The protocol-agnostic settlement gateway for the agentic era.
SettlerEngine is a high-performance reverse proxy and facilitator designed to bridge AI agents and digital resources through autonomous payments. It implements the x402 protocol, providing a cryptographically secure, stateless, and persistent way to handle machine-to-machine commerce across multiple EVM-compatible chains. Built with sovereign environments in mind, it supports local communication via Unix Domain Sockets and seamless distribution through Anyisland.
In the emerging agentic economy, AI agents require the ability to discover, negotiate, and pay for resources—API access, compute power, or proprietary data—without human intervention. SettlerEngine acts as the "Stripe for Machines," providing the infrastructure for this autonomous commerce.
At its core, SettlerEngine intercepts unauthenticated requests and issues cryptographic challenges using the x402 Protocol. Agents respond by signing an EIP-712 Intent-to-Pay message, which the engine verifies against blockchain state. By focusing on stateless verification and leveraging cryptographic proofs, SettlerEngine achieves the high throughput necessary for high-frequency agentic interactions while maintaining absolute financial security.
Whether running as a global gateway or a local sidecar for co-located agents, SettlerEngine ensures that every digital interaction is backed by a valid settlement intent, unlocking the full potential of autonomous digital markets.
- x402 Handshake: Native support for HTTP 402 "Payment Required" flows optimized for AI Agent parsing.
- EIP-712 Verification: Secure, typed signature verification ensuring agents only pay exactly what they intended.
- Multi-Chain Native: Out-of-the-box support for Base, Cronos, Avalanche, and Polygon.
- Stateless Authorization: High-speed verification loop that minimizes database latency.
- Persistent Idempotency: CGO-free SQLite backend ensures verified payments are cached across restarts.
- Local-First (UDS): Secure Unix Domain Socket support for ultra-low latency communication between local processes.
- Anyisland Ready: Built-in "Pulse" awareness and auto-registration for the Anyisland sovereign ecosystem.
SettlerEngine compiles into a single, dependency-free binary containing both the proxy and facilitator.
CGO_ENABLED=0 go build -o settler ./cmd/settlerStart a reverse proxy that requires a $1.00 USDC payment on Base Sepolia before forwarding traffic:
./settler proxy -target http://your-api:8081 -amount 1000000 -chain-id 84532Build and run using the provided multi-stage Dockerfile:
docker build -t settler-engine .
docker run -p 8080:8080 settler-engine proxy -target http://host.docker.internal:8081If you use Anyisland, the engine is fully managed:
anyisland install github.com/nathfavour/settlerengineSettlerEngine is designed to be a robust local partner for agents running on the same host.
The engine respects OS standards for data storage:
- Linux:
~/.config/settlerengine/ - macOS:
~/Library/Application Support/settlerengine/ - Windows:
%AppData%\settlerengine\
Local agents can bypass the network stack by connecting to the socket at settler.sock within the data directory. This provides a secure, zero-overhead channel for payment processing and status checks.
SettlerEngine follows Hexagonal Architecture principles:
- Core: Pure domain logic for Invoices and Money.
- Pkg: Reusable adapters for Crypto, Storage (SQLite), and UDS.
- Cmd: Unified entry point for all engine sub-commands.
For a deep dive, see the Architecture Documentation.
MIT License. See LICENSE for details.