How to Monitor Multi-Step API Authentication Flows

Source: Dev.to

Overview

Authentication is often the first thing that breaks in an API. A single HTTP check can verify that an endpoint returns 200 OK, but it won’t catch subtle authentication failures such as invalid credentials, expired tokens, or missing cookies. Multi‑step API checks let you chain several HTTP requests so you can validate the entire login flow—from credential submission to token usage.

Setting Up a Multi‑Step Authentication Monitor

1. First step – Log in

Create a POST request to the login endpoint (e.g., /api/auth/login).

POST https://example.com/api/auth/login
Content-Type: application/json

{
  "client_id": "YOUR_CLIENT_ID",
  "client_secret": "YOUR_CLIENT_SECRET"
}

• Expected response: 200 OK with a JSON body that contains an access token.
• Configure Velprove (or your monitoring tool) to extract the token value, e.g.:

{
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6..."
}

Use the extraction syntax {{token}} for later steps.

2. Second step – Use the token

Create a GET request that accesses a protected resource, passing the token from the previous step.

GET https://example.com/api/me
Authorization: Bearer {{token}}

• Expected response: 200 OK with the user’s profile data.

3. Optional third step – Verify another endpoint

You can add additional checks, such as a dashboard endpoint:

GET https://example.com/api/dashboard
Authorization: Bearer {{token}}

• Expected response: 200 OK.

4. Extending the flow

• Token refresh – After the initial login, add a step that calls the token‑refresh endpoint, extracts a new token, and uses it in subsequent requests.
• Session‑based APIs – If the API uses cookies instead of bearer tokens (e.g., WordPress login, WHMCS portals), capture the Set‑Cookie header in the first step and include it in later requests.

Best Practices for Alerting

• Shorter check intervals – On Pro‑tier plans you can run checks every 30 seconds, allowing you to detect authentication failures within a minute instead of waiting several minutes.
• Targeted alert channels – Route alerts to Slack, Discord, Microsoft Teams, webhooks, or PagerDuty (in addition to email) so the right team is notified instantly.
• Dedicated test credentials – Use a separate, non‑production account for monitoring. This avoids rate‑limit hits or lockouts that could affect real users.
• Monitor each auth provider separately – If your app supports multiple login methods (email/password, Google OAuth, SAML, etc.), create a distinct multi‑step check for each. A failure in one provider doesn’t necessarily mean the others are down.

Get Started

If you’re already using simple HTTP checks for health endpoints, upgrading to multi‑step API checks is the natural next step. They verify not only that each endpoint responds, but also that the entire authentication flow works end‑to‑end.

1. Create a Velprove account (free plan available).
2. Add a multi‑step API check – up to 3 steps on the Free tier, 5 on Starter, and 10 on Pro.
3. Scale as needed – upgrade for more steps, faster intervals, or advanced alert integrations.