Performance optimization
Applications that depend on external APIs often inherit their latency. Every outbound call adds round-trip time, and the same responses are fetched again and again. Writing caching and traffic-management code by hand is easy to get wrong, and it rarely delivers direct business value.
HARP sits between your application and the remote APIs it calls, so you can address this at the proxy level without changing application code: it caches responses, distributes traffic across upstream servers, and lets you shape caching through rules.
Understanding the use case
When an application relies on third-party services, those dependencies introduce delays that accumulate under load. Repeatedly fetching identical data wastes time and bandwidth, and a single overloaded upstream can slow every request that depends on it. Building caching and traffic distribution into the application means more code to write, test, and maintain; moving it to HARP keeps your codebase focused on features while the proxy handles the network-level work.
How HARP helps
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Cache repeated responses: HARP's RFC-9111 compliant cache serves identical requests locally instead of hitting the remote API every time, cutting both response times and outbound traffic. For compliant APIs it works with no setup.
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Cache APIs that do not cooperate: many APIs omit usable cache-control headers. For those, the rules engine lets you set caching behaviour explicitly, based on what you know about how that data changes.
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Spread load across upstreams: instead of a single endpoint, define a pool of remote URLs. HARP distributes requests across them in round-robin, avoiding single-server saturation and keeping your application responsive under heavier load.
All of this is configuration rather than code, so performance tuning stays separate from your application and out of your team's maintenance burden.
Benefits
- Faster responses, by avoiding repeated round trips to slow upstreams, including during traffic peaks.
- Lower load on upstream APIs, from fewer redundant calls and traffic spread across several servers.
- Less code to maintain, because caching and distribution live in the proxy, not your services.