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Assert on the response, not just the status.

A method, URL, interval, and assertions go in. Pass or fail, with status, latency, and evidence, comes out.

Start building Read the docs
Checking every 60s
test
GETapi.example.com/health
Healthy
last 16 checks · interval 60slatest 184 ms
12 consecutive passing checks. Flowyn requests the URL, records status and latency, and does not touch your API.
What it does

Real product states, not a promise.

A method, URL, interval, and assertions go in. Pass or fail, with status, latency, and evidence, comes out.

  • Status code and header assertions
  • JSON body and text body assertions
  • Response time assertions
  • Incidents like HTTP checks
Input

Method, URL, interval, and assertions

Output

Pass or fail, with status, latency, and evidence

Where it fits

Where it fits

01

Contract checks on APIs

02

Post-deploy verification

03

Partner API monitoring

API example

One durable request.

POST /v1/monitors. Use an idempotency key on create calls. The full request and response contract is in Flowyn Docs.

POSThttps://api.flowyn.dev/v1/monitors201
curl -X POST https://api.flowyn.dev/v1/monitors \
  -H "Authorization: Bearer flw_test_••••" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: check-orders-api" \
  -d '{
    "name": "Orders API",
    "type": "api_check",
    "method": "GET",
    "url": "https://api.example.com/health",
    "interval_seconds": 300,
    "timeout_ms": 5000,
    "assertions": [
      {
        "source": "status_code",
        "operator": "equals",
        "expected": 200
      },
      {
        "source": "json_body",
        "property": "$.status",
        "operator": "equals",
        "expected": "ok"
      }
    ]
  }'
POST /v1/monitorsHTTP checksPOST /v1/monitorsHeartbeatsGET /v1/issues/{fingerprint}Issues & diagnostics

Frequently asked questions

Where is the exact request contract for API checks?
In Flowyn Docs and the OpenAPI document at https://api.flowyn.dev/openapi/v1.yaml. This page shows the request; the docs page lists every field, status value, error, and limit.
Is the operation durable?
Yes. The operation is stored before any work happens and remains a resource with state, attempts, and error context, not an ephemeral request log.
Do failures stay inspectable?
Yes. Every attempt is recorded. Repeated failures with the same fingerprint are also grouped into an Issue.

Build with API checks.

Create a workspace, make your first call in the test environment, and inspect every attempt.

Start building Read the docs