Non-Functional Requirements
Purpose of this document
This document provides business, technical (including configuration), and implementation details for specific features within the ES Loyalty feature set. This document specifically addresses a subset of functionality centred on non-functional requirements.
POS response time
Response time of less than 750ms from time to first byte (TTFB), excluding the routine maintenance window, based on a performance load that does not exceed 150 transactions per second.
TTFB measures the duration from the moment a user or client makes an HTTP request to the moment the first byte of the page is received by the client's browser. This time is made up of:
- The socket connection time
- The time taken to send the HTTP request
- The time taken to receive the first byte of the page
In general, a TTFB of under 800ms is considered optimal.
The 750ms response time must be maintained under loads of up to 150 transactions per second.
Number of concurrent active offers
ES Loyalty must be able to scale to support numerous simultaneous offers in market across different campaigns, with varying aspects such as targeting and rewards design. The robustness of this capability is reflected in the richness of the offerings and the ability to precisely target different groups of users based on many combinations of criteria.