> ## Documentation Index > Fetch the complete documentation index at: https://docs.spoolpdf.nandra.dev/llms.txt > Use this file to discover all available pages before exploring further. # Waits, cookies, and auth > SPA waits, extra HTTP headers, cookies, and HTTP Basic auth. ## Wait for the page `wait_delay` is a Go duration (`2s`, `500ms`), max 30s. `wait_for_selector` waits until a matching element exists. `wait_for_expression` waits until a JavaScript expression is truthy (async expressions that return a Promise are awaited). `wait_for_network_idle: true` waits until Chromium reports zero connections for 500ms — skip it on pages that keep a websocket open. ```bash theme={null} curl -sS -o spa.pdf \ -X POST "$SPOOLPDF_BASE_URL/v1/render" \ -H "Authorization: Bearer $SPOOLPDF_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "url": "https://example.com/invoice/preview", "wait_for_selector": "#invoice-ready", "wait_delay": "500ms" }' ``` ```json theme={null} {"html": "…", "wait_for_expression": "window.status === 'ready'"} ``` If the wait never becomes true, the call returns `502` `render_failed`. ## Headers and cookies Do not put `Cookie` in `extra_http_headers`. Use `cookies` (`name`, `value`, and `domain` are required). Hop-by-hop header names are rejected. ```json theme={null} { "url": "https://app.example.com/statement", "extra_http_headers": {"Authorization": "Bearer app-token"}, "cookies": [ {"name": "sid", "value": "abc", "domain": "app.example.com", "http_only": true, "same_site": "Lax"} ] } ``` ## HTTP Basic auth ```json theme={null} {"url": "https://app.example.com/invoice", "auth": {"username": "user", "password": "secret"}} ``` `auth` cannot be combined with `extra_http_headers.Authorization`. ## Fail on HTTP status `raise_for_status: true` fails the render on 3xx/4xx/5xx of the main URL. `false` allows error pages. Omit to keep the default (fail on 4xx/5xx). `emulate_media` is `print` (default) or `screen`.