[cdpfleet](https://cdpfleet.com/) / [Browsers](https://cdpfleet.com/browsers) / Firefox

Firefox family · Based on Firefox source; not affiliated with Mozilla

# Firefox, *one socket* away.

The browser build that ships with Playwright, based on Firefox source; not affiliated with Mozilla.

[Open in the code builder](https://cdpfleet.com/docs/builder?browser=firefox)[Reference](https://cdpfleet.com/docs/browsers/firefox)

-   **/firefox/session**launch endpoint
-   **1.60**Playwright client
-   **1**thread headless

## Why Firefox

-   The **Playwright browser build based on Firefox source** (not affiliated with Mozilla) — Gecko instead of Chromium.
-   Sites and tests that need a Gecko engine, or a second engine next to Chromium.
-   Headless by default in the examples (1 thread).

## Versions on the fleet now

**build**150.0.2

One build per release, updated on the fleet as new versions ship.

New majors are announced on [/docs/updates](https://cdpfleet.com/docs/updates).

## Launch it

One HTTPS call to `POST /firefox/session` returns a WebSocket URL; connect to it with Playwright's `firefox.connect()` (client 1.60). A headless session takes 1 thread, a headful one 2.

Firefox: launch, open a page, print its title

 

```node
// npm install playwright@1.60.0
// Browsers run on cdpfleet, so no `npx playwright install` is needed.
import { firefox } from 'playwright';

const KEY = process.env.CDPFLEET_API_KEY;

// 1. Launch the browser
const res = await fetch('https://starter.cdpfleet.com/firefox/session', {
  method: 'POST',
  headers: { 'x-api-key': KEY, 'content-type': 'application/json' },
  body: JSON.stringify({
    proxy: 'http://user:pass@proxy.example.com:8080',
    headless: true,
  }),
});
if (!res.ok) throw new Error(`launch failed: ${res.status} ${await res.text()}`);
const { wsUrl } = await res.json();

// 2. Connect and drive it
const browser = await firefox.connect(wsUrl, { headers: { 'x-api-key': KEY } });
const page = await browser.newPage();
await page.goto('https://example.com');
console.log(await page.title());
await browser.close(); // ends the session and stops billing
```

```python
# pip install playwright==1.60.0 requests
# Browsers run on cdpfleet, so no `playwright install` is needed.
import os
import requests
from playwright.sync_api import sync_playwright

KEY = os.environ["CDPFLEET_API_KEY"]

# 1. Launch the browser
res = requests.post(
    "https://starter.cdpfleet.com/firefox/session",
    headers={"x-api-key": KEY},
    json={
        "proxy": "http://user:pass@proxy.example.com:8080",
        "headless": True,
    },
    timeout=60,
)
res.raise_for_status()
ws_url = res.json()["wsUrl"]

# 2. Connect and drive it
with sync_playwright() as p:
    browser = p.firefox.connect(ws_url, headers={"x-api-key": KEY})
    page = browser.new_page()
    page.goto("https://example.com")
    print(page.title())
    browser.close()  # ends the session and stops billing
```

```java
// Maven: com.microsoft.playwright:playwright:1.60.0  and  com.google.code.gson:gson:2.11.0
// Run with PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1: browsers run on cdpfleet.
import com.google.gson.JsonParser;
import com.microsoft.playwright.*;
import java.net.URI;
import java.net.http.*;
import java.util.Map;

public class Example {
  public static void main(String[] args) throws Exception {
    String key = System.getenv("CDPFLEET_API_KEY");

    // 1. Launch the browser
    String body = """
        {
          "proxy": "http://user:pass@proxy.example.com:8080",
          "headless": true
        }
        """;
    HttpResponse<String> res = HttpClient.newHttpClient().send(
        HttpRequest.newBuilder(URI.create("https://starter.cdpfleet.com/firefox/session"))
            .header("x-api-key", key)
            .header("content-type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(body))
            .build(),
        HttpResponse.BodyHandlers.ofString());
    if (res.statusCode() != 200) {
      throw new RuntimeException("launch failed: " + res.statusCode() + " " + res.body());
