AI test engineer for API teams

API tests that
keep up with your code.

Stresseur learns your real API flows while you develop, creates the functional, regression, E2E and stress tests every change needs, and proposes updates on every PR.

Start testing freeSee how it works ↓

Dev-only SDK · runs locally · review every generated test

stresseur

● Learning — watching localhost:3000

18 endpoints discovered

4 user flows mapped

3 authentication contexts identified

● PR #1284 — added POST /v2/orders

checkout flow affected · 3 dependent steps

● Action taken

✓ 6 tests generated · +4 edge cases

✓ 2 flows updated — suggestion ready

⚠ 1 breaking change found

❯ run affected tests❯ review changes❯ stress this flow

Runs where your team already works

GitHub Actions·Claude Code·Cursor·MCP·Fly.io·Any CI

The mechanism

Use your app.
Stresseur learns how it works.

Add the dev-only SDK to localhost and keep developing normally. Stresseur observes API activity, connects dependent requests, and identifies real user flows — a living map of how your application actually behaves. Repository and OpenAPI analysis discover the rest.

observed flow mapcheckout.flow.yaml
Login→Create cart→Add item→Checkout→Payment

chained vars cartId → orderId → paymentIntent

auth context session cookie (auto-refreshed)

coverage ✓ 4 of 5 steps asserted · Payment missing edge cases

…and 3 more observed flows

One flow

One learned flow.
Every kind of test.

Stresseur learns the flow once — then tests it every way your change deserves.

Functional

Does each API behave correctly?

Regression

Did this change break existing behavior?

E2E

Does the whole multi-service journey work?

Edge cases

What inputs and states did we overlook?

Stress

How does the same flow behave at 10,000 users?

PR intelligence

A test engineer inside
every pull request.

Every change gets the tests it needs. Stresseur reads the diff, maps it onto the flows it learned, and acts — before you merge.

PR changeStresseur action
New endpointGenerates initial coverage
Changed schemaUpdates affected flows for review
Removed routeFinds broken dependencies
Changed business logicRuns impacted regression tests
Performance-sensitive changeCompares against its baseline
scsarah-chencommented 2 hours ago
@stresseur test
stresseurbotcommented 1 hour ago
Test suite · checkout✓ 20 passed✗ 1 failed

21 tests · 2.4s · runs on every PR

✗ Create order › returns 201
POST /v1/orders → 404
diagnosis route moved to /v2/orders in this PR (#1,284)
fix 3 steps updated · suggestion pushed below
generated +3 tests for the new /v2/orders schema

Rerun after the suggestion: ✓ 21/21 green

Full report → stresseur.dev/r/run_9x2k · nothing changes without your approval

stresseur suggested a changebot

tests/checkout.flow.yaml

  - name: Create order
    request:
      method: POST
-      url: {{base}}/v1/orders+      url: {{base}}/v2/orders      body:
-        quantity: 1+        qty: 1
detected: /v1/orders → 404 after #1,284Commit suggestion

Maintain

A test suite that maintains itself — with your approval.

Endpoints change. Test suites rot — that’s why they die. Stresseur reads the failure artifacts and your diff, then proposes updated tests as reviewable suggestions on the PR that broke them. Nothing changes without your sign-off.

  • ✓ Every failure ships with the artifacts the agent reasons over
  • ✓ Updates land as reviewable suggestions on the same PR
  • ✓ Assertions and thresholds are yours — Stresseur proposes, you approve

Talk to it

Just tell it what to test.

No harness to learn. No scripts to babysit. Say what matters — Stresseur does the rest.

❯

Stresseur, test this endpoint.

❯

Stresseur, cover the APIs changed in this PR.

❯

Stresseur, run every flow that uses /v2/orders.

❯

Stresseur, find missing edge cases.

❯

Stresseur, stress checkout with 10,000 users.

❯

Stresseur, explain what broke.

from your editor, your terminal, or your PR thread

Trust & control

Your traffic is sensitive.
You stay in control.

Observing real API activity is a responsibility, not a growth hack. Stresseur is built so the data stays yours.

✓

Dev-only package

Ships in your dev dependencies. Never enters production bundles.

✓

Host allowlists

You choose exactly which hosts Stresseur can observe.

✓

Automatic redaction

Secrets, auth headers, and bodies are scrubbed before anything is stored.

✓

Local-first processing

Observed flows stay on your machine until you choose to share them.

✓

Reviewable by default

Every generated test and every update lands as a suggestion you can read.

✓

No silent changes

Assertions and performance thresholds can never change without your approval.

Integrations

From your editor, terminal, CI, or PR.

Stresseur ships an MCP server and a GitHub App, so Claude Code, Cursor, and your CI bots work the same learned flows — before the PR merges.

test_apigenerate_testsrun_suitediagnose_failurestress_flow
claude_desktop_config.json
{
  "mcpServers": {
    "stresseur": {
      "command": "npx",
      "args": ["-y", "stresseur-mcp"]
    }
  }
}

Pricing

Open source at the core.
Cloud when you want it.

DevTools · open source

$0forever

The toolkit that learns and runs your flows.

  • ✓Dev-only recorder SDK
  • ✓YAML flows you own
  • ✓Runner + GitHub Action
  • ✓Local stress mode
  • ✓Apache-2.0
Get the CLI
Early access

Stresseur Cloud

$0during early access

The AI engineer on top of your flows.

  • ✓AI test generation & edge cases
  • ✓PR-aware maintenance, with review
  • ✓Diagnosis with fix proposals
  • ✓Hosted runs, history & baselines
  • ✓Distributed stress testing
Start testing free

Everything in Stresseur Cloud is free during early access. Pricing lands with GA.

Meet your AI
test engineer.

Start free. See your API map in the first five minutes.

Start testing free