Design notes
from jpzip
Cloudflare Pages design, MCP servers, shipping 8 SDKs with Claude Code — the architecture and numbers behind jpzip, written down.
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How Claude Code shipped 8 language SDKs in 6 hours
How I shipped Go / TypeScript / Python / Rust / Ruby / Dart / PHP / Swift SDKs for jpzip in 6 hours using Claude Code — spec-first design, Go as the reference implementation, translation-not-transpilation prompting, and per-language gotchas.
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I wrote an MCP server so Claude can natively look up Japanese postcodes
A tiny stateless MCP server that lets Claude resolve Japanese postcodes — tool design, cache lifetimes, cross-script (kanji/katakana/romaji) search.
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How I serve 120,677 Japanese postcodes from Cloudflare Pages (no Worker, no R2)
The data-delivery design behind jpzip — shard layout, ETL pipeline, and why I deliberately use no Worker, no R2, no KV.
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I built a postcode-data micro-SaaS on Cloudflare Pages' free tier (and it costs me $0)
The story behind jpzip, a one-person side project, and why it stays free forever — not by luck, but by design. 120,677 Japanese postcodes served from Cloudflare Pages alone.