Assert String Absent from HTML
Ensure specific text does NOT appear in the rendered page.
The Problem
Catch leaked test data, debug strings, competitor names in your templates, or internal comments that shouldn’t be in production HTML. This assertion fails if the specified string is found anywhere in the page.
The Hard Way
Search the rendered HTML for the forbidden string. Simple per page, but across a pSEO fleet you need automation.
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": "not_contains_string", "value": "TODO"}]}| Parameter | Type | Example |
|---|---|---|
value | string | TODO |
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
contains_string
Verify that specific text appears in the rendered page.
no_placeholders
Find template variables like {{city}} or [TBD] that leaked into production HTML.
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.