Introducing Assert#

Assert is API monitoring for developers who need more than an uptime check.

The Problem with Traditional Monitoring#

Most API monitoring tools check for a 200 status code and stop there.

A 200 does not mean the response is correct. Your API can return 200 with:

• An empty array when it should have data
• A malformed JSON response
• Missing required fields
• Stale cached data
• Incorrect values

Traditional monitors miss all of this. You find out when your users complain.

Response Validation#

Assert checks the values in the response body:

{
  "assertions": [
    { "path": "$.status", "equals": "active" },
    { "path": "$.users", "exists": true },
    { "path": "$.users[0].email", "matches": "/@/" },
    { "responseTime": { "lt": 500 } }
  ]
}

You find out the moment:

• A required field is missing
• A value does not match the expected format
• Response times exceed your thresholds
• Any part of your API contract is broken

The alert names the assertion that failed, what it expected, and what it received.

Multi-Region Monitoring#

APIs behave differently depending on where you call them from. A CDN misconfiguration, a regional database issue, or a routing problem can break your API for users in one region while everyone else sees nothing wrong.

Assert runs every check from 6 regions:

• US East (Virginia)
• US West (Oregon)
• EU West (Ireland)
• EU Central (Frankfurt)
• AP South (Mumbai)
• AP East (Singapore)

When a check fails, Assert re-runs it across the regions and alerts only once they agree. The alert names the regions that agreed, and one flaky node does not wake you.

Get Started#

1. Sign up for free (no credit card required)
2. Add your first endpoint
3. Configure your assertions
4. Choose your regions and check frequency

That takes about five minutes.

What's Next#

Coming soon:

• GraphQL query validation
• OpenAPI spec import
• Custom status pages
• Webhook integrations

Start monitoring your APIs. The free plan sends email alerts.