@onecaptcha/sdk

Official Node.js SDK for the OneCaptcha unified captcha-solving gateway.

Zero dependencies. Built-in fetch (Node 18+).
ESM only.
Per-type sync and async helper methods with full JSDoc.

Install

npm install @onecaptcha/sdk

Quick start

import { OneCaptchaClient } from '@onecaptcha/sdk';

const client = new OneCaptchaClient({
  apiKey: process.env.ONECAPTCHA_API_KEY,
});

// Solve a reCAPTCHA v2
const result = await client.solveRecaptchaV2({
  url:     'https://example.com/login',
  sitekey: '6Lc...',
});
console.log(result.token);

// Solve an image captcha — just pass the base64 string
const img = await client.solveImageToText(base64);
console.log(img.text);

Constructor options

Option	Default	Description
`apiKey`	required	Your gateway API key (sent as `X-API-Key`)
`baseUrl`	`https://api.one-captcha.com`	Gateway origin, no trailing slash
`timeout`	`30000`	ms timeout for non-solve calls
`solveTimeout`	`120` (seconds)	Default `X-Timeout` for sync `solve()`. Min 10, max 180.
`pollInterval`	`5000`	ms between polls in `waitForTask`
`pollTimeout`	`180000`	Total ms `waitForTask` waits before giving up
`fetch`	`globalThis.fetch`	Custom fetch implementation (test injection)

Sync solve

One call — the gateway holds the connection open until the solution is ready. Best for most use cases.

// Per-type helper (recommended)
const result = await client.solveRecaptchaV2({ url, sitekey });

// Generic form
const result = await client.solve({
  type: 'recaptcha_v2',
  params: { url, sitekey },
});

Per-type sync helpers

client.solveImageToText(base64)                     // or { body, caseSensitive, ... }
client.solveImageToCoordinates(base64)               // or { body, comment, mode }
client.solveRecaptchaV2({ url, sitekey })
client.solveRecaptchaV2Enterprise({ url, sitekey })
client.solveRecaptchaV3({ url, sitekey, action, minScore })
client.solveRecaptchaV3Enterprise({ url, sitekey, action, minScore })
client.solveFunCaptcha({ url, publicKey, subdomain, data })
client.solveGeeTestV3({ url, gt, challenge })
client.solveGeeTestV4({ url, captchaId })
client.solveTurnstile({ url, sitekey })
client.solveAmazonWaf({ url, key })
client.solveMtCaptcha({ url, sitekey })
client.solveProsopo({ url, sitekey })
client.solveFriendlyCaptcha({ url, sitekey })

Async solve

Submit the task and poll until ready. Use when you need non-blocking submission or want to control the polling loop. Every sync helper has a matching ...Async variant.

// Per-type async helper — submits + polls automatically
const result = await client.solveRecaptchaV2Async({
  url: 'https://example.com',
  sitekey: '6Lc...',
}, { pollInterval: 3000, pollTimeout: 120000 });

console.log(result.token);

// Image OCR async
const img = await client.solveImageToTextAsync(base64);
console.log(img.text);

Per-type async helpers

client.solveImageToTextAsync(base64, waitOpts?)
client.solveImageToCoordinatesAsync(base64, waitOpts?)
client.solveRecaptchaV2Async(params, waitOpts?)
client.solveRecaptchaV2EnterpriseAsync(params, waitOpts?)
client.solveRecaptchaV3Async(params, waitOpts?)
client.solveRecaptchaV3EnterpriseAsync(params, waitOpts?)
client.solveFunCaptchaAsync(params, waitOpts?)
client.solveGeeTestV3Async(params, waitOpts?)
client.solveGeeTestV4Async(params, waitOpts?)
client.solveTurnstileAsync(params, waitOpts?)
client.solveAmazonWafAsync(params, waitOpts?)
client.solveMtCaptchaAsync(params, waitOpts?)
client.solveProsopoAsync(params, waitOpts?)
client.solveFriendlyCaptchaAsync(params, waitOpts?)

waitOpts is optional: { pollInterval?: number, pollTimeout?: number }.

Result

Both sync and async helpers return the same shape:

{
  type: 'recaptcha_v2',
  status: 'ready',
  token: '03AGdBq24...',          // token-based captchas
  text: 'K4ADHP',                 // image_to_text
  coordinates: [...],             // image_to_coordinates
  cost: 0.002990,                 // USD charged
  balanceRemaining: 9.997,        // balance after charge
  rateLimit: { limit, remaining, reset }
}

Fields present depend on the captcha type (token for site-based, text for OCR, coordinates for click-based).

Balance

const { balance, currency } = await client.getBalance();

Errors

Every method throws OneCaptchaError on failure.

import { OneCaptchaError, ERROR_CODES } from '@onecaptcha/sdk';

try {
  await client.solveRecaptchaV2({ url, sitekey });
} catch (err) {
  if (err instanceof OneCaptchaError) {
    err.code              // 'BALANCE_EMPTY' | 'PROVIDER_SITEKEY' | 'UNSOLVABLE' | ...
    err.message           // human-readable
    err.status            // HTTP status
    err.retryable         // boolean — check this before retrying
    err.retryAfter        // seconds to wait (null if not retryable)
    err.balanceRemaining  // null or number
    err.rateLimit         // null or { limit, remaining, reset }
  }
}

ERROR_CODES enumerates all codes, plus two SDK-only codes (SDK_TIMEOUT, SDK_NETWORK) for local failures.

Billing

Per-solve pricing. Each solve request deducts the type's base price from your API key balance. Check current pricing at one-captcha.com.

The post-operation balance is on every response as result.balanceRemaining.

License

MIT