From 7ef38a5e0364ef97d94058d58ebf0e35a2086d64 Mon Sep 17 00:00:00 2001
From: mohiit1502 <mohiit1502@gmail.com>
Date: Wed, 7 Jan 2026 21:12:06 +0530
Subject: [PATCH] feat: initial @armco/mesa-sdk with flexible mailConfig

---
 .gitignore    |   7 ++
 README.md     | 297 ++++++++++++++++++++++++++++++++++++++++++++++++++
 package.json  |  49 +++++++++
 src/client.ts | 245 +++++++++++++++++++++++++++++++++++++++++
 src/errors.ts |  57 ++++++++++
 src/index.ts  |  12 ++
 src/types.ts  | 192 ++++++++++++++++++++++++++++++++
 tsconfig.json |  25 +++++
 8 files changed, 884 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100644 package.json
 create mode 100644 src/client.ts
 create mode 100644 src/errors.ts
 create mode 100644 src/index.ts
 create mode 100644 src/types.ts
 create mode 100644 tsconfig.json

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..572f5e3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+node_modules/
+dist/
+*.log
+.env
+.env.local
+.DS_Store
+coverage/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..6e50340
--- /dev/null
+++ b/README.md
@@ -0,0 +1,297 @@
+# @armco/mesa-sdk
+
+Official Node.js SDK for the Mesa/Sandesh Email Platform.
+
+## Installation
+
+```bash
+npm install @armco/mesa-sdk
+# or
+yarn add @armco/mesa-sdk
+# or
+pnpm add @armco/mesa-sdk
+```
+
+## Quick Start
+
+```typescript
+import { MesaClient } from '@armco/mesa-sdk';
+
+const mesa = new MesaClient({
+  apiKey: process.env.MESA_API_KEY!,
+});
+
+await mesa.send({
+  from: { email: 'noreply@example.com', name: 'My App' },
+  to: 'user@example.com',
+  subject: 'Welcome!',
+  html: '<h1>Hello World</h1>',
+});
+```
+
+## Configuration
+
+### Basic Configuration
+
+```typescript
+const mesa = new MesaClient({
+  apiKey: 'your-api-key',           // Required
+  baseUrl: 'https://custom.api.url', // Optional (default: https://api.sandesh.armco.dev)
+  timeout: 30000,                    // Optional (default: 30000ms)
+  retries: 3,                        // Optional (default: 3)
+});
+```
+
+### Mail Configuration
+
+The `mailConfig` object allows you to set default email settings. **This is a flexible JSON config** - new settings added to Sandesh can be passed here without SDK updates.
+
+```typescript
+const mesa = new MesaClient({
+  apiKey: process.env.MESA_API_KEY!,
+  mailConfig: {
+    // Core settings (typed)
+    defaultFrom: { email: 'noreply@example.com', name: 'My App' },
+    defaultReplyTo: { email: 'support@example.com' },
+    trackClicks: true,
+    trackOpens: true,
+    trackingDomain: 'track.example.com',
+    defaultTags: ['transactional'],
+    sandbox: false,
+    ipPool: 'dedicated-pool',
+    sendTimeOptimization: true,
+
+    // Any additional config fields (forward compatible)
+    customField: 'value',
+    newFeatureFlag: true,
+  },
+});
+```
+
+#### Available Mail Config Options
+
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `defaultFrom` | `EmailAddress` | - | Default sender address |
+| `defaultReplyTo` | `EmailAddress` | - | Default reply-to address |
+| `trackClicks` | `boolean` | `true` | Enable click tracking |
+| `trackOpens` | `boolean` | `true` | Enable open tracking |
+| `trackingDomain` | `string` | - | Custom tracking domain |
+| `defaultTags` | `string[]` | - | Tags applied to all emails |
+| `sandbox` | `boolean` | `false` | Sandbox mode (emails logged, not sent) |
+| `ipPool` | `string` | - | Dedicated IP pool name |
+| `sendTimeOptimization` | `boolean` | `false` | AI-powered send time optimization |
+| `[key: string]` | `unknown` | - | Any additional config for future features |
+
+## Sending Emails
+
+### Basic Send
+
+```typescript
+const response = await mesa.send({
+  to: 'user@example.com',
+  subject: 'Hello',
+  html: '<p>Welcome to our platform!</p>',
+  text: 'Welcome to our platform!',
+});
+
+console.log('Email queued:', response.id);
+```
