NSLSolver Node.js SDK

Node.js client for the NSLSolver captcha API. Solves Cloudflare Turnstile, Cloudflare Challenge, Kasada, Akamai Bot Manager, and reCAPTCHA v3. Zero dependencies, TypeScript support, uses native fetch.

Requires Node.js 18+.

Install

npm install nslsolver

Usage

import { NSLSolver } from 'nslsolver';
// or: const { NSLSolver } = require('nslsolver');

const solver = new NSLSolver('your-api-key');

Turnstile

const { token, cost } = await solver.solveTurnstile({
  siteKey: '0x4AAAAAAAB...',
  url: 'https://example.com',
  // action, cdata, proxy, userAgent are optional
});

Challenge

const { cookies, userAgent, cost } = await solver.solveChallenge({
  url: 'https://example.com/protected',
  proxy: 'http://user:pass@host:port',
});

Kasada

const { headers, cost } = await solver.solveKasada({
  url: 'https://example.com/api',
  userAgent: 'Mozilla/5.0 ... Chrome/131.0.0.0 ...',
  uaVersion: 131,
  kasadaConfig: {
    pJsPath: '/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/p.js',
    // fpHost / tlHost are bare hostnames — no scheme, no path.
    fpHost: 'fp.example.com',
    tlHost: 'tl.example.com',
    // cdConstant is optional
  },
  // proxy is optional
});
// headers["x-kpsdk-ct"], headers["x-kpsdk-cd"], etc.

Akamai

const { cookies, cost } = await solver.solveAkamai({
  url: 'https://example.com',
  // Akamai fingerprints the UA — replay with the exact value you submit.
  userAgent: 'Mozilla/5.0 ... Chrome/131.0.0.0 ...',
  // Proxy is required; the _abck cookie is bound to its egress IP.
  proxy: 'http://user:pass@host:port',
});
// cookies["_abck"], cookies["bm_sz"], etc.

reCAPTCHA v3

const { token, cost } = await solver.solveRecaptchaV3({
  siteKey: '6Lc...',
  url: 'https://example.com',
  proxy: 'http://user:pass@host:port', // required
  // action defaults to "verify" server-side when omitted
  action: 'login',
  // set enterprise: true for reCAPTCHA Enterprise
  enterprise: false,
  // userAgent is optional
});

Balance

const { balance, unlimited, allowedTypes, maxCpm, currentCpm, cpmLimit } =
  await solver.getBalance();

// cpmLimit is the max captchas-per-minute for this key.
// currentCpm is how many tokens have been consumed in the rolling minute.

Config

const solver = new NSLSolver('your-api-key', {
  timeout: 60_000,
  maxRetries: 5,
  baseUrl: 'https://api.nslsolver.com',
});

Defaults: 120s timeout, 3 retries.

Errors

All errors extend NSLSolverError. 429 and 503 are retried automatically before throwing.

import { AuthenticationError, InsufficientBalanceError, RateLimitError, SolveError } from 'nslsolver';

try {
  const { token } = await solver.solveTurnstile({ siteKey: '...', url: '...' });
} catch (err) {
  if (err instanceof AuthenticationError)      { /* 401 - bad key */ }
  if (err instanceof InsufficientBalanceError) { /* 402 - top up */ }
  if (err instanceof RateLimitError)           { /* 429 - after retries */ }
  if (err instanceof SolveError)               { /* 400/503 */ }
}

Documentation

For more information, check out the full documentation at https://docs.nslsolver.com

License

MIT