Guide

render_js

Browser Actions

Drive the page before AlterLab extracts it: click buttons, fill and submit forms, pick product variants, scroll feeds, run JavaScript and capture screenshots at any point — all inside one /api/v1/scrape request.

Example outputs

The response samples on this page show the shape of the data AlterLab returns. Values such as prices, URLs and counts are illustrative.

Actions vs Passive Options

Most rendered pages need no actions. Three passive options cover the common cases without scripting a sequence. Reach for actions when the content only appears after the page is interacted with. For worked use cases, see the Browser Actions API overview.

Need	Use
Wait until an element has rendered	`wait_for` (request field, a CSS selector) — see Wait for Selector
Trigger lazy-loaded images and sections	`advanced.scroll_to_load` with `scroll_count`
Hide cookie banners	`advanced.remove_cookie_banners` (on by default) and `advanced.consent`
Click, type, select, hover, wait for a spinner to vanish, read a value mid-flow, screenshot between steps	`advanced.actions`

Request Basics

Pass an ordered list in advanced.actions. Each item has a type and that type's fields.
Actions need a rendered page: advanced.render_js: true is required, otherwise the request is rejected with 422.
At most 20 actions per request. They run sequentially, in the order you list them.
A failed action is reported and skipped; the sequence continues with the next action.

JSON

{
  "url": "https://example.com",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "click", "selector": "#show-all" },
      { "type": "wait_for", "selector": ".results", "state": "visible" }
    ]
  }
}

Action Reference

Selectors are CSS by default. Prefix with // or xpath= to use XPath.

Action type	Fields	Description
wait	`milliseconds` integer (100-30000) Fixed delay in ms; with selector, the visibility timeout `selector` string, default 10000 ms timeout (max 500 chars; CSS, or XPath with // or xpath=) Element to wait for. Provide milliseconds, selector, or both `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Fixed delay, or wait until an element is visible. A selector wait that times out fails the action.
wait_for	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to wait for `state` string, default visible (visible \| hidden \| attached \| detached) hidden / detached wait for the element to disappear (e.g. a spinner) `timeout` integer, default 10000 (1000-30000) Timeout in ms `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Wait for an element to reach a state. Fails on timeout.
click	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to click `timeout_ms` integer, default 10000 (100-30000) Action timeout in ms `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Click an element.
fill	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Input element `value` string, required (max 5000 chars) Value to type into the input `timeout_ms` integer, default 10000 (100-30000) Action timeout in ms `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Fill an input field with a value.
press	`key` string, required (max 50 chars) Key name, e.g. Enter, Tab, Escape, ArrowDown `selector` string (max 500 chars; CSS, or XPath with // or xpath=) Element to focus first; omit to press on the page keyboard `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Press a keyboard key.
scroll	`direction` string, default down (down \| up) Scroll direction `amount` integer, default 1 (1-20) Number of viewport heights	Scroll by a number of viewport heights.
infinite_scroll	`max_scrolls` integer, default 10 (1-50) Maximum scroll iterations `delay` integer, default 1000 (200-5000) Delay between scrolls in ms `end_selector` string (max 500 chars) Stop scrolling once this element exists	Scroll repeatedly until the end of content or max_scrolls is reached.
screenshot	`full_page` boolean, default true Full page, or the viewport only	Capture a screenshot at this point in the sequence (returned as screenshot_url).
evaluate	`script` string, required (max 5120 chars; blocked patterns rejected with 422) JavaScript expression or function body `timeout_ms` integer, default 10000 (100-30000) Action timeout in ms	Run JavaScript in the page. The return value is reported in result.
dismiss_consent	`mode` string, default hide (hide \| accept \| reject) hide leaves consent state unchanged; accept / reject click the CMP button first	Remove the cookie consent overlay from the live page.
select	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) The <select> element `value` string (max 500 chars) Option value attribute. Set exactly one of value or label `label` string (max 500 chars) Option visible label. Set exactly one of value or label `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Choose an option in a <select> element.
hover	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to hover `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Hover over an element (menus, tooltips, lazy content).
click_text	`text` string, required (max 500 chars) Visible text of the element to click `exact` boolean, default false Whole-text, case-sensitive match; default is case-insensitive substring `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Click the element whose visible text matches.
extract	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to read `attribute` string (max 100 chars) Attribute to return (e.g. href); omit to return the visible text `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Read text or an attribute from the first matching element into result.
check	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Checkbox or radio `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Check a checkbox or radio button.
uncheck	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Checkbox `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Uncheck a checkbox.
wait_event	`event` string, default load (load \| domcontentloaded \| networkidle) Load state to wait for `timeout` integer, default 10000 (1000-30000) Timeout in ms	Wait for a page load state (e.g. after a navigation).
snapshot	`format` string, default html (html \| markdown) Capture the rendered HTML or its markdown conversion	Capture the page HTML or markdown at this point (returned as snapshot_url).

