Welcome to Isartor

Open-source Prompt Firewall — deflect up to 95% of redundant LLM traffic before it leaves your infrastructure.

Pure Rust · Single Binary · Zero Hidden Telemetry · Air-Gappable

AI coding agents and personal assistants repeat themselves — a lot. Copilot, Claude Code, Cursor, and OpenClaw send the same system instructions, the same context preambles, and often the same user prompts across every turn. Standard API gateways forward all of it to cloud LLMs regardless.

Isartor sits between your tools and the cloud. It intercepts every prompt and runs a cascade of local algorithms — from sub-millisecond hashing to in-process neural inference — to resolve requests before they reach the network. Only the genuinely hard prompts make it through.

The Deflection Stack

Every incoming request passes through a sequence of smart computing layers. Only prompts requiring genuine, complex reasoning survive the stack to reach the cloud.

Request ──► L1a Exact Cache ──► L1b Semantic Cache ──► L2 SLM Router ──► L2.5 Context Optimiser ──► L3 Cloud Logic
                 │ hit                │ hit                 │ simple             │ compressed                │
                 ▼                    ▼                     ▼                    ▼                           ▼
              Response             Response            Local Response     Optimised Prompt            Cloud Response

Layers 1a and 1b deflect 71% of repetitive agentic traffic and 38% of diverse task traffic before any neural inference runs.

How It Works

Getting started with Isartor takes three steps:

1. Install

curl -fsSL https://raw.githubusercontent.com/isartor-ai/Isartor/main/install.sh | sh

Or use Docker:

docker run -p 8080:8080 ghcr.io/isartor-ai/isartor:latest

2. Connect

Point any OpenAI-compatible client at Isartor — just change the base URL:

import openai

client = openai.OpenAI(
    base_url="http://localhost:8080/v1",
    api_key="your-api-key",
)

Works with the official SDKs, LangChain, LlamaIndex, AutoGen, GitHub Copilot, OpenClaw, and any other OpenAI-compatible tool.

Recent OpenAI-compatible improvements for coding agents include:

• GET /v1/models for model discovery
• stream: true support on /v1/chat/completions with proper SSE chunks
• tools, tool_choice, functions, and function_call passthrough
• tool_calls preserved in upstream responses

3. Save

Isartor deflects repetitive and simple prompts locally. You keep the same responses, pay for fewer tokens, and get lower latency — with zero code changes beyond the URL.

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