The cloud browser API for AI agents.

Browser automation for AI agents, in four calls.

The setup at the top of the panel never changes. Pick a call to see what it is for, what you write, and what comes back. Copy takes the setup, the call and the close together, so it runs as pasted.

import { SpiderBrowser } from "spider-browser"

const browser = new SpiderBrowser({
  apiKey: process.env.SPIDER_API_KEY,
  // act, extract and agent run on a model key you supply
  llm: { provider: "openai", model: "gpt-4o", apiKey: process.env.OPENAI_API_KEY },
})
await browser.init()
await browser.goto("https://shop.example/headphones")

await browser.act("Sort the results by price, low to high")
await browser.act("Open the first product")

await browser.close()

act   "Sort the results by price, low to high"
      matched  select[name="sort"]      chose "price-asc"
      page     36 results, cheapest first

act   "Open the first product"
      matched  a.product-card:first-child   click
      page     /headphones/studio-wired

const actions = await browser.observe("Ways to narrow these results")

// no instruction: every interactive element, no model call
const all = await browser.observe()

await browser.close()

[
  { selector: "select[name=\"sort\"]", tag: "select", type: "select-one",
    text: "Featured", rect: { x: 812, y: 164, width: 180, height: 36 }, score: 0.94 },
  { selector: "input#in-stock", tag: "input", type: "checkbox",
    text: "In stock only", rect: { x: 32, y: 228, width: 18, height: 18 }, score: 0.88 },
  { selector: "button[data-filter=\"wired\"]", tag: "button", type: "button",
    text: "Wired", rect: { x: 32, y: 276, width: 96, height: 32 }, score: 0.71 }
]

import { z } from "zod"

const Products = z.array(z.object({
  name: z.string(),
  price: z.number(),
  inStock: z.boolean(),
}))

const products = await browser.extract(
  "Every product on the page with its price and stock status",
  { schema: Products },
)

await browser.close()

[
  { name: "Studio Wired",   price: 24,  inStock: true },
  { name: "Commute ANC",    price: 89,  inStock: true },
  { name: "Reference Open", price: 349, inStock: false }
]

const result = await browser.agent({ maxRounds: 12 }).execute(
  "Find the cheapest in-stock headphones and return the name, price and URL"
)

await browser.close()

round 1   observe   36 products, sort control found
round 2   act       sort by price, low to high
round 3   act       open "Studio Wired"
round 4   extract   name, price, url

{
  done: true,
  rounds: 4,
  label: "Cheapest in-stock headphones",
  extracted: { name: "Studio Wired", price: 24,
               url: "https://shop.example/headphones/studio-wired" }
}

What the session handles for you.

1. Ready before you ask.

   init() attaches to a browser process that is already running, so your first command goes out without waiting for a launch. close() drops the connection; the server disposes that session's contexts and targets and keeps the process warm for the next caller.

   init()

   attach to a warm process

   close()

   dispose contexts, keep the process

   record: true

   session video, +15% compute

2. Act on the page, then bring data back.

   Four natural-language calls sit on top of a full page API. observe() needs no model. act(), extract() and agent() run on the model key you configure, and extract() returns JSON in the zod schema you pass.

   page

   click, fill, type, press, hover, scroll

   wait

   selector, navigation, network idle

   read

   content, screenshot, extractFields

3. The session handles blocked pages.

   CAPTCHA solving is on unless you turn it off, and country picks the exit address. The 999-URL run below is the published record: every URL, its domain and its outcome.

   999 urls

   999 passed, 254 domains

   run

   2026-02-14, published set

   Dataset and results ↗

Anti-bot pass rate and latency, measured.

Spider passed 79 of 80 anti-bot tasks on Stealth Bench V1 on Sep 18, 2026, the top score of the 8 cloud browsers on the board. A session connects in under a second, and a plain page loads a quarter second after that. Every figure here names its run.

99%

Stealth Bench V1 79 of 80 anti-bot tasks · Sep 18, 2026

0.9s

to connect socket open, key accepted, protocol answering · median · Sep 14, 2026

238ms

page load, once attached example.com to domcontentloaded · median · Sep 14, 2026

Pick a way in.

The SDK is the whole product: the page API and the four calls. A Playwright or Puppeteer script connects to the same session over CDP and keeps its own API.

• TypeScript

  npm install spider-browser

  copy npm ↗
• Python

  pip install spider-browser

  copy PyPI ↗
• Rust

  cargo add spider-browser

  copy crates.io ↗

import { SpiderBrowser } from "spider-browser"
import { z } from "zod"

const browser = new SpiderBrowser({
  apiKey: process.env.SPIDER_API_KEY,
  country: "DE", // exit from a German address
  llm: { provider: "openai", model: "gpt-4o", apiKey: process.env.OPENAI_API_KEY },
})

try {
  await browser.init()
  await browser.goto("https://shop.example/headphones")
  const products = await browser.extract("Every product name and price", {
    schema: z.array(z.object({ name: z.string(), price: z.number() })),
  })
  console.log(products.length, "products, first:", products[0])
} finally {
  await browser.close()
}

import { chromium } from "playwright"

const browser = await chromium.connectOverCDP(
  `wss://browser.spider.cloud/v1/browser?token=${process.env.SPIDER_API_KEY}`
)
const page = await browser.newPage()
await page.goto("https://shop.example/headphones")
console.log(await page.title())
await browser.close()

• MCP

  Browser tools for Claude, Cursor or any MCP client: open, navigate, click, fill, screenshot, content, and one natural-language step. The four SDK calls are not in the MCP tool set.

  MCP server
• Desktop

  The same browser as an app for macOS on Apple silicon, Windows and Linux.

  macOS Windows Linux

Pay for what a session uses.

Minutes count from init() to close() and are pro-rated to the millisecond, elapsed time over 60,000 as credits, billed every 3 seconds while the session is open. One credit is $0.0001. Recording multiplies the compute term by 1.15 and leaves bandwidth alone. Your model provider bills the model calls that act(), extract() and agent() make; Spider does not. No monthly minimum. The whole meter, constants included, is in the pricing guide .

Questions.