Skip to content

Cloudflare Turnstile action and cData demo

This page's Cloudflare Turnstile widget sets an action, demo_login, and a cData value, demo-session-42. Cloudflare returns both when the token is checked, so the verdict below shows them. A task for this page must send the same two values.

The widget

Live

Check a token from a task

A task's solution.token for this page. It passes once, within 300 seconds of the solve.

This widget's settings

Sitekey0x4AAAAAAFMVDQUY9ZAPO0ni
Mode
managed
Appearance
always
Size
normal
Rendering
implicit
Action
demo_login
cData
demo-session-42
Task
TurnstileTaskProxyless

The verdict

The token goes to this site's API, which asks Cloudflare's siteverify with the widget's secret key. The reply is shown as it came.

No token checked yet

Solve the widget and press Verify, or paste a token a task returned for this page.

success
not checked yet
hostname
not checked yet
challenge_ts
not checked yet
action
not checked yet
cdata
not checked yet
error-codes
not checked yet
Widget
not checked yet
Round trip
not checked yet

Solve this page with the API

The complete createTask request for this page, then getTaskResult every 2 seconds until it is ready, then the result used as the page uses it. Set ZEROCAPTCHA_KEY to your API key.

type
TurnstileTaskProxyless, or TurnstileTask with your proxy
websiteURL
https://zerocaptcha.io/captcha-test/cloudflare-turnstile-action-cdata
websiteKey
0x4AAAAAAFMVDQUY9ZAPO0ni
metadata.action
demo_login
metadata.cdata
demo-session-42
proxy
Only with TurnstileTask: http://user:pass@host:port
callbackUrl
Optional: called with the result when the task ends
Idempotency-Key
A header: sent again within 24 hours, it returns the first task

A task is charged at the listed price when it succeeds; a failed one costs nothing. The same task over REST, POST /v1/tasks, is inSolving Cloudflare Turnstile.

#!/usr/bin/env bash
# Solve this page's Cloudflare Turnstile widget with createTask, then check the token here.
set -euo pipefail
API=${ZEROCAPTCHA_API:-https://api.zerocaptcha.io}
KEY=${ZEROCAPTCHA_KEY:?Set ZEROCAPTCHA_KEY to your API key, zc_live_..., from the dashboard.}

# 1. createTask for this page and its sitekey.
#    metadata holds this widget's data-action and data-cdata: a site that checks them
#    refuses a token solved without them, so copy them from the widget you solve.
#    To solve through your own proxy, make the type TurnstileTask and add
#    proxy: "http://user:pass@proxy.example.net:8080" to the task.
#    CALLBACK_URL, when set, is called with the result when the task ends.
BODY=$(jq -n --arg key "$KEY" --arg callback "${CALLBACK_URL:-}" '{
  clientKey: $key,
  task: {
    type: "TurnstileTaskProxyless",
    websiteURL: "https://zerocaptcha.io/captcha-test/cloudflare-turnstile-action-cdata",
    websiteKey: "0x4AAAAAAFMVDQUY9ZAPO0ni",
    metadata: {action: "demo_login", cdata: "demo-session-42"}
  },
  callbackUrl: (if $callback == "" then null else $callback end)
}')
CREATED=$(curl -sS --fail-with-body "$API/createTask" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d "$BODY")
# errorId 1 is a refusal: errorCode and errorDescription say why.
if [ "$(jq -r .errorId <<<"$CREATED")" != 0 ]; then echo "$CREATED" >&2; exit 1; fi
TASK_ID=$(jq -r .taskId <<<"$CREATED")

# 2. getTaskResult every 2 seconds until the task is ready; errorId 1 means it failed, unpaid.
while :; do
  sleep 2
  RESULT=$(curl -sS --fail-with-body "$API/getTaskResult" \
    -H "Content-Type: application/json" \
    -d "$(jq -n --arg key "$KEY" --arg id "$TASK_ID" '{clientKey: $key, taskId: $id}')")
  if [ "$(jq -r .errorId <<<"$RESULT")" != 0 ]; then echo "$RESULT" >&2; exit 1; fi
  if [ "$(jq -r .status <<<"$RESULT")" = ready ]; then break; fi
done
TOKEN=$(jq -r .solution.token <<<"$RESULT")

# 3. Use solution.token once, within 300 seconds: here, this page's check, which asks
#    Cloudflare's siteverify. Or paste it into the token box on the page.
curl -sS --fail-with-body "$API/v1/demo/verify" \
  -H "Content-Type: application/json" \
  -d "$(jq -n --arg token "$TOKEN" '{widget: "managed", token: $token}')"

What this widget is

action is a short label for what the visitor is doing, up to 32 letters, digits, underscores or dashes. cData is customer data, up to 255 of the same characters, such as a session ID. Both are sent with the widget and come back from siteverify, so the site can refuse a token earned for another form or another session.

A token solved without them is still a token, but a site that compares the action or the cData on its server will refuse it.

Bring a token from elsewhere: the Cloudflare Turnstile token checker.

How to use the result

The task's result is a token: the same value a browser puts in the form's hidden cf-turnstile-response field. Send it where the page's own form sends it, in the same field. On this page that is the check at the top, beside the widget, which asks Cloudflare's siteverify about it with this widget's secret and shows the verdict; a task's token goes in its token box.

A token passes siteverify once, within 300 seconds of the solve. Use it straight away, and solve again for the next submission rather than reusing one.

Check the verdict's action and cdata: they are the values the widget was solved with. A site's server should compare them with what it expects.

How to recognise it on a real site

  • data-action and data-cdata beside data-sitekey, or action and cData in the turnstile.render() options.

  • The page loads https://challenges.cloudflare.com/turnstile/v0/api.js, the only script Cloudflare supports: it must not be copied, proxied or cached.

  • The widget itself is an iframe from challenges.cloudflare.com, under /cdn-cgi/challenge-platform/. Its requests go to Cloudflare, never to the site.

  • Inside a form, the widget adds a hidden input named cf-turnstile-response and puts the token there. The site's server checks it with POST https://challenges.cloudflare.com/turnstile/v0/siteverify.

  • No cookie is set on the site's own domain: the widget's state lives in Cloudflare's iframe.

This page's widget markup
<script src="https://challenges.cloudflare.com/turnstile/v0/api.js" async defer></script>
<div class="cf-turnstile" data-sitekey="0x4AAAAAAFMVDQUY9ZAPO0ni" data-action="demo_login" data-cdata="demo-session-42"></div>
<!-- once solved: <input type="hidden" name="cf-turnstile-response" value="…"> -->

Action and cData questions

Which ZeroCaptcha task solves the Cloudflare Turnstile widget with action and cData?

TurnstileTaskProxyless, or TurnstileTask to solve through your own proxy, with the page's URL and its sitekey, plus action and cdata when the widget sets them. The same task solves every Cloudflare Turnstile widget, whatever its mode or appearance.

What if a task leaves out the action?

The token can still be issued, but siteverify then reports another action, or none, and a site that checks it refuses the token. Send the widget's action and cdata exactly as the page sets them.