Move fast. Don't break things.

Assert is built to make code review fast and comprehensive.
PRs broken into reviewable units. Inline UI previews. Agent session context.

Code review interface showing a new comments sidebar with file tree, review overview, and TypeScript code comparison highlighting changes.

Change management

Make every change legible

Assert breaks pull requests down into a structure easier to review.

UI previews

Preview how changes will affect your product

View fine-grained before/after UI previews and when you see something wrong, comment directly on them.

Agent traces

Understand the intent of each change

View the prompts used in development to understand and debug changes to source code.

Move and refactor detection

We catch code moves and refactors to reduce noise. When a block disappears in one file and re-appears in another, Assert links the two sides and shows similarity so you can stop reading the same code twice. This feature is particularly useful for catching the needle in a haystack of mostly non-functional changes.

Hand comments off to your coding agents

Send any review comments straight to background agents to apply changes, or copy a framed prompt to paste into the assistant you already use. This is a great flow for when you want more control than full automation but need a more ergonomic experience than GitHub has to offer.

See who's already reviewing so you don't need to

Teammates currently viewing the same PR appear in the header, with an anonymous viewer count for everyone else. We're building features around designation for teammates and agents to save hours and tokens.

Comment rebasing after new pushes

When the PR moves underneath your in-progress comments, Assert rebases them to the latest commit. When there is a genuine conflict, we provide a guided flow.

Re-review mode

Get a focused view of only what changed since your last look. When a PR gets new commits, toggle a per-file delta view so you only re-review the lines that actually moved. Prior changes stay subtly highlighted for context.

Backed by world-class founders and developers

We're proud to have the support of industry leaders in OSS and AI.

Guillermo Rauch
Guillermo Rauch
Founder|Vercel
Vercel
Thomas Wolf
Thomas Wolf
Co-Founder|Hugging Face
Hugging Face
David Cramer
David Cramer
Co-Founder|Sentry
Sentry
Charlie Marsh
Charlie Marsh
Founder|Astral
OpenAIAstral
Andrew Milich
Andrew Milich
xAI
xAI
Rhythm Garg
Rhythm Garg
Co-Founder|Applied Compute
Applied Compute
Mehdi Ghissassi
Mehdi Ghissassi
Prev Head of Product|DeepMind
Google DeepMind
Assaf Elovic
Assaf Elovic
Prev Head of AI|Monday
Monday.com

and many others

Move fast. Don't break things.