Modern deployment platforms generate preview URLs for every pull request. Vercel deploys a preview for every branch. Netlify generates deploy previews automatically. Railway, Render, and Fly.io offer similar functionality.

These preview deployments are the perfect testing target. The code is deployed. The application is running. All you need is something to test it before the PR merges.

This tutorial walks through connecting an AI testing agent to your deployment platform so every preview deployment gets comprehensive automated testing.

The Architecture

The workflow is straightforward:

1. Developer pushes code to a branch

2. Deployment platform builds and deploys a preview

3. GitHub receives the deployment status

4. TestSprite detects the deployment and runs a comprehensive test suite against the preview URL

5. Test results post on the PR

6. Developer reviews results and merges (or fixes and pushes again)

This architecture works with any deployment platform that generates preview URLs and reports deployment status to GitHub.

Setup by Platform

Vercel

Vercel automatically creates preview deployments for every PR and reports status to GitHub. TestSprite's GitHub App detects the deployment and uses the preview URL as the test target.

Steps:

1. Install the TestSprite GitHub App on your repository

2. Configure TestSprite to use the Vercel preview URL pattern

3. Push a branch and open a PR

4. Vercel deploys the preview. TestSprite runs tests against it. Results appear on the PR.

No additional configuration needed. Vercel's GitHub integration and TestSprite's GitHub integration work together natively.

Netlify

Netlify's deploy previews work similarly. Each PR gets a unique preview URL. TestSprite detects the deployment and runs tests automatically.

Steps:

1. Ensure Netlify's GitHub integration is enabled (deploy previews on)

2. Install the TestSprite GitHub App

3. Configure TestSprite with your Netlify preview URL pattern

4. Every PR triggers a Netlify preview build followed by TestSprite testing

Railway / Render / Fly.io

These platforms offer preview environments through different mechanisms. Railway has PR environments. Render has preview services. Fly.io has review apps.

Steps:

1. Enable preview/PR environments on your deployment platform

2. Install the TestSprite GitHub App

3. Configure TestSprite with the preview URL pattern for your platform

4. PRs trigger preview deployments, which trigger TestSprite testing

What Gets Tested

Once connected, TestSprite runs the following on every preview deployment:

• UI flow testing: Complete user journeys from signup to core features

• API functional testing: Every endpoint tested with valid and invalid inputs

• Security testing: IDOR, authentication bypass, input sanitization, XSS

• Error handling: What happens when things go wrong — network errors, invalid data, expired sessions

• Authentication flows: Login, signup, password reset, session management

• Cross-browser compatibility: Tests run against the deployed preview across browsers

All of this completes in under five minutes. The PR gets a comprehensive quality report before anyone reviews the code.

The Result

With this setup, your deployment pipeline gains a testing layer that requires zero ongoing effort:

• No test scripts to write or maintain

• No CI/CD pipeline to configure (beyond the initial GitHub App installation)

• No test runner to manage

• No test data to set up

Every PR gets the same comprehensive verification regardless of which deployment platform you use. The testing agent adapts to whatever URL it receives.

TestSprite's free tier supports all major deployment platforms. Setup takes minutes.

Try TestSprite free →