JS HTML Renderer API

Free Public API

Execute client-side JavaScript, hydrate SPAs (React, Vue, Angular), and extract the fully rendered DOM.

Try in Live Web Tool

POSThttps://api.headless-lender.com/api/v1/render

Public: No Key Needed•Highest Free Quota: 1,000 Req/Mo + 10h Browsers (No Card Required)

Overview & Architecture

Execute complex client-side Single Page Applications (SPAs) in an isolated cloud Chromium instance. Waits for dynamic network requests, async API hydration, or specific DOM selectors before returning the fully rendered HTML.

Executes client-side React, Vue, Angular, and Svelte bundles

Waits for network idle or custom CSS selector appearance

Extracts full outerHTML or targeted element DOM

Anti-bot stealth mode bypasses typical headless blocks

Playwright Execution & Valkey Caching Pipeline

Because this endpoint utilizes full headless Chromium rendering, dynamic JavaScript and single-page apps (SPAs) are executed completely before conversion:

1. Cold Scrape (Cache MISS)~800ms – 2.5s

Chromium initializes, fetches the URL, executes client JavaScript, resolves DOM mutations, and generates output.

2. Repeat Request (Cache HIT)~5ms – 15ms

Returned instantly from Valkey/Redis cache with header X-Lender-Cache: HIT (15-minute TTL).

Code Integration Examples

Instant Public Endpoint: Zero configuration, no API key needed. Want our highest free quota? Get 1,000 free requests/month + 10 hours of cloud browsers with a free key (No credit card required).

curl -X POST https://api.headless-lender.com/api/v1/render \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://news.ycombinator.com",
    "waitUntil": "networkidle",
    "includeHtml": true
  }'

Headers & Authentication Standard

1. Public Access (No Key)

No Authorization header required. Simply send a JSON POST request. Perfect for quick prototypes, small scripts, and low-volume scraping.

Content-Type: application/json

2. Free API Key (Highest Free Quota)

1,000 Req/Mo Free

Sign up in 10s with no credit card required. Unlocks 1,000 free monthly requests, 600 browser minutes (10 hours), 120 req/min burst limits, and cache-bypass controls.

Authorization: Bearer hl_live_your_api_key_here

Access Mode	Monthly Quota	Cloud Browser Time	Burst Limit	Credit Card	Action
Public Anonymous	Daily IP Allowance	5-min trial sandbox	10 req/min	None	Instant (No Setup)
Free Account (Highest Quota)	1,000 Req / Month	600 Mins (10 Hours)	120 req/min	Zero ($0 forever)	Claim Free Key →

Request Body Parameters

Field	Type	Required	Default	Description
url	string	required	—	Target SPA or dynamic URL to render.
waitUntil	'domcontentloaded' \| 'load' \| 'networkidle'	optional	'domcontentloaded'	Lifecycle condition to satisfy before DOM serialization.
waitForSelector	string	optional	—	Specific CSS selector to wait for before extraction.
includeHtml	boolean	optional	true	Include the full serialized outerHTML.
extractText	boolean	optional	false	Also return innerText representation.
selector	string	optional	—	Clip output to a specific container element.

Response Schema & Example

200 OK — application/jsonDuration: ~800ms (Cold) / ~8ms (Cached)

{
  "url": "https://news.ycombinator.com",
  "title": "Hacker News",
  "content": "<!DOCTYPE html><html><head>...</head><body><div id=\"root\">...</div></body></html>",
  "durationMs": 410
}

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