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Luke · Software Developer
Luke · Software Developer

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Uptime Monitoring Won't Save You: A Guide to API-Based Auth Flow Monitoring

#sass #monitoring #webdev #devops

The 3 AM Wake-Up Call

Your phone buzzes. Then again. And again.

"Can't log in to your app. Just spins forever."

You check your uptime dashboard: 100% green. Server responding perfectly.

But your auth API timed out. Or your token validation broke. Or your Redis session store went down.

Your users are locked out - and your "uptime monitoring" didn't catch it.

Why Uptime Monitoring Misses Auth Failures

Traditional uptime monitoring checks one thing: does the server respond to HTTP requests?

Your authentication involves multiple steps:

User submits credentials
↓
Auth endpoint receives request
↓
Credentials validated (database/auth provider)
↓
Token/session generated
↓
Token returned to client
↓
Subsequent requests authenticated

If ANY step fails, users can't log in. But your homepage still returns 200 OK.

Common auth failures invisible to uptime monitoring:

  • Auth API timeout (server up, endpoint slow)
  • Database connection pool exhausted
  • Auth provider outage (Auth0, Firebase, Okta)
  • Token generation failure
  • Rate limiting triggered
  • Session store unavailable (Redis down)

What Breaks SaaS Authentication

Your Auth Provider

Using Auth0, Okta, Firebase Auth? Their outage = your outage. You've outsourced auth, which means you've outsourced a critical failure point.

Your Auth API

Even with custom auth:

  • Database connection issues
  • Memory/CPU exhaustion
  • Deployment bugs
  • Rate limiting triggered

Token/Session Infrastructure

JWT signing failures. Redis down. Token validation errors. These cause mysterious auth failures.

Third-Party OAuth

Google, Microsoft, GitHub OAuth - if their token endpoint is slow or down, your "Login with Google" breaks.

API-Based Auth Flow Monitoring

The solution: monitor the actual auth flow at the API level.

Example: Login → Authenticated Request Flow

Step 1: POST /api/auth/login

Body: { email: 'test@example.com', password: 'test-password' }
Validate: Status = 200
Extract: $.token as 'auth_token'

Step 2: GET /api/user/profile

Headers: Authorization: Bearer {{auth_token}}
Validate: Status = 200
Validate: Response contains user data

Step 3: POST /api/auth/logout (cleanup)

Headers: Authorization: Bearer {{auth_token}}
Validate: Status = 200

What this catches:

  • Auth endpoint failures
  • Token generation issues
  • Token validation failures
  • Database/backend issues
  • Rate limiting on auth endpoints

Setting Up Auth Flow Monitoring

Step 1: Create Test Account

Create a dedicated monitoring user:

  • test-monitor@yourdomain.com
  • Strong, unique password
  • Minimal permissions (read-only if possible)
  • Excluded from analytics/billing

Important: Don't use real user credentials. Don't use admin credentials.

Step 2: Document Your Auth Flow

Before configuring monitoring:

POST /api/auth/login
Body: { "email": "...", "password": "..." }
Response: { "token": "eyJ...", "user": { "id": "123" } }
Authenticated requests:
Header: Authorization: Bearer <token>

Step 3: Configure Multi-Step API Monitor

Most monitoring tools support this:

  1. Create "Process Flow" or "Multi-step API" monitor
  2. Add login step with credential extraction
  3. Add authenticated request step
  4. Set assertions for each step

Step 4: Alert Configuration

For auth issues, speed matters:

  • Minute 0-5: Email + Slack
  • Minute 5-15: SMS if unacknowledged
  • Minute 15+: Page the team

Auth affects 100% of users. Alert aggressively.

Common Gotchas

Test Account Rate Limiting

Your test account logging in every 5 minutes = 288 logins/day.

Solutions:

  • Whitelist test account from rate limiting
  • Whitelist monitoring IPs
  • Set test account password to never expire

False Positives

Auth monitoring can have more false positives. Use:

  • Retry once before alerting
  • Check from multiple locations
  • Validate specific response content

Emergency Playbook

Minute 0-3: Verify

  1. Try logging in manually (incognito browser)
  2. Check auth provider status page
  3. Check recent deployments

Minute 3-5: Communicate

Before fixing, communicate:

  • Post to your status page
  • "We're aware some users cannot log in. Investigating."

Minute 5-15: Diagnose

Check in order:

  1. Auth provider status
  2. Your auth API logs
  3. Database connectivity
  4. Recent deployments
  5. Rate limiting/WAF logs

After Resolution

  1. Update status page
  2. Email affected users
  3. Post-mortem: how to detect faster?

The Bottom Line

Your authentication is the gate to everything. When it's broken, nothing else matters.

Traditional uptime monitoring won't catch auth issues. You need to:

  • Monitor the actual auth flow
  • Test with real credentials
  • Verify authenticated requests work
  • Alert fast and communicate faster

Set this up today. Your 3 AM self will thank you.

What's your auth monitoring setup? Have you been bitten by "uptime fine, login broken"? Let me know in the comments.

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