+
+### Multiple Recipients
+
+```typescript
+await mesa.send({
+  to: [
+    { email: 'user1@example.com', name: 'User One' },
+    { email: 'user2@example.com', name: 'User Two' },
+  ],
+  cc: 'manager@example.com',
+  bcc: ['audit@example.com'],
+  subject: 'Team Update',
+  html: '<p>Important announcement...</p>',
+});
+```
+
+### Using Templates
+
+```typescript
+await mesa.send({
+  to: 'user@example.com',
+  subject: 'Order Confirmation',
+  templateId: 'order-confirmation',
+  templateData: {
+    orderNumber: 'ORD-12345',
+    items: [
+      { name: 'Widget', quantity: 2, price: 29.99 },
+    ],
+    total: 59.98,
+  },
+});
+```
+
+### With Attachments
+
+```typescript
+import { readFileSync } from 'fs';
+
+await mesa.send({
+  to: 'user@example.com',
+  subject: 'Your Invoice',
+  html: '<p>Please find your invoice attached.</p>',
+  attachments: [
+    {
+      filename: 'invoice.pdf',
+      content: readFileSync('./invoice.pdf').toString('base64'),
+      contentType: 'application/pdf',
+    },
+  ],
+});
+```
+
+### Scheduled Send
+
+```typescript
+await mesa.send({
+  to: 'user@example.com',
+  subject: 'Reminder',
+  html: '<p>Don\'t forget about your appointment!</p>',
+  scheduledAt: '2024-01-15T09:00:00Z',
+});
+```
+
+### Override Tracking per Email
+
+```typescript
+await mesa.send({
+  to: 'user@example.com',
+  subject: 'Sensitive Information',
+  html: '<p>Your password reset link...</p>',
+  tracking: {
+    clicks: false,  // Disable click tracking for this email
+    opens: false,   // Disable open tracking for this email
+  },
+});
+```
+
+## Batch Sending
+
+```typescript
+const responses = await mesa.sendBatch([
+  { to: 'user1@example.com', subject: 'Hello User 1', html: '...' },
+  { to: 'user2@example.com', subject: 'Hello User 2', html: '...' },
+  { to: 'user3@example.com', subject: 'Hello User 3', html: '...' },
+]);
+
+responses.forEach((res) => console.log('Sent:', res.id));
+```
+
+## Check Email Status
+
+```typescript
+const status = await mesa.getStatus('email-id-here');
+console.log(status);
+```
+
+## Webhook Handling
+
+### Verify Webhook Signature
+
+```typescript
+import express from 'express';
+
+const app = express();
+
+app.post('/webhooks/mesa', express.raw({ type: 'application/json' }), (req, res) => {
+  const signature = req.headers['x-mesa-signature'] as string;
+  const payload = req.body.toString();
+
+  if (!mesa.verifyWebhook(payload, signature, process.env.WEBHOOK_SECRET!)) {
+    return res.status(401).send('Invalid signature');
+  }
+
+  const event = mesa.parseWebhook(payload);
+
+  switch (event.event) {
+    case 'email.delivered':
+      console.log('Email delivered:', event.messageId);
+      break;
+    case 'email.bounced':
+      console.log('Email bounced:', event.messageId, event.data);
+      break;
+    case 'email.opened':
+      console.log('Email opened:', event.messageId);
+      break;
+    case 'email.clicked':
+      console.log('Link clicked:', event.data.url);
+      break;
+  }
+
+  res.status(200).send('OK');
+});
+```
+
+## Runtime Configuration Updates
+
+```typescript
+// Update mail config at runtime
+mesa.updateMailConfig({
+  sandbox: true, // Enable sandbox mode
+});
+
+// Get current config
+const config = mesa.getMailConfig();
+```
+
+## Error Handling
+
+```typescript
+import { MesaClient, MesaAPIError, MesaValidationError } from '@armco/mesa-sdk';
+
+try {
+  await mesa.send({ /* ... */ });
+} catch (error) {
+  if (error instanceof MesaValidationError) {
+    console.error('Validation error:', error.message, 'Field:', error.field);
+  } else if (error instanceof MesaAPIError) {
+    console.error('API error:', error.message);
+    console.error('Status:', error.statusCode);
+    console.error('Code:', error.code);
+    console.error('Details:', error.details);
+  } else {
+    console.error('Unknown error:', error);