Limits

Count: up to 20 actions per request.
Selectors: up to 500 characters.
Scripts: an evaluate script is at most 5120 characters. Scripts that use network or code-loading primitives are rejected with 422 before the job runs. Blocked: fetch, XMLHttpRequest, WebSocket, navigator.sendBeacon, importScripts, eval, Function constructor, dynamic import() / require(), __proto__ and prototype introspection, Reflect.get / Reflect.apply / Reflect.construct, String.fromCharCode, Proxy.
Time budget: the whole action sequence shares a 60 s cumulative budget. Actions that would start after it is spent are not run and report action_budget_exhausted; the page is still extracted.

Ordering

Within one rendered request the steps run in this order:

Navigation and page load.
scroll_to_load, when enabled.
Your actions, in order. A screenshot action captures the page at that point in the sequence.
Content extraction — the returned HTML, text, markdown and structured data reflect the page after your actions.
The request-level advanced.screenshot, then advanced.generate_pdf. Both capture the final state, after every action.

action_results

The response carries one entry per action in action_results, in the order the actions ran.

Field	Type	Description
index	integer	Position of the action in your actions array (0-based)
type	string	Action type that ran
success	boolean	Whether the action completed
error	string \| null	Error message when success is false (e.g. action_budget_exhausted)
result	string \| null	Return value of evaluate and extract actions
screenshot	string \| null	Legacy base64 screenshot; screenshot actions now use screenshot_url
screenshot_url	string \| null	URL of the image captured by a screenshot action
snapshot_url	string \| null	URL of the HTML or markdown captured by a snapshot action
truncated	boolean \| null	True when a snapshot was cut at the size cap
duration_ms	integer \| null	Wall time of the action in ms (0 when not run)

JSON

{
  "status_code": 200,
  "action_results": [
    { "index": 0, "type": "select", "success": true, "error": null, "result": null, "screenshot_url": null },
    { "index": 1, "type": "extract", "success": true, "error": null, "result": "$129.00", "screenshot_url": null },
    { "index": 2, "type": "screenshot", "success": true, "error": null, "result": null,
      "screenshot_url": "https://alterlab.io/downloads/screenshots/example.png" }
  ]
}

Error Behaviour

Validation (422): unknown action type, a missing required field, a value out of range, more than 20 actions, a blocked script pattern, or actions without render_js: true.
Action failure: the entry has success: false and an error message (for example a selector that never appeared). Later actions still run.
Budget exhausted: remaining actions report action_budget_exhausted.
Actions not executed: if the scrape path could not run the actions at all, the job fails with browser_actions_not_executed instead of returning a 200 with empty results.

Pricing

Actions run in the browser tier, $0.004 per request. There is no per-action fee.
Each screenshot action that captures an image adds $0.0002, the same as advanced.screenshot. Failed captures are free.
Other add-ons (PDF, extraction, OCR) are billed as usual — see Pricing.

