Assert Regex Pattern Match
Verify that a regex pattern matches somewhere in the page HTML.
The Problem
When you need more than a simple substring — phone number formats, price patterns, structured IDs — a regex assertion lets you validate that the rendered HTML matches a specific pattern. Useful for catching malformed dynamic data in pSEO templates.
The Hard Way
Write a script that fetches each URL, compiles the regex, and tests it against the HTML. Handle compilation errors, timeouts, and reporting across thousands of pages.
The SEODiff Way
One API call. Results in under 2 seconds.
POST https://seodiff.io/api/v1/agent/evaluate
{"urls": ["https://example.com/product/widget-a"], "assertions": [{"rule": "regex_match", "value": "\\$\\d+\\.\\d{2}"}]}| Parameter | Type | Example |
|---|---|---|
value | regex | \\$\\d+\\.\\d{2} |
Code Examples
Copy-paste examples in your preferred language:
cURL
See the full evaluation example in cURL →
Python
See the full evaluation example in Python →
Node.js
See the full evaluation example in Node.js →
Go
See the full evaluation example in Go →
PHP
See the full evaluation example in PHP →
Related Assertions
regex_not_match
Ensure a regex pattern does NOT match in the page HTML.
contains_string
Verify that specific text appears in the rendered page.
Use in CI/CD
Add this assertion to your deployment pipeline. Works with any CI platform:
🐙 GitHub Actions
Block bad deployments with automated SEO checks in your GitHub Actions CI/CD pipeline.
🦊 GitLab CI
Add automated SEO quality gates to your GitLab CI/CD pipelines.
▲ Vercel
Automatically validate SEO on every Vercel preview deployment before promoting to production.