Ktor Middleware Technique Cuts Mobile API Payload Size Based on Network Speed

A software engineering tutorial published on DEV Community outlines a method for building a three-layer Ktor middleware pipeline that dynamically reduces JSON API response sizes based on client-reported bandwidth. The approach uses a custom HTTP header through which mobile clients self-report their estimated connection speed, derived from prior response timing data. A custom Kotlin annotation assigns priority tiers to data model fields, allowing the server to drop non-critical fields, collapse nested objects, or strip embedded assets when bandwidth is limited. Internal benchmarking cited in the article found that payload size accounts for 38–52% of perceived response time on cellular connections below 2 Mbps, a gap the author argues HTTP/2 and gzip alone cannot close. The technique is designed to leave the API contract unchanged, requiring no modifications to existing clients.