Secrets are masked before they are stored
Authorization headers, cookies and fields you name are replaced with bullets at capture, so a replay link never contains a live token. Platform adds SSO and an audit log of who changed which check.
/Features
Six things Assert does, and the things it doesn't.
Assert calls your API on a schedule, compares what comes back with what you promised, and tells one named person when the two disagree. That is the whole product. Below is each part, what it looks like in use, and where it stops.
01/
Six probes, one verdict.
Every check runs from six probes at the same moment. One slow probe usually points at a routing problem between that probe and you. Six slow probes point at your database. You get told which one you have, instead of guessing from a single graph.
Intervals go down to 15 seconds on Platform, one minute on Team, five on Side Project.
In your weekSet a latency budget once per endpoint. Assert only pages anyone when the budget is blown from more than one probe.
02/
Drift, diffed against your own spec.
Assert compares every live response with your OpenAPI file. A field that turns null, an enum value nobody documented, a 200 that became a 201: each shows up with the exact path and the last clean response.
The catch: it believes your spec. If the spec is wrong, Assert will agree with it. So the diff has two buttons, “Mark intended” and “Update spec”, and you choose.
In your weekDrift lands as a warning, not a page. Someone reads it in the morning and decides whether the code or the spec moves.
03/
Replay the exact call that failed.
Every failed check keeps the full request, response and a timing waterfall. Authorization headers and tokens are masked before storage. Open the link in the alert and you are looking at the call, ready to fire again or copy as cURL.
In your week“Can anyone reproduce this?” stops being a thread. The answer is a button, and it shows the 502 again.
04/
Alerts that find their owner.
Route by path, by owner or by hour, to Slack, PagerDuty or a webhook. Payments breakage goes to the payments channel. A staging blip at 3 a.m. goes nowhere. If nobody acknowledges in five minutes, the rule escalates.
In your weekThe first message already carries the status, latency, owner and replay button. Nobody opens a dashboard to find out what happened.
05/
A gate in your CI.
Add one line to your pipeline and the same contract tests run against the build before it ships. A change that removes a field the spec promises fails the build. The deploy never goes out.
Available on Team and Platform. It moves the argument into the pull request, where it is cheap.
In your weekA rename like phone to phone_number gets blocked on staging on a Sunday afternoon instead of breaking mobile clients on Monday.
06/
GraphQL, checked by operation.
A GraphQL endpoint has one URL and a thousand shapes, so a URL check tells you almost nothing. Assert runs named operations, like CartQuery, and checks the response shape and the errors array, not just the 200.
In your weekFind any check from the keyboard with ⌘K, silence it, replay it or assign it without leaving the list.
/The honest part
What Assert won't do.
- Watch your frontendIt calls the API. If you need to see what browsers see, run a real-user tool next to it.
- Write your testsIt drafts one check per path from your spec. You decide what “broken” means.
- Fix the bugIt tells you first, with the request attached. The fixing is yours.
- Correct a wrong specDrift is measured against your file. A stale spec produces confident, useless diffs.
/Security, integrations, reliability
The boring parts, in writing.
The things a security reviewer and an on-call engineer both ask before they agree to add a tool.
Probes in six places, checked against each other
A single probe failing alone is treated as a probe problem, not yours. Your alert fires when the failure holds across probes. Platform can add private network probes for internal APIs.
Where the alert lands
Slack and Microsoft Teams for people, PagerDuty for the pager, Datadog for metrics, webhooks for the rest.
- Slack
- Teams
- PagerDuty
- Datadog
OpenAPI in, checks out
Paste a URL to your OpenAPI file. Assert drafts a check per path and runs none until you approve them.
Keeps what you paid for
7 days of history on Side Project, 90 on Team, longer with reporting on Platform. Then it is deleted.
Know first. Fix it before anyone files a ticket.
Pick a plan, point Assert at your OpenAPI spec, and your endpoints are being watched before the next deploy. Plans start at $219 a year, billed annually.