+  }
+}
+```
+
+## TypeScript Support
+
+Full TypeScript support with exported types:
+
+```typescript
+import type {
+  MesaConfig,
+  MailConfig,
+  SendEmailOptions,
+  SendEmailResponse,
+  EmailAddress,
+  Attachment,
+  WebhookEvent,
+  WebhookPayload,
+} from '@armco/mesa-sdk';
+```
+
+## Environment Variables
+
+Recommended setup:
+
+```bash
+# .env
+MESA_API_KEY=your-api-key
+MESA_API_URL=https://api.sandesh.armco.dev  # Optional
+WEBHOOK_SECRET=your-webhook-secret
+```
+
+## License
+
+MIT
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..0019a46
--- /dev/null
+++ b/package.json
@@ -0,0 +1,49 @@
+{
+  "name": "@armco/mesa-sdk",
+  "version": "1.0.0",
+  "description": "Official Node.js SDK for Sandesh/Mesa Email Platform",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "exports": {
+    ".": {
+      "import": "./dist/index.mjs",
+      "require": "./dist/index.js",
+      "types": "./dist/index.d.ts"
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "tsup src/index.ts --format cjs,esm --dts",
+    "dev": "tsup src/index.ts --format cjs,esm --dts --watch",
+    "test": "vitest",
+    "lint": "eslint src --ext .ts",
+    "prepublishOnly": "npm run build"
+  },
+  "keywords": [
+    "email",
+    "sandesh",
+    "mesa",
+    "armco",
+    "smtp",
+    "transactional-email",
+    "email-api"
+  ],
+  "author": "Armco",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://gitea.armco.dev/Restruct-Corporate-Advantage/mesa-client-sdk"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "@types/node": "^20.10.6",
+    "tsup": "^8.0.1",
+    "typescript": "^5.3.3",
+    "vitest": "^1.1.0"
+  },
+  "engines": {
+    "node": ">=18.0.0"
+  }
+}
diff --git a/src/client.ts b/src/client.ts
new file mode 100644
index 0000000..efd548d
--- /dev/null
+++ b/src/client.ts
@@ -0,0 +1,245 @@
+import { MesaAPIError, MesaValidationError } from './errors';
+import type {
+  MesaConfig,
+  MailConfig,
+  SendEmailOptions,
+  SendEmailResponse,
+  EmailAddress,
+  WebhookPayload,
+} from './types';
+
+const DEFAULT_BASE_URL = 'https://api.sandesh.armco.dev';
+const DEFAULT_TIMEOUT = 30000;
+const DEFAULT_RETRIES = 3;
+
+/**
+ * Mesa Email SDK Client
+ * 
+ * @example
+ * ```typescript
+ * const mesa = new MesaClient({
+ *   apiKey: 'your-api-key',
+ *   mailConfig: {
+ *     defaultFrom: { email: 'noreply@example.com', name: 'My App' },
+ *     trackClicks: true,
+ *     trackOpens: true,
+ *   }
+ * });
+ * 
+ * await mesa.send({
+ *   to: 'user@example.com',
+ *   subject: 'Hello',
+ *   html: '<h1>Welcome!</h1>'
+ * });
+ * ```
+ */
+export class MesaClient {
+  private readonly apiKey: string;
+  private readonly baseUrl: string;
+  private readonly timeout: number;
+  private readonly retries: number;
+  private readonly mailConfig: MailConfig;
+
+  constructor(config: MesaConfig) {
+    if (!config.apiKey) {
+      throw new MesaValidationError('API key is required', 'apiKey');
+    }
+
+    this.apiKey = config.apiKey;
+    this.baseUrl = (config.baseUrl || DEFAULT_BASE_URL).replace(/\/$/, '');
+    this.timeout = config.timeout || DEFAULT_TIMEOUT;
+    this.retries = config.retries || DEFAULT_RETRIES;
+    this.mailConfig = config.mailConfig || {};
+  }
+
+  /**
+   * Send an email
+   */
+  async send(options: SendEmailOptions): Promise<SendEmailResponse> {
+    const payload = this.buildSendPayload(options);
+    return this.request<SendEmailResponse>('POST', '/v1/emails', payload);
+  }
+
+  /**
+   * Send multiple emails in a batch
+   */
+  async sendBatch(emails: SendEmailOptions[]): Promise<SendEmailResponse[]> {
+    const payloads = emails.map((opts) => this.buildSendPayload(opts));
+    return this.request<SendEmailResponse[]>('POST', '/v1/emails/batch', { emails: payloads });
+  }
+
+  /**
+   * Get email status by ID
+   */
+  async getStatus(emailId: string): Promise<Record<string, unknown>> {
