Bandwidth

The REST API covers voice (call initiation, call control via BXML, conference management), messaging (SMS/MMS send and receive, campaign management for 10DLC), phone numbers (provisioning and porting), and emergency services (E911 address provisioning). Agents can initiate outbound calls with dynamic call flow logic defined in BXML (Bandwidth XML), send SMS messages at scale with campaign registration compliance, and manage phone number inventory.

Reliability is carrier-grade for direct network access. Bandwidth's own network infrastructure provides the reliability guarantees required for E911 and enterprise telephony applications where voice quality and availability directly affect safety and business operations. Teams deploying voice applications on Bandwidth should implement appropriate redundancy for the application layer.

Bandwidth is an enterprise communications platform providing direct access to carrier-grade voice and messaging infrastructure through a REST API. Unlike aggregators that resell carrier capacity, Bandwidth operates its own nationwide network — providing direct carrier connectivity for applications requiring high-reliability telephony, E911 emergency services, and STIR/SHAKEN call authentication compliance. For agents managing enterprise voice and messaging workflows, Bandwidth's API covers voice calls, SMS/MMS, phone number management, and emergency services.

Authentication uses HTTP Basic Auth with API credentials (account ID and API token/secret). The credential model is straightforward for server-side agent integration. Teams should implement HTTPS-only communication and protect API credentials with appropriate secret management given that Bandwidth credentials authorize telephony charges.

Documentation is comprehensive and covers the voice, messaging, and number management APIs with code examples. The BXML documentation — covering Bandwidth's XML-based call flow control — is the key reference for voice application development. Teams evaluating Bandwidth versus Twilio or Vonage for enterprise telephony should compare the direct carrier access advantage against Twilio's ecosystem breadth and developer experience.