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Custom HTTP Headers
PRO

Secrets stay out of URLs. Pass headers on the HTTP layer, and any x-api-header-* is forwarded to the target fetch — cookies and tokens never touch the query string.

Overview

Headers ride the HTTP layer.

The headers option travels as real request headers — never in the URL. The API forwards any x-api-header-<name> to the target fetch as <name>, so a session cookie becomes the target’s cookie header. Your apiKey rides the same way, as x-api-key.
  • headers travel as HTTP request headers — never query params
  • x-api-header-cookie → forwarded to the target as cookie
  • apiKey is sent as x-api-key, never in the URL
  • Compose with proxy to authenticate behind an unblocker
  • Secrets stay out of logs, history and shareable links
Parameters

How headers are routed.

Examples

Forward what the target needs.

x-api-header-cookie reaches the target as cookie.
Forward a session cookie
import createClient from 'microlink.io'

const microlink = createClient({
  apiKey: process.env.MICROLINK_API_KEY
})

const markdown = await microlink.markdown(
  'https://x.com/some/article',
  { headers: { 'x-api-header-cookie': 'auth_token=…' } }
)
Related features

Authenticate and reach targets.

Proxy Resolution

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Automatically bypass Cloudflare, DataDome, Akamai and more. We handle the hard part.

Antibot Detection

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Request Isolation

One ephemeral browser per call. SSRF blocked before navigation.

Web Scraping

Extract structured JSON from any webpage using CSS selectors. URL → JSON in one request.

FAQ

Why not just put secrets in the URL?

URLs leak. They land in server logs, browser history, and shared links. Send the headers option on the HTTP layer instead, so cookies and tokens never appear in the query string.

How does x-api-header-* work?

The API forwards any request header prefixed with x-api-header- to the target fetch with the prefix stripped. So x-api-header-cookie becomes the target’s cookie header, and x-api-header-authorization becomes authorization.

How is my apiKey sent?

The client sends your apiKey as the x-api-key request header, never in the URL. Pass it once to createClient({ apiKey }) and every call is authenticated.

Do forwarded headers work on the free plan?

Standard request headers work on any plan. Forwarding x-api-header-* secrets to the target fetch is a Pro capability, since it typically pairs with authenticated or proxied requests.

Can I forward headers and use a proxy together?

Yes. headers compose with proxy on the same request, so one call can route through a residential IP and still forward a session cookie to authenticate on the target.