---
title: Quickstart
---

# Quickstart

This guide will help you integrate CaptchaLa CAPTCHA in 5 minutes.

::: tip See it work in 30 seconds
[demo-v1.captcha.la](https://demo-v1.captcha.la) — pure HTML + PHP, MIT-licensed, view-source on every page.

- [popup.html](https://demo-v1.captcha.la/popup.html) — popup mode
- [float.html](https://demo-v1.captcha.la/float.html) — floating widget
- [bind.html](https://demo-v1.captcha.la/bind.html) — bind to button
- [inline.html](https://demo-v1.captcha.la/inline.html) — inline embed
- [server-token.html](https://demo-v1.captcha.la/server-token.html) — server-issued token (anti-replay)
:::


## 1. Create Account

Sign up for a free account in the dashboard

[Sign Up Now →](https://dash.captcha.la/register)

## 2. Create Application

Create an app in the dashboard to get your App Key

## 3. Install SDK

Choose your preferred installation method

```html
<!-- CDN loader (recommended): auto-fallback CDN, ~6 KB gzip -->
<script src="https://cdn.captcha-cdn.net/captchala-loader.js"></script>
```

```bash
# or via npm
npm install captchala
```

## 4. Initialize CAPTCHA

Initialize the CAPTCHA component in your page

```html
<button id="login-btn">Sign in</button>

<script>
loadCaptchala(function () {
  Captchala.init({
    appKey: 'YOUR_APP_KEY',
    product: 'bind',          // popup | float | bind | embed
    action: 'login',
    lang: 'auto',
  })
  .onSuccess(function (res) {
    // res.token starts with pt_ — POST it to your backend
    submitLogin(res.token);
  })
  .onError(function (err) { console.error(err.message); })
  .bindTo('#login-btn');     // popup/bind use bindTo; float/embed use appendTo
});
</script>
```

## 5. Server Verification

Verify the token on your server

```bash
POST https://apiv1.captcha.la/v1/validate
X-App-Key: YOUR_APP_KEY
X-App-Secret: YOUR_APP_SECRET
Content-Type: application/json

{ "pass_token": "<from onSuccess>" }
```

```json
{
  "code": 0,
  "data": {
    "valid": true,
    "action": "login",
    "challenge_id": "ch_xxx",
    "uid": null,
    "risk_score": 12
  }
}
```

::: warning
Always check `data.valid === true` **and** `data.action` matches the scene you expected.
Pass tokens are single-use; the same `pt_xxx` cannot be validated twice.
:::

## Server-issued Token Mode (recommended for production) {#server-token}

For sensitive actions (login, register, payment) we recommend the server-issued token flow: your backend first requests a short-lived server_token, which the browser then uses to initialize the CAPTCHA. This prevents abuse from a leaked app_key.

### When to use

- Recommended: register, login, password reset, payment, points redemption, and any endpoint an attacker can script.
- Optional: casual public forms, search boxes, and low-value interactions where convenience matters more.

### 1. Backend issues server_token

Call /v1/server/challenge/issue from your own server, using the X-App-Key and X-App-Secret headers. Never expose these headers to the browser.

```bash
# Server-side only — never call this from a browser
curl -X POST https://apiv1.captcha.la/v1/server/challenge/issue \
  -H "X-App-Key: YOUR_APP_KEY" \
  -H "X-App-Secret: YOUR_APP_SECRET" \
  -d "action=login&ttl=300&max_uses=1&bind_ip=1.2.3.4"

# → { "code": 0, "data": { "server_token": "sct_...", "expires_in": 300 } }
```

### 2. Frontend renders CaptchaLa with the server_token

Pass the token to your CaptchaLa component. The SDK forwards it to the challenge initialization when initializing the challenge.

```js
// Browser fetches the token from YOUR backend, not from CaptchaLa directly
const { serverToken } = await fetch('/api/captcha/issue').then(r => r.json());

Captchala.init({
  appKey: 'YOUR_APP_KEY',
  serverToken,             // single-use, short-lived
  product: 'popup',
  action: 'login',
})
.appendTo('#captcha-container')
.onSuccess(res => submitForm(res.token));
```

### Security notes

- Never put app_secret in frontend code, mobile apps, or public repositories. It must stay server-side.
- Enable "Require server-issued challenge token" in the dashboard to reject any challenge attempted without a server_token.
- Keep ttl short (300s default, 900s max) and prefer max_uses=1 to reduce the impact of token leakage.

## Next steps

- [Web SDK](./web-sdk)
- [API Reference](./api-reference)