sync

Examples — promise chains

The same 11 SDK scenarios as ../async/, written with .then()/.catch() instead of await. Nothing about the SDK changes between the two suites: CaptchaClient returns promises, and these files simply consume them without await.

Setup, API key and the general gotchas are documented once in the parent README — read that first if you haven't.

Two consequences of dropping await are worth knowing before you run anything here:

• Tasks are named, not inline. Each block declares its task in a const (proxylessTask, proxyTask, basicTask, …) and then passes it to captchaSolver.solve(...), which keeps the promise chain readable.
• Blocks start concurrently. In async/, a top-level await makes the proxyless block finish before the with-proxy block begins. Here nothing blocks, so both solve() calls are submitted almost simultaneously and their results arrive in whatever order the API returns them. Two tasks, twice the balance — comment out the block you don't need.

Errors are handled per chain with a trailing .catch(); a failing block does not stop the others.

Table of contents

• File index
• What each file does

File index

File	What it does	Blocks in the file
balance.js	Reads the account balance	single call
recaptcha_v2.js	Solves reCAPTCHA v2	Proxyless · With proxy
recaptcha_v2_enterprise.js	Solves reCAPTCHA v2 Enterprise	Proxyless · With proxy
turnstile.js	Solves Cloudflare Turnstile	Proxyless · With proxy
geetest_v3.js	Fetches a fresh challenge, then solves GeeTest v3	one nested chain
geetest_v4.js	Solves GeeTest v4 via captcha_id	Proxyless · With proxy
yandex_smartcaptcha.js	Solves Yandex SmartCaptcha (token challenge)	Proxyless · With proxy
tencent.js	Solves a Tencent captcha	Proxyless · With proxy
image_to_text.js	Recognises text on a captcha image	Basic · Advanced · With language pool

What each file does

balance.js

Source code · API documentation

captchaSolver.getBalance()
  .then((balance) => console.log('Balance:', balance))

One call resolving to the available amount as a number. No task, no target page, no placeholders — the only file here that runs correctly without editing anything, and therefore the quickest check that your key works.

recaptcha_v2.js

Source code · API documentation

The reference file for the proxyless/with-proxy pattern most other examples repeat. RecaptchaV2Proxyless solves through the service's own IPs; RecaptchaV2 adds proxyType, proxyAddress, proxyPort, proxyLogin and proxyPassword. The client constructor is annotated with the two optional settings — timeout (default 120000 ms) and pollingInterval (default 5000 ms) — and the task shows isInvisible for invisible widgets. Solution: gRecaptchaResponse.

recaptcha_v2_enterprise.js

Source code · API documentation

Same two chains, plus enterprisePayload. Enterprise widgets render through grecaptcha.enterprise.render(), and any extra parameters the site passes there must be forwarded in that object — omit them and the site rejects an otherwise valid token. Solution: gRecaptchaResponse.

A single chain: v3 has no with-proxy variant. minScore is required and controls how hard the task is — 0.3 fastest, 0.7 balanced, 0.9 highest and slowest — so the client is created with timeout: 180000. pageAction should mirror the action the site sets in grecaptcha.execute(). Commented-out lines show isEnterprise and apiDomain for sites loading from recaptcha.net. Solution: gRecaptchaResponse.

turnstile.js

Source code · API documentation

Proxyless and with-proxy chains. The commented optional fields matter more here than elsewhere: action, data (data-cdata) and pagedata (chlPageData, lowercase unlike the rest) are required for Cloudflare Challenge pages. Note the User-Agent rule spelled out in the comments — there's no userAgent input field; the worker picks its own and returns it as result.userAgent, and the browser or bot submitting the token must send that exact one back. Solution: token (plus userAgent).

geetest_v3.js

Source code · API documentation

Structurally the odd one out. challenge is session-specific and must be fresh per task, so the file opens with a fetch(...).then(response => response.json()) chain and nests both solve blocks inside the .then(({ challenge }) => { … }) callback — the tasks cannot be built until the value arrives. This is the clearest place to see what await buys you: the async version expresses the same dependency as three flat statements.

That URL — https://target-site.com/path/to/geetest/init — is a placeholder, so the file does not run end-to-end unmodified. It marks where the fetch belongs in the flow; point it at your real source of challenge first.

The client uses timeout: 300000 and pollingInterval: 10000, GeeTest being among the slowest types. version is omitted since v3 is the default. Solution: challenge, validate, seccode.

geetest_v4.js

Source code · API documentation

Same GeeTestProxyless/GeeTest classes as v3, but v4 identifies the widget differently: no gt, no challenge, instead version: 4 and captcha_id inside initParameters. No pre-fetch is needed, so this file keeps the flat two-chain layout. Same extended timeouts. Solution: captcha_id, lot_number, pass_token, gen_time, captcha_output.

yandex_smartcaptcha.js

Source code · API documentation

The token challenge, proxyless and with proxy. websiteKey is the sitekey from the page source coordinates.js instead — different task class entirely. Solution: token.

tencent.js

Source code · API documentation

Proxyless and with proxy. appId comes from the page source; captchaScript is only needed when the site loads the widget from a non-default script URL. Solution: appid, ret, ticket, randstr.

image_to_text.js

Source code · API documentation

Three chains, no proxy variant, all active. Basic (basicTask) sends the shipped text-captcha.png sample with the character-set hints that match it — numeric: 2 (letters), minLength/maxLength. Advanced (advancedTask) solves a different image entirely, captcha-math.png, using the rest of the hints — phrase, math, comment, and captcha-math-instructions.png passed as imgInstructions. With language pool (languagePoolTask) demonstrates the one API detail that is easy to get wrong: languagePool is the second argument to solve(), not a task field — captchaSolver.solve(languagePoolTask, 'en'), accepting 'en' or 'ru'.

Reads its images via new URL(..., import.meta.url), so the path holds regardless of the working directory and the script runs as-is. Solution: text.

coordinates.js

Source code · API documentation

Three chains, no proxy variant, all active. Basic (basicTask) submits the shipped grid captcha (coordinates-captcha.png) plus a comment telling the worker what to click. Advanced (advancedTask) solves a different image, a real traffic-lights photo (traffic-lights.png), with traffic-lights-instructions.png as imgInstructions and minClicks/maxClicks limits. Yandex SmartCaptcha image mode (yandexTask) reuses the same CoordinatesTask with click-order hint is baked into the image itself, so no separate imgInstructions is passed — this is how the image variant of Yandex SmartCaptcha is solved.

Reads its images via new URL(..., import.meta.url), so the path holds regardless of the working directory and the script runs as-is. Solution: coordinates, an array of { x, y } points.