Recipes

dismiss_consent in hide mode removes the overlay without accepting or rejecting anything.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://news.example.com/article",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "dismiss_consent", "mode": "hide" },
      { "type": "screenshot", "full_page": true }
    ]
  }
}'

Load more and infinite scroll

Click a “Load more” button, wait for the new cards, then keep scrolling until the end marker appears.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://shop.example.com/category/shoes",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "click", "selector": "button.load-more" },
      { "type": "wait_for", "selector": ".product-card:nth-child(48)", "timeout": 10000 },
      { "type": "infinite_scroll", "max_scrolls": 15, "delay": 1000, "end_selector": ".end-of-results" }
    ]
  }
}'

Select a product variant and extract the price

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://shop.example.com/product/runner-2",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "select", "selector": "select#size", "value": "42" },
      { "type": "click_text", "text": "Blue" },
      { "type": "wait_for", "selector": ".price[data-ready]", "state": "visible" },
      { "type": "extract", "selector": ".price" },
      { "type": "extract", "selector": "link[rel=canonical]", "attribute": "href" }
    ]
  }
}'

Press Enter in the input, or replace the press step with a click on the submit button.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://books.example.com",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "fill", "selector": "input[name=q]", "value": "distributed systems" },
      { "type": "press", "key": "Enter", "selector": "input[name=q]" },
      { "type": "wait_event", "event": "domcontentloaded" },
      { "type": "wait_for", "selector": ".search-results .result", "timeout": 15000 }
    ]
  }
}'

Capture a screenshot mid-flow

Screenshot actions capture the page between steps — here before and after switching to yearly billing.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://app.example.com/pricing",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "screenshot", "full_page": false },
      { "type": "click", "selector": "button[data-billing=yearly]" },
      { "type": "wait", "milliseconds": 500 },
      { "type": "screenshot", "full_page": false },
      { "type": "evaluate", "script": "document.querySelectorAll(\".plan\").length" }
    ]
  }
}'

JavaScript Rendering Output Formats

Last updated: June 2026

Guide

render_js

Browser Actions

Example outputs

The response samples on this page show the shape of the data AlterLab returns. Values such as prices, URLs and counts are illustrative.

Actions vs Passive Options

Need	Use
Wait until an element has rendered	`wait_for` (request field, a CSS selector) — see Wait for Selector
Trigger lazy-loaded images and sections	`advanced.scroll_to_load` with `scroll_count`
Hide cookie banners	`advanced.remove_cookie_banners` (on by default) and `advanced.consent`
Click, type, select, hover, wait for a spinner to vanish, read a value mid-flow, screenshot between steps	`advanced.actions`

Request Basics

Pass an ordered list in advanced.actions. Each item has a type and that type's fields.
Actions need a rendered page: advanced.render_js: true is required, otherwise the request is rejected with 422.
At most 20 actions per request. They run sequentially, in the order you list them.
A failed action is reported and skipped; the sequence continues with the next action.

JSON

{
  "url": "https://example.com",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "click", "selector": "#show-all" },
      { "type": "wait_for", "selector": ".results", "state": "visible" }
    ]
  }
}

Action Reference

Selectors are CSS by default. Prefix with // or xpath= to use XPath.

