--- title: Intercepting and Decoding Claude Code API Calls Using... description: A hands-on walkthrough showing how to intercept and decode Claude Code's live API calls using mitmproxy. By routing Claude Code's HTTPS traffic through a... canonical: https://daily.dev/posts/intercepting-and-decoding-claude-code-api-calls-using-mitm-proxy-mhcghpfxk twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Intercepting and Decoding Claude Code API Calls Using MITM Proxy | daily.dev og:description: A hands-on walkthrough showing how to intercept and decode Claude Code's live API calls using mitmproxy. By routing Claude Code's HTTPS traffic through a... og:url: https://daily.dev/posts/intercepting-and-decoding-claude-code-api-calls-using-mitm-proxy-mhcghpfxk og:image: https://api.daily.dev/og/posts/mHCgHPFXK.png og:image:alt: Intercepting and Decoding Claude Code API Calls Using MITM Proxy 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. # Intercepting and Decoding Claude Code API Calls Using MITM Proxy **[C\# Corner](https://daily.dev/sources/csharpcorner)** · 7 min read · 0 upvotes · 0 comments ## Summary A hands-on walkthrough showing how to intercept and decode Claude Code's live API calls using mitmproxy. By routing Claude Code's HTTPS traffic through a man-in-the-middle proxy, you can inspect the full 80 KB payload sent to Anthropic on every request. The payload breaks down into four sections: system prompt, tool definitions, CLAUDE.md content, and conversation history. Key findings include that CLAUDE.md is injected verbatim into every request (a compliance concern), the agent operates as a while loop that grows the conversation history cumulatively, and prompt caching keeps costs from scaling quadratically. The post also covers using JSONL session logs with tools like claude-replay and cclogviewer for auditing and debugging. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Using Proxies to Hide Secrets from Claude Code](https://daily.dev/posts/using-proxies-to-hide-secrets-from-claude-code-lji9p9dap) · Hacker News · 0 upvotes · 0 comments --- Tags: [#anthropic](https://daily.dev/tags/anthropic), [#claude-code](https://daily.dev/tags/claude-code) [View this post on daily.dev](https://daily.dev/posts/intercepting-and-decoding-claude-code-api-calls-using-mitm-proxy-mhcghpfxk) ```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":"Intercepting and Decoding Claude Code API Calls Using MITM Proxy","url":"https://daily.dev/posts/intercepting-and-decoding-claude-code-api-calls-using-mitm-proxy-mhcghpfxk","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/intercepting-and-decoding-claude-code-api-calls-using-mitm-proxy-mhcghpfxk"},"datePublished":"2026-04-26T08:09:10.124Z","dateModified":"2026-04-26T08:09:33.333Z","description":"A hands-on walkthrough showing how to intercept and decode Claude Code's live API calls using mitmproxy. 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