Hey HN, I'm Somesh, a 17-year-old builder from India.

While building multi-turn AI apps, I kept running into two problems with existing LLM gateways:

Cloud proxy gateways force you to route every prompt through a third-party server (adding 80–200ms of network latency and creating a PII compliance nightmare).

Most teams silently lose 30–50% of their OpenAI/Anthropic bill to broken 1,024-token prompt cache prefixes (putting dynamic timestamps/UUIDs at token 0), stuck Period-1/Period-2 agent retry loops, and re-sending massive tool/vision payloads across turns.

So I built TokenVault ( https://www.tockenvault.com ) using a 5-language specialized stack:

Rust -> WebAssembly ( Wasm ) binary kernel in the browser for zero-GC 64-bit FNV-1a 256-token Radix block fingerprinting, Luhn mod-10 card checks, and Shannon entropy secret scanning.

Native single-file Python SDK ( token_vault.py hooking httpx ) and Node/Edge SDK ( token-vault.js hooking globalThis.fetch ) bounded strictly to a 512 KB in-memory ring…