    }
    String wsUrl = JsonParser.parseString(res.body()).getAsJsonObject().get("wsUrl").getAsString();

    // 2. Connect and drive it
    try (Playwright playwright = Playwright.create()) {
      Browser browser = playwright.firefox().connect(wsUrl,
          new BrowserType.ConnectOptions().setHeaders(Map.of("x-api-key", key)));
      Page page = browser.newPage();
      page.navigate("https://example.com");
      System.out.println(page.title());
      browser.close(); // ends the session and stops billing
    }
  }
}
```

```csharp
// dotnet add package Microsoft.Playwright --version 1.60.0
// Browsers run on cdpfleet, so no `playwright install` is needed.
using System.Net.Http.Json;
using System.Text;
using System.Text.Json;
using Microsoft.Playwright;

var key = Environment.GetEnvironmentVariable("CDPFLEET_API_KEY")!;

// 1. Launch the browser
using var http = new HttpClient();
http.DefaultRequestHeaders.Add("x-api-key", key);
var body = """
    {
      "proxy": "http://user:pass@proxy.example.com:8080",
      "headless": true
    }
    """;
var res = await http.PostAsync("https://starter.cdpfleet.com/firefox/session",
    new StringContent(body, Encoding.UTF8, "application/json"));
if (!res.IsSuccessStatusCode)
    throw new Exception($"launch failed: {(int)res.StatusCode} {await res.Content.ReadAsStringAsync()}");
var wsUrl = (await res.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("wsUrl").GetString()!;

// 2. Connect and drive it
using var playwright = await Playwright.CreateAsync();
var browser = await playwright.Firefox.ConnectAsync(wsUrl, new BrowserTypeConnectOptions
{
    Headers = new Dictionary<string, string> { ["x-api-key"] = key },
});
var page = await browser.NewPageAsync();
await page.GotoAsync("https://example.com");
Console.WriteLine(await page.TitleAsync());
await browser.CloseAsync(); // ends the session and stops billing
```

```go
// go get github.com/playwright-community/playwright-go@v0.6000.0
//
// One-time driver setup (needs Node.js 18+): playwright-go can no longer download the
// 1.60.0 driver itself, so build it from npm and point PLAYWRIGHT_DRIVER_PATH at it:
//   mkdir -p ~/.cache/pw-driver-1.60.0 && cd ~/.cache/pw-driver-1.60.0 &&
//     curl -sL https://registry.npmjs.org/playwright-core/-/playwright-core-1.60.0.tgz | tar xz &&
//     ln -sf "$(command -v node)" node
//   export PLAYWRIGHT_DRIVER_PATH=~/.cache/pw-driver-1.60.0
// Browsers run on cdpfleet, so no browsers are downloaded (SkipInstallBrowsers).
package main

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"strings"

	"github.com/playwright-community/playwright-go"
)

func main() {
	key := os.Getenv("CDPFLEET_API_KEY")

	// 1. Launch the browser
	body := `{
	  "proxy": "http://user:pass@proxy.example.com:8080",
	  "headless": true
	}`
	req, _ := http.NewRequest("POST", "https://starter.cdpfleet.com/firefox/session", strings.NewReader(body))
	req.Header.Set("x-api-key", key)
	req.Header.Set("content-type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer res.Body.Close()
	if res.StatusCode != http.StatusOK {
		msg, _ := io.ReadAll(res.Body)
		log.Fatalf("launch failed: %s %s", res.Status, msg)
	}
	var session struct {
		WsURL string `json:"wsUrl"`
	}
	if err := json.NewDecoder(res.Body).Decode(&session); err != nil {
		log.Fatal(err)
	}

	// 2. Connect and drive it (Install fetches only the Playwright driver, once)
	opts := &playwright.RunOptions{SkipInstallBrowsers: true}
	if err := playwright.Install(opts); err != nil {
		log.Fatal(err)
	}
	pw, err := playwright.Run(opts)
	if err != nil {
		log.Fatal(err)
	}
	defer pw.Stop()
	browser, err := pw.Firefox.Connect(session.WsURL, playwright.BrowserTypeConnectOptions{
		Headers: map[string]string{"x-api-key": key},
	})
	if err != nil {
		log.Fatal(err)
	}
	page, err := browser.NewPage()
	if err != nil {
		log.Fatal(err)
	}
	if _, err := page.Goto("https://example.com"); err != nil {
		log.Fatal(err)
	}
	title, _ := page.Title()
	fmt.Println(title)
	browser.Close() // ends the session and stops billing
}
```

