3 transfer acceleration is on for recorder, asset, and container uploads
• More resilient runs – one bad chunk no longer fails the whole test run; we will automatically retry

Visual diffs are great, but "did this PR make the app slower?" is a question we keep hearing. Replays now capture real performance signals - memory usage, CPU pressure, TTI and more. Pair that with hardware-pinned benchmarking (so you're comparing apples to apples across instance generations) and you can start spotting perf regressions on the same PR-by-PR cadence as visual ones.

This is early and we're looking for design partners to shape it. If perf regressions are a thing your team cares about, let us know and we'll get you set up.

The HTML diff viewer now surfaces React component names (resolved through your source maps), so you can tell what component you're looking at without playing detective.

• 🔀 Session extension (Beta) – adds coverage to your project by intelligently mutating session data from network traffic, feature flags, etc. to hit uncovered paths. Let us know if you'd like us to enable this feature for your project.
• ✅ Describe Tested rolls out to everyone – The PR coverage callout that tells you whether Meticulous actually exercised the code your PR touched is now on for all projects, thank you to everyone who used the beta feature!
• 🪪 Reader role + project-scoped SSO claims – New read-only role and meticulous_role / meticulous_projects SSO token claims so you can give people access to specific projects without handing over the whole org.
• 📋 Copy as prompt – One-click copy of a diff (with screenshot URLs and React component-source metadata) as an LLM-ready prompt - paste into your Claude Code to give it context on what you want to fix.
• 🧰 Broader recorder coverage – Better fidelity for Rive animations, navigator.locks, SubtleCrypto.digest, PressureObserver, ReportingObserver, tRPC batched/streaming requests and batched GraphQL.
• 🗺️ Unminified Stack Traces – Error reports in your application now display exactly where in the application they occurred, not just that they occurred!
• 🤖 Agentic Skills – we're continuing to iterate on our agentic skills library. Let your agent execute Meticulous against its local changes and iterate on the results, e.g. "Upgrade React major version and then use Meticulous to iterate until you remove all unexpected visual differences".

We've built a new dashboard that gives you a bird's-eye view of how Meticulous is performing across your project: track code coverage trends, test run execution time, user engagement and potential bugs that Meticulous has flagged. You can access it from your Meticulous project page.

We've rebuilt the timeline sidebar to make the events leading up to a diff much more intuitive, so you're not scrolling through 47 duplicate rows wondering what went wrong in this test run or your life. This is just the beginning of our planned design work to better surface relevant context around each visual difference, so let us know what is and isn't working for you.

When a test failure has you scratching your head, and even the newly redesigned inspect panel cannot save you, there is now a "Debug with AI" button right in the Meticulous UI. It sets up an AI-assisted debugging workspace, so you can investigate what went wrong without having to piece together CLI commands. Think of it as pair-debugging with someone who already has all the context loaded. If you'd rather give agents direct access to your Meticulous test runs through the CLI, we recommend adding these new skills. We're going deep on agentic workflows - if you have thoughts on what would be most useful, we're all ears.

• 🔗 Combined PR Comments – If you have multiple Meticulous projects in one repo, results now appear in a single PR comment instead of cluttering your PR thread.
• 🧪 Smarter Network Patching – Several improvements to how we match and repair API responses, meaning fewer false diffs caused by stale mocks.
• ⚙️ Self-Serve Network Settings – Request and response size limits (and other settings that used to require contacting us) are now available in your project settings.
• 🧵 Test Runs Threaded by PR – The project test runs page now groups runs by pull request, so older runs collapse under the latest instead of filling your screen.
• 💨 Session Acceleration – We're actively working on making Meticulous test runs faster.

Meticulous now runs reliably against complex server-side rendered apps and custom build pipelines, without preview URLs or the tunnel. You can now upload your app as a Docker container for Meticulous to run test replays against. This gives teams a more reliable, faster, and cheaper way to run Meticulous. You should only switch if you're not using the static asset upload method. See docs for more info.

We've redesigned the content on the test run landing page to provide more helpful information including: sessions run, approvals, an updated "how to review" section, and keyboard shortcuts for our power users.

• 🖼️ Iframe Network Recording – Network requests inside iframes are now captured, improving coverage for apps with embedded content.
• 🌈 Timeline Tab Improvements – Better colour scannability and filtering in the replay timeline view.
• 🔍 Improved Divergence Details – Redesigned divergence information UI with clearer context on what changed and why, making it easier to understand diffs at a glance.
• 🔗 Stable Diff Links – We've updated our selected difference URL format to make sharing differences with other users smoother.
• ⚡ Faster Session Repair – Core engineering work that significantly improves the speed of network patching.
• 🔐 OAuth JWT Authentication – Added OAuth JWT to make Meticulous CLI commands easier to access.

We've re-designed the action menu system with a cleaner, more consistent design. With even more actions, we've supercharged your ability to access platform functionality more easily, such as sharing differences, reporting flakes, displaying context of difference and more.

You can now view code coverage for individual replays - not just the entire test run. Use the action menu on any thumbnail and select "View Code Coverage" to see exactly which lines of code were exercised during that specific user flow.

• ✅ Filter by Approval State – We are continuing to improve the approval process, now allowing you to filter out differences you've already reviewed in prior test runs.
• 🏷️ Descriptive User Flow Titles – AI-generated session descriptions now appear as user flow titles when grouping by flow, instead of "User flow 1, 2, 3...".
• 📜 Diff Auto-scroll & Share – Automatically scroll to selected diffs and easily share links to specific differences.
• 🤖 Improved AI Network Patching – Upgraded parsing engine for more reliable mock generation.
• ⚡ Faster Large Test Runs – Significant frontend performance improvements when reviewing test runs with 1000+ differences.
• 🖼️ Better Iframe Handling – New replay engine to handle iframes to reduce flakiness in apps with embedded content.
• 🔧 Improved CI Setup UX – Clearer CI integration setup flow with better guidance on configurations for setting up new projects.
• 🔡 New Font – Better default font choice that improves the visual density and appearance of our UI.

We compute which of your code edits were not tested by Meticulous and leverage AI to summarise this for you. The new view accessible from the test run screen lets you see if any functionality affected by your PR was not able to be tested by Meticulous.

We've made huge strides in our approach to network patching, and we're introducing an improved engine to detect stale network mocks and synthetically generate new network mocks based on more recent session traffic.

• ⚡️ Improved Low Bandwidth Experience – on the test run screen, we've modified image loading patterns for an improved experience on bad connections.
• 🎯 Clearer Divergence Details – when Meticulous clicks on different elements in a user flow, you'll now see a much clearer description of what happened.
• 🔊 AudioContext mocking – better handling of audio-based functionality.
• ☁️ Faster cloud replays – infrastructure improvements for quicker test execution.