API Overview

Gamma offer a wide range of APIs across our Voice, Mobile and Data products. All our APIs are HTTP based. Some of our older style APIs do not conform to this documentation, please refer to the individual API documentation for full details.

The documentation on this page applies to all our newer APIs. This page covers features that apply to all APIs. Please also refer to our REST Overview documentation for REST-specific features.


Many APIs use specific technical terms. Please see the glossary for terms and their definitions.

Rate Limits

Some requests may be subject to rate limits. These limits define how many requests may be sent within a given period.

You can determine how many requests you may send and how many you have remaining by looking at the rate limit headers which may be present in a response.

Header Description
X-RateLimit-Limit The maximum number of requests you're permitted to make within the client's rate limit window
X-RateLimit-Interval The duration of the client's rate limit window in UTC epoch seconds
X-RateLimit-Remaining The number of requests remaining in the current rate limit window
X-RateLimit-Reset The time at which the current rate limit window resets in UTC epoch seconds

Data Formats

Common data is sent in a consistent format.

Data Type Format Example
Email Address RFC5322 email@email.com
Post Code ILR Specification AB2 1AB
Date and Time ISO 8601 2018-10-17T15:53:00
CLIs and MSISDNs E.164 +441514960453  +447700900859  +14155550169
URI RFC3986 http://www.gamma.co.uk/example.txt
IPv4 RFC791
IPv6 RFC2460 2001:0db8:85a3:0000:0000:8a2e:0370:7334