Debug auth flows
in real-time
Stop blindly guessing why your Playwright tests fail. Visually trace the exact OTP extraction flow, measure sub-millisecond latencies, and pinpoint failure points live.
Email Received
⚠️ slowOTP Extracted
847291
Identify and track
automated test runs
Use client.inboxes.startTest to group requests into isolated runs. Drop this pattern into your testing suite and watch the debugger light up dynamically as your CI executes.
import { test, expect } from '@playwright/test';
import { FreeCustomEmail } from 'freecustom-email';
const fce = new FreeCustomEmail('fce_test_key');
test('signup flow works', async ({ page }) => {
// The debugger tracks this specific inbox
const { inbox } = await fce.inboxes.register('test', true);
await fce.inboxes.startTest(inbox, 'e2e-signup');
await page.goto('https://myapp.com/signup');
await page.fill('#email', inbox);
await page.click('#submit');
const { otp, score } = await fce.otp.waitFor(inbox);
console.log(`OTP Confidence: ${score * 100}%`);
await page.fill('#otp', otp);
});
Three steps to tracing
01
Identify test runs
Use the SDK's startTest method or POST to /tests to group events under a single test run ID.
02
Watch events stream
Experience real-time visualization of the email → parsing → OTP extraction flow.
03
Debug failures
Tap any event to inspect raw SMTP payloads and pinpoint exact execution latencies.
Surgical precision for your E2E test suites
01
Real-time event streaming
Watch your test runs unfold second-by-second. No refresh required.
02
Sub-ms latency tracking
Know exactly how long each step takes — from trigger to OTP extraction.
03
Failure insights
Automated detection of timing issues, delivery failures, and regressions.
04
Timeline history
Replay past test runs to visually understand exactly what went wrong.
Unlock full tracing history
The Auth Flow Debugger is deeply integrated into the core platform. Paid plans unlock longer historical retention and live WebSocket streaming features.
Included
Startup Tier
Basic tracing
Full Debugger enabled
24-hour timeline history
NO live websocket
Included
Growth Tier
Full debugger
Live WebSocket streaming
Failure Insights
7 days (168h) history
Included
Enterprise Tier
Scale & security
Dedicated streaming clusters
Priority Infra & SLA enabled
30 days (720h) history
Frequently asked questions
What is the Auth Flow Debugger?+
It is a visual interface that streams real-time events for your automated tests. It traces exactly when an email is received, when the OTP is extracted, and measures sub-millisecond latencies between steps.
How do I group my requests into a 'Test Run'?+
Simply call `client.inboxes.startTest(email, 'my-test-id')` or make a POST request to `/v1/inboxes/{inbox}/tests`. All subsequent emails delivered to that inbox will be grouped under the same visual timeline.
Does the debugger work with Playwright and Cypress?+
Yes. Since it operates entirely on the API side, it works seamlessly with Playwright, Cypress, Selenium, or any custom Node/Python automation script.
Can I view historical test runs?+
Yes. Paid plans (Startup and above) retain historical timelines so you can retroactively inspect failed CI/CD pipelines hours or days after they occurred.