[This program on GitHub →](https://github.com/cdpfleet/cdpfleet/tree/main/examples/browsers/firefox)

## Launch options

| Option | What it does |
| --- | --- |
| [`proxy_rules`](https://cdpfleet.com/docs/browsers/firefox#opt-proxy_rules) | Send specific destination hosts through specific proxies. |
| [`inactivity_timeout`](https://cdpfleet.com/docs/browsers/firefox#opt-inactivity_timeout) | End the session after this long with no traffic on its WebSocket. |
| [`overall_timeout`](https://cdpfleet.com/docs/browsers/firefox#opt-overall_timeout) | Hard cap on the session's total lifetime, regardless of activity. |
| [`memory`](https://cdpfleet.com/docs/browsers/firefox#opt-memory) | Give the session 2, 3 or 4 times your plan's memory; it counts as that many times the threads. |
| [`downloads`](https://cdpfleet.com/docs/browsers/firefox#opt-downloads) | Keep every file the browser downloads, to fetch after the session. |
| [`vpn_tunnel`](https://cdpfleet.com/docs/browsers/firefox#opt-vpn_tunnel) | VPN Tunnel: UDP/WebRTC full support — all of the browser's traffic, UDP included, goes through the residential exit. |
| [`vpn`](https://cdpfleet.com/docs/browsers/firefox#opt-vpn) | Own network (dedicated plans): send all of the browser's traffic through your own VPN instead of a proxy. |
| [`headless`](https://cdpfleet.com/docs/browsers/firefox#opt-headless) | Run without a display. |
| [`screencast`](https://cdpfleet.com/docs/browsers/firefox#opt-screencast) | Stream the page to your code (Playwright page.screencast). |
| [`screen_size`](https://cdpfleet.com/docs/browsers/firefox#opt-screen_size) | Resolution of the session's own display (headful only). |
| [`keep_alive`](https://cdpfleet.com/docs/browsers/firefox#opt-keep_alive) | Keep the session when your client disconnects (dedicated threads only). |
| [`start_url`](https://cdpfleet.com/docs/browsers/firefox#opt-start_url) | Open this page at launch so the session can be driven in live view with no client connected. |
| [`profile`](https://cdpfleet.com/docs/browsers/firefox#opt-profile) | Restore a saved browser profile and save it again when the session ends. |
| [`record`](https://cdpfleet.com/docs/browsers/firefox#opt-record) | Opt this session out of recording with false. |

Every session also needs a `proxy` — yours, or the [residential proxy](https://cdpfleet.com/residential-proxy).

## Related

Cases, recipes, posts and comparisons about this — updated as new ones are published.

### Reference docs

The details, options and errors.

-   [Firefox reference](https://cdpfleet.com/docs/browsers/firefox)Versions and every launch option.
-   [Quickstart](https://cdpfleet.com/docs/quickstart)Your first session in five minutes.

### Cases 18

Real problems solved end to end, run on production in five languages.

