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Posted on • Originally published at velprove.com

How to Monitor Multi-Step API Authentication Flows

#webdev #devops #monitoring #uptime

Authentication is almost always the first thing to break. Your login
flow touches your web server, your database, your session store or token
issuer, and often one or more third-party identity providers. A failure
in any one of those components means your users cannot log in, even if
every other page on your site loads perfectly.

The challenge is that a single HTTP check cannot test an authentication
flow. Logging in is inherently multi-step: you send credentials, receive
a token, and then use that token to access a protected resource. If you
only check the login endpoint with a GET

Why Single-Request Checks Fall Short

Consider a typical API login flow. A client sends a
POST

/api/auth/login
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Authorization
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A standard HTTP monitor can check that /api/auth/login

200 OK
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Real authentication failures are subtle. The login endpoint responds,
but the token it returns is malformed. Or the session store is full and
new sessions silently fail. Or a key rotation broke JWT verification on
downstream services. These are the failures your users hit, and they are
invisible to single-request monitoring.

Setting Up a Multi-Step API Check

Velprove's Multi-Step API checks let you chain multiple HTTP
requests together, passing data from one step to the next. This is
exactly what you need to test an authentication flow end-to-end.

Multi-Step API checks are available on all plans. The free plan
includes up to 3 steps, Starter gives you 5, and Pro gives you 10.
This is enough to test most authentication flows right away.

Here is how to set up a multi-step authentication monitor:

Step 1: Send login credentials

Create the first step as a POST

200
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Step 2: Extract the token

Configure Velprove to extract the token value from the JSON response of
Step 1. For a typical JWT flow, you extract the value from a field
like access_token

token
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Step 3: Access a protected endpoint

Create a second HTTP request, a GET

/api/me
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/api/dashboard
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Authorization
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Bearer {{token}}
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200 OK
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If any step in the chain fails (the login endpoint returns an error,
the token extraction fails, or the protected endpoint rejects the
token), the entire check fails and you receive an alert.

Adapting for Different Auth Patterns

OAuth 2.0 client credentials

For machine-to-machine authentication, your first step sends a
POST

client_id
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client_secret
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access_token
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JWT with refresh tokens

You can extend your multi-step check to also test token refresh. After
the initial login, add a step that calls your refresh endpoint with the
refresh token. Then use the new access token to hit a protected
endpoint. This catches failures in your token refresh logic before users
get unexpectedly logged out.

Session-based authentication

For traditional session-based APIs that return cookies instead of
tokens, Velprove carries cookies forward between steps automatically.
Your first step logs in, the server sets a session cookie, and
subsequent steps use that cookie to access protected routes, just like
a real browser session. For full browser-based login monitoring of
applications like WordPress or WHMCS, see our guides on 

      monitoring WordPress login

    and 

      monitoring WHMCS portals

    .
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Alerting Strategy for Auth Failures

Authentication failures deserve a different alerting strategy than
general uptime issues. When your homepage is slow, it is annoying. When
your login flow is broken, no one can use your product. Treat auth
monitor failures as critical-severity incidents.

  • Set shorter check intervals. On the Pro plan, you can run checks every 30 seconds. For your primary authentication flow, this means you find out about failures within a minute instead of waiting five minutes.
  • Route alerts to the right channel. Paid plans support Slack, Discord, Teams, webhooks, and PagerDuty alongside email. Connect your auth monitors to PagerDuty so login failures trigger on-call rotations automatically.
  • Use separate test credentials. Create a dedicated test account for monitoring. Do not use a real user account. You do not want monitoring activity to trigger rate limits or security lockouts that affect a real user.
  • Monitor across auth providers. If your application supports multiple login methods (email and password, Google OAuth, SAML), set up a separate multi-step check for each one. A failure in one provider does not always mean the others are down. ## Get Started

If you are already monitoring your 

      API health endpoints

    with simple HTTP checks, multi-step API checks are the natural next
    layer. They validate that your endpoints do not just respond. They
    work together as a complete authentication flow.
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Create your Velprove account and start with
the free plan. Multi-step API checks are included on all plans
(up to 3 steps on Free, 5 on Starter, 10 on Pro). Upgrade when you
need more steps, faster intervals, or advanced alert integrations.

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