+    return this.request<Record<string, unknown>>('GET', `/v1/emails/${emailId}`);
+  }
+
+  /**
+   * Verify webhook signature
+   */
+  verifyWebhook(payload: string, signature: string, secret: string): boolean {
+    const crypto = require('crypto');
+    const expectedSignature = crypto
+      .createHmac('sha256', secret)
+      .update(payload)
+      .digest('hex');
+    
+    return crypto.timingSafeEqual(
+      Buffer.from(signature),
+      Buffer.from(expectedSignature)
+    );
+  }
+
+  /**
+   * Parse webhook payload
+   */
+  parseWebhook(body: string | Record<string, unknown>): WebhookPayload {
+    const data = typeof body === 'string' ? JSON.parse(body) : body;
+    return data as WebhookPayload;
+  }
+
+  /**
+   * Update mail configuration at runtime
+   */
+  updateMailConfig(config: Partial<MailConfig>): void {
+    Object.assign(this.mailConfig, config);
+  }
+
+  /**
+   * Get current mail configuration
+   */
+  getMailConfig(): MailConfig {
+    return { ...this.mailConfig };
+  }
+
+  private buildSendPayload(options: SendEmailOptions): Record<string, unknown> {
+    const from = options.from || this.mailConfig.defaultFrom;
+    if (!from) {
+      throw new MesaValidationError(
+        'Sender address is required. Set "from" in options or "defaultFrom" in mailConfig.',
+        'from'
+      );
+    }
+
+    const tracking = {
+      clicks: options.tracking?.clicks ?? this.mailConfig.trackClicks ?? true,
+      opens: options.tracking?.opens ?? this.mailConfig.trackOpens ?? true,
+    };
+
+    const tags = [
+      ...(this.mailConfig.defaultTags || []),
+      ...(options.tags || []),
+    ];
+
+    return {
+      from: this.normalizeAddress(from),
+      to: this.normalizeAddresses(options.to),
+      subject: options.subject,
+      html: options.html,
+      text: options.text,
+      cc: options.cc ? this.normalizeAddresses(options.cc) : undefined,
+      bcc: options.bcc ? this.normalizeAddresses(options.bcc) : undefined,
+      reply_to: this.normalizeAddress(options.replyTo || this.mailConfig.defaultReplyTo),
+      template_id: options.templateId,
+      template_data: options.templateData,
+      attachments: options.attachments,
+      headers: options.headers,
+      tags: tags.length > 0 ? tags : undefined,
+      metadata: options.metadata,
+      scheduled_at: options.scheduledAt,
+      tracking,
+      sandbox: this.mailConfig.sandbox,
+      ip_pool: this.mailConfig.ipPool,
+      ...this.getExtendedConfig(options),
+    };
+  }
+
+  private getExtendedConfig(options: SendEmailOptions): Record<string, unknown> {
+    const knownKeys = new Set([
+      'to', 'from', 'subject', 'html', 'text', 'cc', 'bcc', 'replyTo',
+      'templateId', 'templateData', 'attachments', 'headers', 'tags',
+      'metadata', 'scheduledAt', 'tracking',
+    ]);
+
+    const extended: Record<string, unknown> = {};
+    for (const [key, value] of Object.entries(options)) {
+      if (!knownKeys.has(key)) {
+        extended[key] = value;
+      }
+    }
+    return extended;
+  }
+
+  private normalizeAddress(addr: EmailAddress | string | undefined): EmailAddress | undefined {
+    if (!addr) return undefined;
+    if (typeof addr === 'string') {
+      return { email: addr };
+    }
+    return addr;
+  }
+
+  private normalizeAddresses(
+    addrs: EmailAddress | EmailAddress[] | string | string[]
+  ): EmailAddress[] {
+    const arr = Array.isArray(addrs) ? addrs : [addrs];
+    return arr.map((a) => (typeof a === 'string' ? { email: a } : a));
+  }
+
+  private async request<T>(
+    method: string,
+    path: string,
+    body?: unknown
+  ): Promise<T> {
+    const url = `${this.baseUrl}${path}`;
+    let lastError: Error | null = null;
+
+    for (let attempt = 0; attempt <= this.retries; attempt++) {
+      try {
+        const controller = new AbortController();