Action type	Fields	Description
wait	`milliseconds` integer (100-30000) Fixed delay in ms; with selector, the visibility timeout `selector` string, default 10000 ms timeout (max 500 chars; CSS, or XPath with // or xpath=) Element to wait for. Provide milliseconds, selector, or both `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Fixed delay, or wait until an element is visible. A selector wait that times out fails the action.
wait_for	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to wait for `state` string, default visible (visible \| hidden \| attached \| detached) hidden / detached wait for the element to disappear (e.g. a spinner) `timeout` integer, default 10000 (1000-30000) Timeout in ms `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Wait for an element to reach a state. Fails on timeout.
click	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to click `timeout_ms` integer, default 10000 (100-30000) Action timeout in ms `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Click an element.
fill	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Input element `value` string, required (max 5000 chars) Value to type into the input `timeout_ms` integer, default 10000 (100-30000) Action timeout in ms `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Fill an input field with a value.
press	`key` string, required (max 50 chars) Key name, e.g. Enter, Tab, Escape, ArrowDown `selector` string (max 500 chars; CSS, or XPath with // or xpath=) Element to focus first; omit to press on the page keyboard `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Press a keyboard key.
scroll	`direction` string, default down (down \| up) Scroll direction `amount` integer, default 1 (1-20) Number of viewport heights	Scroll by a number of viewport heights.
infinite_scroll	`max_scrolls` integer, default 10 (1-50) Maximum scroll iterations `delay` integer, default 1000 (200-5000) Delay between scrolls in ms `end_selector` string (max 500 chars) Stop scrolling once this element exists	Scroll repeatedly until the end of content or max_scrolls is reached.
screenshot	`full_page` boolean, default true Full page, or the viewport only	Capture a screenshot at this point in the sequence (returned as screenshot_url).
evaluate	`script` string, required (max 5120 chars; blocked patterns rejected with 422) JavaScript expression or function body `timeout_ms` integer, default 10000 (100-30000) Action timeout in ms	Run JavaScript in the page. The return value is reported in result.
dismiss_consent	`mode` string, default hide (hide \| accept \| reject) hide leaves consent state unchanged; accept / reject click the CMP button first	Remove the cookie consent overlay from the live page.
select	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) The <select> element `value` string (max 500 chars) Option value attribute. Set exactly one of value or label `label` string (max 500 chars) Option visible label. Set exactly one of value or label `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Choose an option in a <select> element.
hover	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to hover `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Hover over an element (menus, tooltips, lazy content).
click_text	`text` string, required (max 500 chars) Visible text of the element to click `exact` boolean, default false Whole-text, case-sensitive match; default is case-insensitive substring `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Click the element whose visible text matches.
extract	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Element to read `attribute` string (max 100 chars) Attribute to return (e.g. href); omit to return the visible text `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Read text or an attribute from the first matching element into result.
check	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Checkbox or radio `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Check a checkbox or radio button.
uncheck	`selector` string, required (max 500 chars; CSS, or XPath with // or xpath=) Checkbox `frame` string \| string[] (max 500 chars per selector; up to the supported nesting depth) Selector of the <iframe> holding the target; a list targets nested frames, outermost first	Uncheck a checkbox.
wait_event	`event` string, default load (load \| domcontentloaded \| networkidle) Load state to wait for `timeout` integer, default 10000 (1000-30000) Timeout in ms	Wait for a page load state (e.g. after a navigation).
snapshot	`format` string, default html (html \| markdown) Capture the rendered HTML or its markdown conversion	Capture the page HTML or markdown at this point (returned as snapshot_url).

Limits

Count: up to 20 actions per request.
Selectors: up to 500 characters.
Scripts: an evaluate script is at most 5120 characters. Scripts that use network or code-loading primitives are rejected with 422 before the job runs. Blocked: fetch, XMLHttpRequest, WebSocket, navigator.sendBeacon, importScripts, eval, Function constructor, dynamic import() / require(), __proto__ and prototype introspection, Reflect.get / Reflect.apply / Reflect.construct, String.fromCharCode, Proxy.
Time budget: the whole action sequence shares a 60 s cumulative budget. Actions that would start after it is spent are not run and report action_budget_exhausted; the page is still extracted.

Ordering

Within one rendered request the steps run in this order:

Navigation and page load.
scroll_to_load, when enabled.
Your actions, in order. A screenshot action captures the page at that point in the sequence.
Content extraction — the returned HTML, text, markdown and structured data reflect the page after your actions.
The request-level advanced.screenshot, then advanced.generate_pdf. Both capture the final state, after every action.

action_results

The response carries one entry per action in action_results, in the order the actions ran.

