Introduction

Synthetic Exporter is a synthetic monitoring exporter written in Go.

It checks API HTTP status codes, TLS certificate expiration dates, and runs multi-step headless browser UI scenarios using Playwright for Go. It exports these data points as Prometheus metrics.

Why Synthetic Exporter?

Basic uptime monitoring pings an endpoint to check if the server responds. But modern apps fail in complex ways. A server might return HTTP 200, while a frontend bug stops users from logging in or adding items to a cart.

Synthetic monitoring runs real user interactions (like clicking buttons and filling out forms) in a real browser. This helps you verify that the main flows of your application work end-to-end.

Key Features

• YAML Configuration: Write your UI scenarios with simple actions (goto, fill, click, wait_for_selector, screenshot) without writing Go code.
• Custom Error Labels: Map step failures to specific error_type_name labels (like login_failed or cart_button_missing). This helps you group alerts and find problems faster.
• Secret Management: Use environment variables directly in your config (like ${ENV_VAR}). This keeps your passwords and tokens out of version control.
• Playwright for Go: Uses headless browser automation to test the UI and measure step duration.
• Prometheus Metrics: Exports HTTP status codes, SSL certificate expiration dates, step duration, and error counts. Metrics are labeled by service to help you separate different applications.
• Background Worker: Checks run in a background goroutine on a set schedule. When Prometheus scrapes /metrics, it gets cached data. This prevents scrape timeouts.
• Docker Support: Includes a multi-stage Dockerfile based on the official Playwright image. It uses dumb-init to clean up old Chromium processes and runs as a non-root user.

Next, see how to build and run the exporter in the Getting Started guide.