-   [Case 84: Does the TLS fingerprint (JA4) explain which browsers got in? Twelve browsers against six vendors](https://cdpfleet.com/docs/cases/ja4-vs-vendor-verdicts)Each of the twelve browsers from the real-site lab week loads a TLS echo page once, so we know the JA4, peetprint and HTTP/2 fingerprint it sends. Grouped by…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/84-ja4-vs-vendor-verdicts)
-   [Case 80: How many tabs fit in one session, by plan, browser and "memory"](https://cdpfleet.com/docs/cases/tabs-and-memory-by-plan)A long Wikipedia article opened in one new tab after another until the session ends: on Community (2 GB), a shared plan (4 GB) and a dedicated thread (6 GB), in…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/80-tabs-and-memory-by-plan)
-   [Case 77: Kasada and AWS WAF on real sites: twelve browsers, four sites, one exit each](https://cdpfleet.com/docs/cases/kasada-and-aws-waf-by-browser)Two real sites behind Kasada and two behind AWS WAF, loaded once by each of twelve browsers and by a returning Camoufox profile, through one sticky residential exit…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/77-kasada-and-aws-waf-by-browser)
-   [Case 75: HUMAN on real sites: twelve browsers, three sites, one exit each](https://cdpfleet.com/docs/cases/human-real-sites-by-browser)Three real sites behind HUMAN (formerly PerimeterX), chosen from our sweep as easy, medium and hard, loaded once by each of twelve browsers and by a returning…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/75-human-real-sites-by-browser)
-   [Case 73: Akamai on real sites: twelve browsers, three sites, one exit each](https://cdpfleet.com/docs/cases/akamai-real-sites-by-browser)Three real sites behind Akamai Bot Manager, chosen from our sweep as easy, medium and hard, loaded once by each of twelve browsers and by a returning Camoufox…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/73-akamai-real-sites-by-browser)
-   [Case 71: DataDome on real sites: twelve browsers, three sites, one exit each](https://cdpfleet.com/docs/cases/datadome-real-sites-by-browser)Three real sites behind DataDome, chosen from our sweep as easy, medium and hard, loaded once by each of twelve browsers and by a returning Camoufox profile, all…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/71-datadome-real-sites-by-browser)
-   [Case 70: Cloudflare on real sites: twelve browsers, three sites, one exit each](https://cdpfleet.com/docs/cases/cloudflare-real-sites-by-browser)Three real sites behind Cloudflare, chosen from our sweep as easy, medium and hard, loaded once by each of twelve browsers and by a returning Camoufox profile, all…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/70-cloudflare-real-sites-by-browser)
-   [Case 68: CAPTCHA demo pages: what reCAPTCHA v3 scores and hCaptcha show seven browsers, and why a demo can't rank them](https://cdpfleet.com/docs/cases/captcha-scores-by-browser)Google's public reCAPTCHA v3 score demo and hCaptcha's demo widget, loaded once per cell by seven browser setups through your own proxy and a sticky cdpfleet-resi…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/cases/68-captcha-scores-by-browser)

[All cases →](https://cdpfleet.com/docs/cases) 18 match this topic

### Recipes 2

Complete programs for one setup each.

-   [Firefox that stays logged in between sessions](https://cdpfleet.com/docs/examples#firefox-profile)`profile` works on Firefox too: cookies (session ones included) and localStorage are restored at launch and saved when the session ends. Measured on prod with this…[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/examples/recipes/firefox-profile)
-   [Long-running session](https://cdpfleet.com/docs/examples#long-session)Keep a session alive for up to two hours and tolerate five idle minutes. Both are capped by your plan.[Code on GitHub](https://github.com/cdpfleet/cdpfleet/tree/main/examples/recipes/long-session)

### Browser comparisons 2

Measured side by side on the fleet.

-   [Camoufox vs Firefox, headless](https://cdpfleet.com/docs/compare/camoufox-vs-firefox-headless)Headless Firefox and headless Camoufox (both based on Firefox source; not affiliated with Mozilla) side by side: the headless tells a page can read, what Camoufox…
-   [Firefox vs Camoufox](https://cdpfleet.com/docs/compare/firefox-vs-camoufox)Playwright's Firefox build against the anti-detect fork built on it (both based on Firefox source; not affiliated with Mozilla): what Camoufox changes in what a site…

## Read next

[Browsers →](https://cdpfleet.com/browsers)[Camoufox →](https://cdpfleet.com/browsers/camoufox)

---
Source: https://cdpfleet.com/browsers/firefox · Markdown: https://cdpfleet.com/browsers/firefox.md · All docs for AI tools: https://cdpfleet.com/llms.txt