> For the complete documentation index see https://domscan.net/llms.txt. Markdown versions of every docs page are available by appending .md to the page URL. Source: https://domscan.net/docs/products/javascript-seo # JavaScript SEO rendering check API API Compare raw and rendered HTML to see which SEO signals depend on JavaScript. Use this reference to choose an operation and integrate its documented response contract. [View product page](https://domscan.net/javascript-seo-api) ## Operations GET `/v1/onpage/render-diff` [View API reference](https://domscan.net/docs/products/javascript-seo#getRenderDiff) ## GET `/v1/onpage/render-diff` Operation: `getRenderDiff` Credits and authentication: 7 Authentication required GET /v1/onpage/render-diff Credits: 7 #### Query parameters | Parameter | Type | required | | --- | --- | --- | | url | string | required | #### Response fields | Field | Type | | --- | --- | | `url` | string | | `final_url` | string | | `status` | string | | `reason` | string \| null | | `checked_at` | string | | `raw` | object | | `raw.fetch` | object | | `raw.fetch.http_status` | integer \| null | | `raw.fetch.final_url` | string | | `raw.fetch.content_type` | string \| null | | `raw.fetch.bytes` | integer | | `raw.fetch.truncated` | boolean | | `raw.fetch.redirect_count` | integer | | `raw.fetch.duration_ms` | integer | | `raw.fetch.rendered` | boolean | | `raw.signals` | object | | `raw.signals.title` | string \| null | | `raw.signals.meta_description` | string \| null | | `raw.signals.canonical` | string \| null | | `raw.signals.robots` | string \| null | | `raw.signals.noindex` | boolean | | `raw.signals.h1[]` | string[] | | `raw.signals.word_count` | integer | | `raw.signals.internal_links` | integer | | `raw.signals.external_links` | integer | | `raw.signals.structured_data_types[]` | string[] | | `raw.signals.hreflang_count` | integer | | `raw.signals.lang` | string \| null | | `rendered` | object | | `rendered.fetch` | object | | `rendered.fetch.http_status` | integer \| null | | `rendered.fetch.final_url` | string | | `rendered.fetch.content_type` | string \| null | | `rendered.fetch.bytes` | integer | | `rendered.fetch.truncated` | boolean | | `rendered.fetch.redirect_count` | integer | | `rendered.fetch.duration_ms` | integer | | `rendered.fetch.rendered` | boolean | | `rendered.signals` | object | | `rendered.signals.title` | string \| null | | `rendered.signals.meta_description` | string \| null | | `rendered.signals.canonical` | string \| null | | `rendered.signals.robots` | string \| null | | `rendered.signals.noindex` | boolean | | `rendered.signals.h1[]` | string[] | | `rendered.signals.word_count` | integer | | `rendered.signals.internal_links` | integer | | `rendered.signals.external_links` | integer | | `rendered.signals.structured_data_types[]` | string[] | | `rendered.signals.hreflang_count` | integer | | `rendered.signals.lang` | string \| null | | `js_dependence` | string \| null | | `rendered_word_share` | number \| null | | `differences[]` | object[] | | `differences[]` | object | | `differences[].field` | string | | `differences[].change` | string | | `differences[].impact` | string | | `differences[].raw` | unknown | | `differences[].rendered` | unknown | | `issues[]` | string[] | #### Example request ```bash curl -H "X-API-Key: $DOMSCAN_API_KEY" "https://domscan.net/v1/onpage/render-diff?url=https%3A%2F%2Fexample.com" ``` ```javascript const response = await fetch("https://domscan.net/v1/onpage/render-diff?url=https%3A%2F%2Fexample.com", { headers: { "X-API-Key": process.env.DOMSCAN_API_KEY }, }); const data = await response.json(); console.log(data); ``` ```python import os import requests response = requests.get( "https://domscan.net/v1/onpage/render-diff?url=https%3A%2F%2Fexample.com", headers={"X-API-Key": os.environ["DOMSCAN_API_KEY"]}, ) print(response.json()) ``` ```go package main import ( "fmt" "io" "net/http" "os" ) func main() { req, err := http.NewRequest(http.MethodGet, "https://domscan.net/v1/onpage/render-diff?url=https%3A%2F%2Fexample.com", nil) if err != nil { panic(err) } req.Header.Set("X-API-Key", os.Getenv("DOMSCAN_API_KEY")) resp, err := http.DefaultClient.Do(req) if err != nil { panic(err) } defer resp.Body.Close() data, err := io.ReadAll(resp.Body) if err != nil { panic(err) } fmt.Println(resp.Status, string(data)) } ``` ```ruby require "json" require "net/http" uri = URI("https://domscan.net/v1/onpage/render-diff?url=https%3A%2F%2Fexample.com") request = Net::HTTP::Get.new(uri) request["X-API-Key"] = ENV.fetch("DOMSCAN_API_KEY") response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http| http.request(request) end puts JSON.pretty_generate(JSON.parse(response.body)) ``` #### Example response ```json { "url": "https://example.com/shoes/trail-runner", "final_url": "https://example.com/shoes/trail-runner", "status": "ok", "reason": null, "checked_at": "2026-10-13T12:00:00.000Z", "raw": { "fetch": { "http_status": 200, "final_url": "https://example.com/shoes/trail-runner", "content_type": "text/html", "bytes": 183, "truncated": false, "redirect_count": 0, "duration_ms": 380, "rendered": false }, "signals": { "title": "Example Outdoor", "meta_description": null, "canonical": null, "robots": "noindex", "noindex": true, "h1": [], "word_count": 0, "internal_links": 0, "external_links": 0, "structured_data_types": [], "hreflang_count": 0, "lang": "en" } }, "rendered": { "fetch": { "http_status": 200, "final_url": "https://example.com/shoes/trail-runner", "content_type": "text/html", "bytes": 3535, "truncated": false, "redirect_count": 0, "duration_ms": 4210, "rendered": true }, "signals": { "title": "Trail Running Shoes for Rocky Terrain | Example Outdoor", "meta_description": "Lightweight trail running shoes with a grippy outsole, rock plate and breathable mesh. Free returns within 30 days on every pair.", "canonical": "https://example.com/shoes/trail-runner", "robots": "index, follow", "noindex": false, "h1": [ "Trail Running Shoes for Rocky Terrain" ], "word_count": 122, "internal_links": 5, "external_links": 2, "structured_data_types": [ "AggregateRating", "Brand", "BreadcrumbList", "ListItem", "Offer", "Product", "Rating", "Review" ], "hreflang_count": 3, "lang": "en" } }, "js_dependence": "high", "rendered_word_share": 1, "differences": [ { "field": "title", "change": "changed_by_js", "impact": "high", "raw": "Example Outdoor", "rendered": "Trail Running Shoes for Rocky Terrain | Example Outdoor" }, { "field": "meta_description", "change": "added_by_js", "impact": "medium", "raw": null, "rendered": "Lightweight trail running shoes with a grippy outsole, rock plate and breathable mesh. Free returns within 30 days on every pair." }, { "field": "canonical", "change": "added_by_js", "impact": "high", "raw": null, "rendered": "https://example.com/shoes/trail-runner" }, { "field": "robots", "change": "changed_by_js", "impact": "high", "raw": "noindex", "rendered": "index, follow" }, { "field": "noindex", "change": "removed_by_js", "impact": "high", "raw": true, "rendered": false } ], "issues": [ "robots_changed_by_js", "canonical_changed_by_js", "h1_requires_js", "content_requires_js", "links_require_js", "structured_data_changed_by_js" ] } ``` #### HTTP status codes - `200` OK - `400` Bad Request - `401` Unauthorized - `402` Payment Required - `429` Too Many Requests ## Reference resources [OpenAPI 3.0](https://domscan.net/v1/openapi.json) [Postman](https://domscan.net/v1/postman.json) [MCP](https://domscan.net/mcp-domain-checker)