> ## Documentation Index > Fetch the complete documentation index at: https://docs.xerobi.com/llms.txt > Use this file to discover all available pages before exploring further. # Send Bulk SMS > Send SMS to multiple recipients in a single API call. Ideal for campaigns and notifications to large audiences. **Features:** - Send to up to 10,000 recipients per request - Asynchronous processing - Job status tracking - Automatic rate limiting and queuing - Per-recipient personalization support **Best Practices:** - Break very large lists into batches of 10,000 - Use off-peak hours for large campaigns - Monitor job status via webhooks - Test with small batches first ## OpenAPI ````yaml POST /bulk openapi: 3.1.0 info: title: Xerobi SMS Gateway API version: '2026-01-01' description: >- A modern, developer-friendly SMS Gateway API supporting transactional, OTP, promotional and bulk messaging. ## Overview The Xerobi SMS Gateway API enables you to send SMS messages programmatically with support for: - **Transactional SMS**: Account notifications, confirmations, alerts - **OTP Messages**: One-time passwords with optimized delivery routes - **Promotional SMS**: Marketing campaigns and announcements - **Bulk Messaging**: Send to thousands of recipients efficiently - **Templates**: Reusable message templates with variable substitution - **Webhooks**: Real-time delivery status notifications ## Authentication Authenticate using your API key as a Bearer token: ```bash curl -H "Authorization: Bearer sk_live_xxxxx" \ -H "Xerobi-Version: 2026-01-01" \ https://api.hixbe.com/sms/messages ``` **API Key Types:** - `sk_live_*` - Production keys for live messaging - `sk_test_*` - Test keys for development (no actual SMS sent) Get your API keys from the [Xerobi Dashboard](https://dashboard.hixbe.com/api-keys). ## Rate Limits - **Standard accounts**: 100 requests/minute - **Business accounts**: 1,000 requests/minute - **Enterprise accounts**: Custom limits Rate limit headers are included in all responses: - `X-RateLimit-Limit`: Maximum requests per window - `X-RateLimit-Remaining`: Requests remaining - `X-RateLimit-Reset`: Unix timestamp when limit resets ## Message Routes Different routes optimize for delivery speed, reliability, and cost: | Route | Use Case | Delivery Speed | Cost | |-------|----------|----------------|------| | **otp** | One-time passwords | < 5 seconds | Premium | | **transactional** | Notifications, alerts | < 30 seconds | Standard | | **promotional** | Marketing messages | < 2 minutes | Economy | ## Phone Number Format Phone numbers must be in international format without + or spaces: - ✅ Correct: `8801712345678` (Bangladesh) - ✅ Correct: `14155551234` (USA) - ❌ Incorrect: `+880 171 234 5678` - ❌ Incorrect: `01712345678` ## Idempotency Include `Idempotency-Key` header to safely retry requests: ```bash curl -H "Idempotency-Key: unique-key-123" \ -H "Authorization: Bearer sk_live_xxxxx" \ ... ``` ## Webhooks Receive real-time delivery updates via webhooks. Events include: - `message.queued` - Message accepted and queued - `message.sent` - Message sent to carrier - `message.delivered` - Successfully delivered - `message.failed` - Delivery failed ## Support Need help? Contact us: - Email: support@xerobi.com - Documentation: https://developer.hixbe.com - Status: https://status.hixbe.com contact: name: Xerobi Developer Support url: https://developer.hixbe.com email: support@xerobi.com termsOfService: https://hixbe.com/terms license: name: Commercial url: https://hixbe.com/license servers: - url: https://api.hixbe.com/sms description: Production Server - url: https://api-sandbox.hixbe.com/sms description: Sandbox Server (test mode) security: - bearerAuth: [] tags: - name: Messages description: Send and track individual SMS messages - name: Bulk description: CSV and list-based bulk sending for campaigns - name: Senders description: Manage sender IDs and registration - name: Templates description: Create and manage message templates with variables - name: Reports description: Delivery statistics and usage analytics - name: Account description: Balance, usage limits and account profile - name: Webhooks description: Configure delivery report callbacks paths: /bulk: post: tags: - Bulk summary: Send bulk SMS description: >- Send SMS to multiple recipients in a single API call. Ideal for campaigns and notifications to large audiences. **Features:** - Send to up to 10,000 recipients per request - Asynchronous processing - Job status tracking - Automatic rate limiting and queuing - Per-recipient personalization support **Best Practices:** - Break very large lists into batches of 10,000 - Use off-peak hours for large campaigns - Monitor job status via webhooks - Test with small batches first operationId: sendBulkSMS parameters: - $ref: '#/components/parameters/Xerobi-Version' requestBody: required: true content: application/json: schema: type: object properties: recipients: type: array description: List of recipient phone numbers (max 10,000) items: type: string minItems: 1 maxItems: 10000 example: - '8801712345678' - '8801987654321' message: type: string description: Message content (same for all recipients) example: Flash Sale! 50% off everything today only. Shop now! minLength: 1 maxLength: 1000 from: type: string description: Sender ID (must be approved) example: HIXBE maxLength: 11 route: type: string enum: - transactional - promotional default: promotional description: