Telnyx RCS customers can now make smarter routing decisions by verifying whether a destination number is RCS-capable before sending. The new RCS Capabilities Check API enables developers to query a single phone number or a list of numbers and determine if both the device and carrier support RCS.
The RCS Capabilities Check API offers both single-number and bulk lookup options. With the single-number endpoint, developers provide an agent_id and a phone number in the URL path to receive a JSON response detailing the device and carrier’s RCS support. The bulk endpoint accepts up to 100 phone numbers in a single POST request and returns an array of results, one for each number queried.
Each response includes whether the device is RCS-enabled, whether the carrier supports RCS, and which RCS features are available, such as support for rich cards, media attachments, and suggested action buttons. If a number does not support RCS, the features field will be empty or null, signaling the need to fall back to SMS or MMS.
There are some known limitations. Carriers and devices may not always report full capability data, even if RCS is technically supported. Additionally, Google’s RCS platform (RBM) can exhibit inconsistent behavior. For instance, if a user uninstalls the RCS app or their device temporarily goes offline, the API may not recognize the device as RCS-enabled, even though it typically is.
Smarter RCS routing: By checking capabilities first, your application can automatically use RCS for numbers that support it and SMS/MMS for others. This eliminates guesswork and ensures you use the richest channel available. In the past, routing often relied on trial-and-error, which led to unnecessary fallbacks and reduced reliability. With this update, routing decisions can be made proactively, improving efficiency and delivery rates.
Reduced fallback traffic: Because non-RCS numbers are identified in advance, you avoid sending RCS attempts that would fail and require an SMS/MMS fallback. This cuts down on unnecessary message retries and helps lower operational costs.
Improved messaging reliability: Sending messages in the correct format on the first attempt increases overall delivery success.
Knowing RCS support in advance helps you focus rich-media campaigns on receptive audiences, improving both delivery efficiency and ROI. By delivering RCS messages to supported devices and defaulting to SMS or MMS for others, you ensure a seamless experience and maximize engagement across your audience.
Telnyx customers can start using RCS capability checks by following our quickstart guide or by incorporating the capability check endpoint into their existing RCS messaging workflows using the API reference.