+        const timeoutId = setTimeout(() => controller.abort(), this.timeout);
+
+        const response = await fetch(url, {
+          method,
+          headers: {
+            'Content-Type': 'application/json',
+            'Authorization': `Bearer ${this.apiKey}`,
+            'User-Agent': '@armco/mesa-sdk/1.0.0',
+          },
+          body: body ? JSON.stringify(body) : undefined,
+          signal: controller.signal,
+        });
+
+        clearTimeout(timeoutId);
+
+        if (!response.ok) {
+          const errorData = await response.json().catch(() => ({}));
+          throw new MesaAPIError(
+            errorData.message || `Request failed with status ${response.status}`,
+            response.status,
+            errorData.code || 'API_ERROR',
+            errorData.details
+          );
+        }
+
+        return (await response.json()) as T;
+      } catch (error) {
+        lastError = error as Error;
+
+        if (error instanceof MesaAPIError && error.statusCode < 500) {
+          throw error;
+        }
+
+        if (attempt < this.retries) {
+          await this.sleep(Math.pow(2, attempt) * 100);
+        }
+      }
+    }
+
+    throw lastError;
+  }
+
+  private sleep(ms: number): Promise<void> {
+    return new Promise((resolve) => setTimeout(resolve, ms));
+  }
+}
diff --git a/src/errors.ts b/src/errors.ts
new file mode 100644
index 0000000..dbcc2ff
--- /dev/null
+++ b/src/errors.ts
@@ -0,0 +1,57 @@
+/**
+ * Base error class for Mesa SDK
+ */
+export class MesaError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = 'MesaError';
+    Object.setPrototypeOf(this, MesaError.prototype);
+  }
+}
+
+/**
+ * API error with status code and response details
+ */
+export class MesaAPIError extends MesaError {
+  public readonly statusCode: number;
+  public readonly code: string;
+  public readonly details?: Record<string, unknown>;
+
+  constructor(
+    message: string,
+    statusCode: number,
+    code: string,
+    details?: Record<string, unknown>
+  ) {
+    super(message);
+    this.name = 'MesaAPIError';
+    this.statusCode = statusCode;
+    this.code = code;
+    this.details = details;
+    Object.setPrototypeOf(this, MesaAPIError.prototype);
+  }
+
+  toJSON() {
+    return {
+      name: this.name,
+      message: this.message,
+      statusCode: this.statusCode,
+      code: this.code,
+      details: this.details,
+    };
+  }
+}
+
+/**
+ * Validation error for invalid input
+ */
+export class MesaValidationError extends MesaError {
+  public readonly field: string;
+
+  constructor(message: string, field: string) {
+    super(message);
+    this.name = 'MesaValidationError';
+    this.field = field;
+    Object.setPrototypeOf(this, MesaValidationError.prototype);
+  }
+}
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..748309b
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,12 @@
+export { MesaClient } from './client';
+export { MesaError, MesaAPIError, MesaValidationError } from './errors';
+export type {
+  MesaConfig,
+  MailConfig,
+  SendEmailOptions,
+  SendEmailResponse,
+  EmailAddress,
+  Attachment,
+  WebhookEvent,
+  WebhookPayload,
+} from './types';
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 0000000..3cda8ae
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,192 @@
+/**
+ * Mesa SDK Configuration
+ */
+export interface MesaConfig {
+  /** API Key for authentication */
+  apiKey: string;
+  
+  /** Base URL of Mesa/Sandesh API (default: https://api.sandesh.armco.dev) */
+  baseUrl?: string;
+  
+  /** Request timeout in milliseconds (default: 30000) */
+  timeout?: number;
+  
+  /** Number of retry attempts for failed requests (default: 3) */
+  retries?: number;
+  
+  /**
+   * Mail configuration object - flexible JSON config for email settings.
+   * New settings added to Sandesh can be passed here without SDK updates.
