Live
Service status
Check live service health and documented failure responses before you integrate.
Web Data
JavaScript SEO rendering check API
Find out what crawlers that skip JavaScript miss. One request fetches the page as raw HTML and as a rendered page, compares the SEO signals of both and lists every difference with its impact.
Category
Web Data
Endpoints
1
Key Features
4
Frequently asked questions
4
Used by people at these companies
Trust signals before you integrate
Transparent docs, authenticated requests, and visible reliability details make it easier to evaluate DomScan before you ship.
OpenAPI
API artifacts
OpenAPI, Swagger, Postman, CLI, SDK, and MCP links are one click away.
API keys
Protected access
Authenticated endpoints use API keys with clear credit costs before you call them.
10,000
Free allowance
Start with 10,000 monthly credits and upgrade only when usage grows.
What this API helps you ship
Use this page as a production brief: endpoints, examples, response shape, and the workflow pieces needed to plug DomScan into your own product.
Embed domain checks, DNS intelligence, risk signals, or enrichment into onboarding, search, and internal tools.
Replace repeated manual lookups with scheduled jobs, alerting, and reproducible investigation steps.
Use predictable fields, documented status codes, and credit costs instead of scraping provider pages.
Feed agents, dashboards, SOAR playbooks, and CRMs through OpenAPI, SDK, Postman, or MCP.
Integration workflow
A simple path from first request to repeatable production usage.
Authenticate once
Send your API key with the documented header and keep requests consistent across services.
Query with examples
Start from the curl and HTTP samples, then map the parameters into your application code.
Operate and monitor
Use status codes, credit costs, and response fields to build retries, logs, and alerts.
Developer kit
Jump from this page into machine-readable docs, request collections, SDKs, or agent tooling.
OpenAPI schema
Generate clients or inspect every request and response shape.
Postman collectionImport ready-made requests for manual testing and team handoff.
SDKs and CLIUse maintained packages and command-line workflows instead of writing boilerplate.
MCP integrationExpose domain intelligence to AI agents and internal assistant workflows.
Parameters and response map
Scan the inputs, output fields, and status codes before wiring the endpoint into your client.
Parameter
url
Example response
statusjs_dependencerendered_word_sharedifferencesissues
HTTP status codes
200400401402429
Endpoints
GET
/v1/onpage/render-diff
Trust signals before you integrate
Transparent docs, authenticated requests, and visible reliability details make it easier to evaluate DomScan before you ship.
Service status
API artifacts
OpenAPI, Swagger, Postman, CLI, SDK, and MCP links are one click away.
API keys
Protected access
Authenticated endpoints use API keys with clear credit costs before you call them.
Free allowance
Sign up for free
Start with 10,000 monthly credits and upgrade only when usage grows.
Active
Example request
Start from the curl and HTTP samples, then map the parameters into your application code.
Key Features
Side by side signals
Title, meta description, canonical, robots, H1, word count, internal and external links, structured data, hreflang and language, extracted the same way from both versions.
Impact for every difference
Each difference is labelled added, removed or changed by JavaScript, with a high, medium or low impact, so you can fix the ones that matter first.
One dependence level
A single none, low, medium or high JavaScript dependence level and the share of words that only exist after rendering make pages easy to compare.
Risky changes flagged
Robots directives or canonicals rewritten by scripts, titles and H1s that need JavaScript and content or links that only appear after rendering are listed as issues.
Example request
curl -H "X-API-Key: $DOMSCAN_API_KEY" "https://domscan.net/v1/onpage/render-diff?url=example.com/shoes/trail-runner"Example response
{
"status": "ok",
"js_dependence": "high",
"rendered_word_share": 1,
"differences": [
{ "field": "robots", "change": "changed_by_js", "impact": "high", "raw": "noindex", "rendered": "index, follow" },
{ "field": "h1", "change": "added_by_js", "impact": "high", "raw": [], "rendered": ["Trail Running Shoes"] },
{ "field": "word_count", "change": "added_by_js", "impact": "high", "raw": 0, "rendered": 122 }
],
"issues": ["robots_changed_by_js", "h1_requires_js", "content_requires_js"]
}Frequently asked questions
Why does this matter for SEO and AI search?
Search engines may render JavaScript later or with limits, and many AI crawlers read only the raw HTML. Anything that exists only after rendering can be missed or indexed late.
What counts as a difference for word and link counts?
Counts must change by at least 20 percent, and word counts by at least 25 words, so small dynamic widgets do not create noise.
What happens if one of the two fetches fails?
The comparison needs both versions. If either one cannot be read, the result is unknown with a reason and the request is refunded.
How many credits does it cost?
Seven credits per check, because every request reads the page twice, once raw and once rendered.
Related tools and resources
HTTP status codes
These are the HTTP status codes to handle, so you can tell apart successful responses, auth issues, credits, rate limits, missing data, and upstream failures.
OK
200
Request successful
Bad Request
400
Invalid parameters
Unauthorized
401
Missing or invalid API key/session.
Payment Required
402
Not enough credits to run this request.
Too Many Requests
429
Rate limit exceeded
Check JavaScript SEO