Message route (OTP not available for bulk) example: promotional schedule_at: type: string format: date-time nullable: true description: Schedule bulk send for future time example: '2026-01-16T09:00:00Z' required: - recipients - message example: recipients: - '8801712345678' - '8801987654321' - '8801555555555' message: Flash Sale! 50% off everything today only. Shop now at hixbe.com from: HIXBE route: promotional responses: '202': description: Bulk job accepted and processing content: application/json: schema: $ref: '#/components/schemas/BulkJob' example: id: job_bulk_001 status: processing total: 3 queued: 3 sent: 0 delivered: 0 failed: 0 estimated_cost: 1.5 created_at: '2026-01-15T10:00:00Z' completed_at: null '400': $ref: '#/components/responses/ValidationError' '401': $ref: '#/components/responses/Unauthorized' '402': $ref: '#/components/responses/InsufficientBalance' '429': $ref: '#/components/responses/RateLimitError' components: parameters: Xerobi-Version: name: Xerobi-Version in: header description: >- API version in YYYY-MM-DD format. Using the latest version ensures access to newest features. required: true schema: type: string default: '2026-01-01' pattern: ^\d{4}-\d{2}-\d{2}$ example: '2026-01-01' schemas: BulkJob: type: object description: Bulk messaging job status and statistics properties: id: type: string description: Unique job identifier example: job_bulk_001 status: type: string enum: - processing - completed - failed - cancelled description: Job processing status example: processing total: type: integer description: Total number of recipients example: 5000 minimum: 1 queued: type: integer description: Messages queued for delivery example: 4850 sent: type: integer description: Messages sent to carrier example: 150 delivered: type: integer description: Successfully delivered messages example: 120 failed: type: integer description: Failed deliveries example: 5 estimated_cost: type: number description: Estimated total cost example: 250 created_at: type: string format: date-time description: Job creation timestamp example: '2026-01-15T10:00:00Z' completed_at: type: string format: date-time nullable: true description: Job completion timestamp example: null required: - id - status - total - queued Error: type: object description: Standard error response with detailed information properties: error: type: object properties: type: type: string description: Error category for programmatic handling example: validation_error code: type: string description: Specific error code example: invalid_phone_number message: type: string description: Human-readable error message example: >- Phone number must be in international format without spaces or special characters param: type: string nullable: true description: Parameter that caused the error example: to request_id: type: string description: Unique request identifier for support and debugging example: req_abc123xyz doc_url: type: string description: Link to relevant documentation example: https://developer.hixbe.com/errors/invalid-phone-number required: - type - code - message - request_id required: - error responses: ValidationError: description: Request validation failed content: application/json: schema: $ref: '#/components/schemas/Error' example: error: type: validation_error code: invalid_phone_number message: >- Phone number must be in international format (e.g., 8801712345678) param: to request_id: req_def456 doc_url: https://developer.hixbe.com/phone-format Unauthorized: description: Authentication failed - invalid or missing API key content: application/json: schema: $ref: '#/components/schemas/Error' example: error: type: authentication_error code: invalid_api_key message: >- Invalid API key provided. Check your API key at https://dashboard.hixbe.com/api-keys request_id: req_abc123 InsufficientBalance: description: Insufficient account balance content: application/json: schema: $ref: '#/components/schemas/Error' example: error: type: payment_error code: insufficient_balance message: >- Insufficient balance. Current balance: 5.20 BDT. Required: 25.00 BDT. Please recharge your account. request_id: req_ghi789 doc_url: https://dashboard.hixbe.com/billing/recharge RateLimitError: description: Rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/Error' example: error: type: rate_limit_error code: rate_limit_exceeded message: Too many requests. Please retry after 60 seconds. request_id: req_xyz789 headers: X-RateLimit-Limit: schema: type: integer description: Maximum requests per window example: 100 X-RateLimit-Remaining: schema: type: integer description: Requests remaining example: 0 X-RateLimit-Reset: schema: type: integer description: Unix timestamp when limit resets example: 1705324800 Retry-After: schema: type: integer description: Seconds to wait before retry example: 60 securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: APIKEY description: >- Use your API key as a Bearer token. Format: `Authorization: Bearer sk_live_xxxxx` ```` ## Related topics - [SMS API FAQ](https://docs.xerobi.com/faq-guides/sms-api-faq.md) - [Send SMS](https://docs.xerobi.com/sms-api/endpoint/send-sms.md) - [Xerobi SMS Gateway API Introduction](https://docs.xerobi.com/sms-api/introduction.md) - [Send using template](https://docs.xerobi.com/sms-api/endpoint/send-template.md) - [Get bulk job status](https://docs.xerobi.com/sms-api/endpoint/get-bulk-job.md) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.