+   */
+  mailConfig?: MailConfig;
+}
+
+/**
+ * Flexible mail configuration - supports any key-value pairs.
+ * Core fields are typed, additional fields are allowed for extensibility.
+ */
+export interface MailConfig {
+  /** Default sender email address */
+  defaultFrom?: EmailAddress;
+  
+  /** Default reply-to address */
+  defaultReplyTo?: EmailAddress;
+  
+  /** Enable click tracking (default: true) */
+  trackClicks?: boolean;
+  
+  /** Enable open tracking (default: true) */
+  trackOpens?: boolean;
+  
+  /** Custom tracking domain */
+  trackingDomain?: string;
+  
+  /** Default tags to apply to all emails */
+  defaultTags?: string[];
+  
+  /** Sandbox mode - emails are logged but not sent */
+  sandbox?: boolean;
+  
+  /** IP pool name for dedicated IPs */
+  ipPool?: string;
+  
+  /** Send time optimization */
+  sendTimeOptimization?: boolean;
+  
+  /** Allow any additional config fields for forward compatibility */
+  [key: string]: unknown;
+}
+
+/**
+ * Email address with optional display name
+ */
+export interface EmailAddress {
+  email: string;
+  name?: string;
+}
+
+/**
+ * Email attachment
+ */
+export interface Attachment {
+  /** Filename */
+  filename: string;
+  
+  /** Base64 encoded content */
+  content: string;
+  
+  /** MIME type (e.g., 'application/pdf') */
+  contentType?: string;
+  
+  /** Content-ID for inline attachments */
+  cid?: string;
+}
+
+/**
+ * Options for sending an email
+ */
+export interface SendEmailOptions {
+  /** Recipient(s) */
+  to: EmailAddress | EmailAddress[] | string | string[];
+  
+  /** Sender (overrides mailConfig.defaultFrom) */
+  from?: EmailAddress | string;
+  
+  /** Email subject */
+  subject: string;
+  
+  /** HTML body */
+  html?: string;
+  
+  /** Plain text body */
+  text?: string;
+  
+  /** CC recipients */
+  cc?: EmailAddress | EmailAddress[] | string | string[];
+  
+  /** BCC recipients */
+  bcc?: EmailAddress | EmailAddress[] | string | string[];
+  
+  /** Reply-to address */
+  replyTo?: EmailAddress | string;
+  
+  /** Template ID to use */
+  templateId?: string;
+  
+  /** Template variables */
+  templateData?: Record<string, unknown>;
+  
+  /** File attachments */
+  attachments?: Attachment[];
+  
+  /** Custom headers */
+  headers?: Record<string, string>;
+  
+  /** Tags for categorization */
+  tags?: string[];
+  
+  /** Custom metadata */
+  metadata?: Record<string, string>;
+  
+  /** Schedule send time (ISO 8601) */
+  scheduledAt?: string;
+  
+  /** Override tracking settings for this email */
+  tracking?: {
+    clicks?: boolean;
+    opens?: boolean;
+  };
+  
+  /** Allow any additional options for forward compatibility */
+  [key: string]: unknown;
+}
+
+/**
+ * Response from sending an email
+ */
+export interface SendEmailResponse {
+  /** Unique message ID */
+  id: string;
+  
+  /** Status of the send operation */
+  status: 'queued' | 'sent' | 'scheduled';
+  
+  /** Timestamp */
+  timestamp: string;
+  
+  /** Additional response data */
+  [key: string]: unknown;
+}
+
+/**
+ * Webhook event types
+ */
+export type WebhookEvent =
+  | 'email.sent'
+  | 'email.delivered'
+  | 'email.bounced'
+  | 'email.complained'
+  | 'email.opened'
+  | 'email.clicked'
+  | 'email.unsubscribed'
+  | 'inbound.received';
+
+/**
+ * Webhook payload
+ */
+export interface WebhookPayload {
+  /** Event type */
+  event: WebhookEvent;
+  
+  /** Event timestamp */
+  timestamp: string;
+  
+  /** Message ID */
+  messageId: string;
+  
+  /** Recipient email */
+  recipient?: string;
+  
+  /** Event-specific data */
+  data: Record<string, unknown>;
+}
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..914d14d
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "lib": ["ES2020", "DOM"],
+    "types": ["node"],
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "noImplicitAny": true,
+    "strictNullChecks": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}