Field	Type	Description
index	integer	Position of the action in your actions array (0-based)
type	string	Action type that ran
success	boolean	Whether the action completed
error	string \| null	Error message when success is false (e.g. action_budget_exhausted)
result	string \| null	Return value of evaluate and extract actions
screenshot	string \| null	Legacy base64 screenshot; screenshot actions now use screenshot_url
screenshot_url	string \| null	URL of the image captured by a screenshot action
snapshot_url	string \| null	URL of the HTML or markdown captured by a snapshot action
truncated	boolean \| null	True when a snapshot was cut at the size cap
duration_ms	integer \| null	Wall time of the action in ms (0 when not run)

JSON

{
  "status_code": 200,
  "action_results": [
    { "index": 0, "type": "select", "success": true, "error": null, "result": null, "screenshot_url": null },
    { "index": 1, "type": "extract", "success": true, "error": null, "result": "$129.00", "screenshot_url": null },
    { "index": 2, "type": "screenshot", "success": true, "error": null, "result": null,
      "screenshot_url": "https://alterlab.io/downloads/screenshots/example.png" }
  ]
}

Error Behaviour

Validation (422): unknown action type, a missing required field, a value out of range, more than 20 actions, a blocked script pattern, or actions without render_js: true.
Action failure: the entry has success: false and an error message (for example a selector that never appeared). Later actions still run.
Budget exhausted: remaining actions report action_budget_exhausted.
Actions not executed: if the scrape path could not run the actions at all, the job fails with browser_actions_not_executed instead of returning a 200 with empty results.

Pricing

Actions run in the browser tier, $0.004 per request. There is no per-action fee.
Each screenshot action that captures an image adds $0.0002, the same as advanced.screenshot. Failed captures are free.
Other add-ons (PDF, extraction, OCR) are billed as usual — see Pricing.

Recipes

dismiss_consent in hide mode removes the overlay without accepting or rejecting anything.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://news.example.com/article",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "dismiss_consent", "mode": "hide" },
      { "type": "screenshot", "full_page": true }
    ]
  }
}'

Load more and infinite scroll

Click a “Load more” button, wait for the new cards, then keep scrolling until the end marker appears.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://shop.example.com/category/shoes",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "click", "selector": "button.load-more" },
      { "type": "wait_for", "selector": ".product-card:nth-child(48)", "timeout": 10000 },
      { "type": "infinite_scroll", "max_scrolls": 15, "delay": 1000, "end_selector": ".end-of-results" }
    ]
  }
}'

Select a product variant and extract the price

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://shop.example.com/product/runner-2",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "select", "selector": "select#size", "value": "42" },
      { "type": "click_text", "text": "Blue" },
      { "type": "wait_for", "selector": ".price[data-ready]", "state": "visible" },
      { "type": "extract", "selector": ".price" },
      { "type": "extract", "selector": "link[rel=canonical]", "attribute": "href" }
    ]
  }
}'

Press Enter in the input, or replace the press step with a click on the submit button.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://books.example.com",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "fill", "selector": "input[name=q]", "value": "distributed systems" },
      { "type": "press", "key": "Enter", "selector": "input[name=q]" },
      { "type": "wait_event", "event": "domcontentloaded" },
      { "type": "wait_for", "selector": ".search-results .result", "timeout": 15000 }
    ]
  }
}'

Capture a screenshot mid-flow

Screenshot actions capture the page between steps — here before and after switching to yearly billing.

Bash

curl -X POST https://api.alterlab.io/api/v1/scrape \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "url": "https://app.example.com/pricing",
  "advanced": {
    "render_js": true,
    "actions": [
      { "type": "screenshot", "full_page": false },
      { "type": "click", "selector": "button[data-billing=yearly]" },
      { "type": "wait", "milliseconds": 500 },
      { "type": "screenshot", "full_page": false },
      { "type": "evaluate", "script": "document.querySelectorAll(\".plan\").length" }
    ]
  }
}'

JavaScript Rendering Output Formats

Last updated: June 2026

Browser Actions

Actions vs Passive Options

Request Basics

Action Reference

Limits

Ordering

action_results

Error Behaviour

Pricing

Recipes

Hide a consent overlay before a screenshot

Load more and infinite scroll

Select a product variant and extract the price

Fill and submit a search form

Capture a screenshot mid-flow

Browser Actions

Actions vs Passive Options

Request Basics

Action Reference

Limits

Ordering

action_results

Error Behaviour

Pricing

Recipes

Hide a consent overlay before a screenshot

Load more and infinite scroll

Select a product variant and extract the price

Fill and submit a search form

Capture a screenshot mid-flow