Virtual Mailbox SandboxPolling Sync

Virtual Email & SMS Web Inbox

Inspect test emails, OTP verification codes, magic links, itemized receipts with Cloudinary attachments, and SMS messages dispatched in your sandbox session.

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Send a test email/SMS or trigger an auth signup to see messages here.

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Select a message from the sidebar to inspect rendered HTML, verify security headers, extract OTP codes, or download Cloudinary attachments.

Virtual Inbox Architecture & Capabilities

Playground API provides a completely zero-configuration, in-memory & cloud-backed virtual communication sandbox. When your backend or frontend sends transactional emails, verification SMS, or password reset instructions, messages are captured in real-time inside your session sandbox instead of delivering to real telecom or email networks.

Automated OTP Extraction

Regex-powered OTP parser automatically identifies 4-8 digit numeric verification codes and magic links in both emails and SMS.

Cloudinary CDN Storage

Email attachments are automatically uploaded and namespaced to playground_api/emails/attachments/<session> and cleaned up on sandbox reset.

Real-Time SSE Sync

Subscribed to Server-Sent Events (/stream/notifications) so the web inbox auto-updates instantly as messages are sent.

Built-in Transactional Templates

You can reference built-in templates by passing the template property when calling POST /api/v1/emails/send along with variable substitutions in data:

Template ID	Description	Interpolated Variables
welcome-verification	Signup welcome email with 6-digit verification code & link	{{name}}, {{otp}}, {{verification_link}}, {{expires_in_minutes}}
password-reset	Secure password reset instructions with security details	{{name}}, {{otp}}, {{reset_link}}, {{ip_address}}, {{device}}
invoice-receipt	Itemized transaction receipt with attachment download	{{name}}, {{invoice_id}}, {{amount}}, {{plan_name}}, {{payment_method}}
2fa-code	High-priority two-factor authentication security code	{{name}}, {{otp}}, {{device}}, {{location}}

Code Examples & Test Automation

Dispatching Emails with Attachments (TypeScript SDK)

typescript

// 1. Send transactional email using TypeScript SDK

import { PlaygroundClient } from 'playground-api';

const client = new PlaygroundClient({

identityToken: 'your_sandbox_identity_token'

});

const email = await client.emails.send({

to: 'developer@example.com',

data: {

otp: '948201',

verification_link: 'https://myapp.com/verify?code=948201',

expires_in_minutes: 15

attachments: [

{

content: 'JVBERi0xLjQKJ...', // Base64 encoded or CDN URL

type: 'application/pdf'

}

]

});

console.log('Email dispatched to virtual sandbox:', email.id);

console.log('Extracted OTP code:', email.otp_code);

Automated E2E Signup OTP Verification (Playwright)

typescript

// 2. Fetch Sandbox Inbox in Automated E2E Tests (Playwright/Cypress)

import { test, expect } from '@playwright/test';

test('verify user signup OTP code', async ({ request }) => {

// Trigger signup on your frontend app

const signupRes = await request.post('http://localhost:3000/api/auth/register', {

data: { name: 'E2E User', username: 'e2e_user', email: 'e2e@example.com' }

});

expect(signupRes.ok()).toBeTruthy();

// Query Playground API Virtual Inbox

const inboxRes = await request.get('https://playground.nileslabs.com/api/v1/inbox?type=email&to=e2e@example.com');

const inboxJson = await inboxRes.json();

const welcomeEmail = inboxJson.data[0];

expect(welcomeEmail).toBeDefined();

// Extract 6-digit OTP code directly from API payload

const otpCode = welcomeEmail.otp_code;

console.log('Automated OTP retrieved:', otpCode);

// Submit OTP to complete verification flow

const verifyRes = await request.post('http://localhost:3000/api/auth/verify-email', {

data: { email: 'e2e@example.com', otp: otpCode }

});

expect(verifyRes.ok()).toBeTruthy();

});

Inbox & Communication REST Endpoints

POST/api/v1/emails/send

Send virtual transactional email

GET/api/v1/emails

List all sent emails for current session

POST/api/v1/sms/send

Send simulated SMS message

GET/api/v1/inbox

List unified email & SMS messages

DELETE/api/v1/inbox

Clear all inbox messages & clean up Cloudinary assets

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