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Backed by Y Combinator

ClaudeCodexCursorDevinCopilotClaude writes your code.Canary breaks it.

An army of adversarial agents hunts, breaks, simulates and verifies your app across every surface and every environment. Before your users do.

live · run 0482staging
$ canary attack
ui/checkout double-submit race held
api/refund amount = −$50.00 broke
mcp/orders malformed tool call held
cli/import 2GB csv, mid-stream kill probing
api/auth expired token replay probing
$
0+
attacks run
0+
breaks caught
0+
rated P0 / P1
01 / How it works

Release the flock.

One loop. Every pull request.

01

Canary reads the diff and your codebase, then works out which flows it can break, before a human review even starts.

$ canary recon --pr 3122
▸ diff: checkout.ts · payments/api.ts
▸ blast radius: checkout · receipts · webhooks
▸ 46 attacks queued
$
02 / The case file

Every failure arrives with proof.

Four breaks a diff review waves right through.

attack replay · api/documentsREPLAY
$ canary attack --surface api/documents
auth as Org A · request a review image by storageId
swap storageId → a document owned by Org B
server resolves it · Org B's private file returned to Org A
· cross-tenant data exposure
$
Case file · api/documentsP0
staging · found autonomously in 6m 09s
Attack
swap storageId to another org's document
Break
one org's private files served to another
Root cause
image-URL resolver looks up by storageId with no org-ownership check
+
Suggested fix
resolveImage(storageId)
+ resolveImage(storageId, { orgId: caller.orgId })
Regression armed
cross-org.storageId reruns on every PR

See what it catches on your code.

Get access →
03 / The adversarial gate

'Done' is a guess.Until it holds.

Canary is the adversarial quality gate for coding agents.

Reviewers read the diff. Canary runs the code, simulates real users, and reports only what actually broke.

Every surface · every environmentWhat a run hunts across your stack
Surface
dev
staging
production
UI flows & states
held
held
held
UX journeys
held
held
held
Backend jobs & data
held
held
held
API REST & GraphQL
held
held
held
MCP tool calls
attacking
broke
held
CLI commands
attacking
held
attacking
Web cross-browser
held
held
attacking
held broke under attackIllustrative · not a live feed

Code, attack, fix.You only ship what survives.

04 / Context

Works where you work.

Canary reads the context you already have, and files every break back to your coding agent.

GitHub
Linear
Sentry
Datadog
Notion
Slack
CANARYattacks
Claude Code
PR · CLI · MCP
05 / Research

Field notes from the frontier.

We publish what we learn measuring AI against real, messy codebases.

Benchmark15 min read · March 2026

QA-Bench v0: measuring how AI models handle code verification

Given a real pull request on a production codebase, can a model find every affected user flow and catch what breaks? We put a purpose-built agent against the frontier models across 35 PRs on four production-scale repos.

Read the benchmark →
Overall accuracy · QA-Bench v0
Canary
83.1
GPT-5.4
80.2
Claude Code
78
Sonnet 4.6
73.2
06 / Get access

Break it before they do.

Put the flock on your next pull request. It runs on every one after.

Get access →Under 10 minutes to set up