What is Lexi?

Lexi is an AI API proxy that sits between your application and AI providers like OpenAI, Anthropic, and Google. It uses a proprietary engine called STONE (Semantic Token Optimization and Natural Encoding) to restructure conversation context before each API call, reducing the number of tokens sent while preserving meaning. This results in significant cost savings without changing your code.

How to use Lexi?

Create a free account on lexisaas.com and get an API key. Change the base URL in your existing OpenAI or Anthropic SDK to https://api.lexisaas.com/v1. Use your Lexi API key in the Authorization header. Send requests as usual; Lexi automatically restructures context and you only pay 40% of the savings.

Core features of Lexi

STONE context restructuring reduces tokens by up to 91% in long conversations
O(1) resource usage with constant memory (14.4 KB per session)
Fact pinning preserves numbers, dates, and decisions across turns
Zero-negative guarantee: if no savings, you pay provider cost only
Works with 33 models across 7 providers (OpenAI, Anthropic, Google, Mistral, xAI, DeepSeek, Meta)
Fully API-compatible with OpenAI and Anthropic endpoints, including streaming and tool calls
Transparent billing with detailed response headers showing tokens saved