The API Optimization Everyone Overlooks: How Prompt Caching Cuts Costs by 90%

Most developers don't realize that prompt caching in mainstream APIs can reduce token costs by up to 90%, yet the feature remains underutilized. By restructuring prompts to place static content—system messages, context, and tools—before variable user inputs, developers can dramatically improve cache hit rates and lower API expenses. For indie developers and startups operating on thin margins, mastering this kind of API optimization is increasingly the difference between sustainable growth and unsustainable cash burn.