SMS API Documentation & Integration Guide

The Tossable Digits SMS API is a RESTful HTTP API that works with any programming language capable of making HTTP requests and parsing JSON responses. We provide official code libraries and working examples for popular languages including Python, PHP, Node.js, Ruby, Java, and C#. Even if your preferred language isn't in our example library, the straightforward REST architecture means you can integrate using standard HTTP client libraries. Our documentation includes cURL examples that translate easily to any development environment.

API authentication uses secure API keys that you generate through your developer portal dashboard. Include your API key in the request header of each API call using the standard Authorization header format. For enhanced security, we support two-factor authentication on your account and recommend IP whitelisting for production environments. API keys can be rotated at any time, and you can generate separate keys for development, staging, and production environments to maintain security isolation across your deployment pipeline.

Rate limits vary based on your account type and messaging volume requirements. Standard accounts support hundreds of messages per minute, which suits most business applications. For high-volume use cases requiring thousands of messages per minute—such as emergency alerts, marketing campaigns, or authentication systems—contact our technical team to discuss dedicated infrastructure and custom rate limit increases. We'll work with you to ensure your messaging throughput meets your application's needs without service degradation or delivery delays.

Yes, incoming SMS messages are delivered to your application in real-time via webhooks. Configure your webhook endpoint URL in the dashboard, and we'll POST incoming message data to that endpoint immediately upon receipt. The webhook payload includes sender number, message content, timestamp, and the receiving virtual number. Webhooks use HTTPS for security and include signature verification so you can authenticate that requests genuinely originated from Tossable Digits. Webhook retry logic handles temporary endpoint unavailability automatically.

The API supports programmatic provisioning of local numbers from 500+ US and Canadian cities, toll-free numbers (800, 888, 877, 866, 855 prefixes), and international numbers from 84 countries. You can search available number inventory by area code, city, or country code, then activate numbers instantly via API call. Toll-free numbers support business SMS messaging, while local numbers are restricted to person-to-person messaging per carrier regulations. International number availability and activation timeframes vary by country—some activate instantly while others require address registration.

Each SMS sent through the API returns a unique message ID that you can use to track delivery status. Query the message status endpoint to retrieve real-time delivery information including sent, delivered, failed, or undelivered states. Delivery receipt webhooks provide automatic notification when message status changes. The API returns detailed error codes and messages for failed sends, including invalid numbers, carrier rejections, or content filtering issues, enabling your application to implement appropriate retry logic or user notifications based on specific failure reasons.

Yes, we provide a full-featured sandbox environment that mirrors production API behavior without affecting live phone numbers or incurring messaging charges. The sandbox allows you to test all API endpoints, webhook configurations, and error handling scenarios in a risk-free environment. Sandbox numbers receive and send test messages that don't reach real phones. Use the sandbox to validate your integration thoroughly before deploying to production, ensuring your application handles success and failure scenarios correctly.

Our technical support team includes experienced integration specialists who assist with implementation questions, troubleshooting, and optimization recommendations. Access support through email, phone, or our developer portal ticketing system. We provide architecture review for complex integrations, help debug webhook issues, and offer guidance on best practices for high-volume messaging systems. Documentation includes extensive code examples, common implementation patterns, and troubleshooting guides. For enterprise customers, we offer dedicated technical account management and priority support response.