--- title: Prompt Caching with the OpenAI API: A Full Hands-On... description: Prompt caching in the OpenAI API allows reusing repeated parts of LLM inputs (like system prompts) to reduce latency by up to 80% and costs by up to 90%. For... canonical: https://daily.dev/posts/prompt-caching-with-the-openai-api-a-full-hands-on-python-tutorial-2v9ujmvm5 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Prompt Caching with the OpenAI API: A Full Hands-On Python tutorial | daily.dev og:description: Prompt caching in the OpenAI API allows reusing repeated parts of LLM inputs (like system prompts) to reduce latency by up to 80% and costs by up to 90%. For... og:url: https://daily.dev/posts/prompt-caching-with-the-openai-api-a-full-hands-on-python-tutorial-2v9ujmvm5 og:image: https://api.daily.dev/og/posts/2V9UJmvM5.png og:image:alt: Prompt Caching with the OpenAI API: A Full Hands-On Python tutorial og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Prompt Caching with the OpenAI API: A Full Hands-On Python tutorial **[Towards Data Science](https://daily.dev/sources/tds)** · 9 min read · 2 upvotes · 0 comments ## Summary Prompt caching in the OpenAI API allows reusing repeated parts of LLM inputs (like system prompts) to reduce latency by up to 80% and costs by up to 90%. For caching to activate, the repeated prefix must appear at the start of the prompt and exceed 1,024 tokens. A hands-on Python example demonstrates making two requests with the same long prefix, showing measurable latency improvements on the second call. Key pitfalls include prefixes below the token threshold, inserting dynamic content before the prefix (which breaks caching), and misunderstanding that only the pre-fill phase is cached — not decoding. The `prompt_cache_key` parameter exists in the API spec but is not yet exposed in the Python SDK. Prompt caching is less useful for highly dynamic prompts, one-off requests, or real-time personalized systems. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Prompt Caching Explained](https://daily.dev/posts/prompt-caching-explained-mhomvre8o) · DigitalOcean Community · 2 upvotes · 0 comments - [Why Care About Prompt Caching in LLMs?](https://daily.dev/posts/why-care-about-prompt-caching-in-llms--xsybxgzta) · Towards Data Science · 1 upvotes · 0 comments - [Prompt Caching for Anthropic and OpenAI Models: Building Cost-Efficient AI Systems](https://daily.dev/posts/prompt-caching-for-anthropic-and-openai-models-building-cost-efficient-ai-systems-mjzh92xkq) · DigitalOcean · 2 upvotes · 0 comments - [Prompt Caching Techniques](https://daily.dev/posts/prompt-caching-techniques-rlnexmcrg) · PromptLayer Blog · 1 upvotes · 0 comments --- Tags: [#python](https://daily.dev/tags/python), [#llm](https://daily.dev/tags/llm), [#finops](https://daily.dev/tags/finops) [View this post on daily.dev](https://daily.dev/posts/prompt-caching-with-the-openai-api-a-full-hands-on-python-tutorial-2v9ujmvm5) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Prompt Caching with the OpenAI API: A Full Hands-On Python tutorial","url":"https://daily.dev/posts/prompt-caching-with-the-openai-api-a-full-hands-on-python-tutorial-2v9ujmvm5","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/prompt-caching-with-the-openai-api-a-full-hands-on-python-tutorial-2v9ujmvm5"},"datePublished":"2026-03-22T15:07:36.112Z","dateModified":"2026-03-22T15:08:05.751Z","description":"Prompt caching in the OpenAI API allows reusing repeated parts of LLM inputs (like system prompts) to reduce latency by up to 80% and costs by up to 90%. 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