Verify H1 Tag Presence

Ensure every page has exactly one H1 heading tag.

The Problem

Every page needs a clear H1 that tells Google and AI crawlers what the page is about. Missing H1s are a common template bug — especially in SPAs where the H1 is rendered client-side and invisible to crawlers.

The Hard Way

View source, Ctrl+F for <h1>. Easy per page, but pSEO templates generate thousands of pages that all need checking after every code change.

The SEODiff Way

One API call. Results in under 2 seconds.

POST https://seodiff.io/api/v1/agent/evaluate

{"urls": ["https://example.com/landing/city-page"], "assertions": [{"rule": "has_h1"}]}

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

`has_meta_description`

Ensure every page has a non-empty meta description tag.

`has_schema`

Ensure every page has valid JSON-LD schema markup for rich results.

`selector_exists`

Verify critical DOM elements are present on every 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.