frontier/README_en.md

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Bidirectional service-to-edge gateway for long-lived connections

Frontier is an open-source gateway written in Go for service <-> edge communication. It lets backend services and edge nodes talk to each other over long-lived connections, with built-in bidirectional RPC, messaging, and point-to-point streams.

It is built for systems where both sides stay online and need to actively call, notify, or open streams to each other. Frontier is not a reverse proxy and not just a message broker. It is infrastructure for addressing and operating large fleets of connected edge nodes from backend services.

What Makes Frontier Different

• Different from API gateways: Frontier is designed for backend-to-edge communication, not just north-south HTTP traffic.
• Different from MQ: It gives you bidirectional RPC, messaging, and streams in one connectivity model.
• Different from tunnels: Services can address a specific online edge node instead of only exposing a port.
• Made for real fleets: Works for devices, agents, clients, and remote connectors that stay online for a long time.

What You Can Build

Traffic relay and media streaming Open point-to-point streams for RTMP relay, file transfer, proxy traffic, or other custom protocols.

Remote agents and device fleets Keep edge nodes online, route service calls to a specific edge, and let the edge call backend services back.

At A Glance

You need to...	Frontier gives you...
Call a specific online device or agent from your backend	Service -> Edge RPC and messaging over long-lived connections
Let edge nodes initiate calls without opening inbound ports	Edge -> Service RPC on the same connection model
Move bytes, not just request/response payloads	Point-to-point streams between service and edge
Run one control plane for a large connected fleet	Presence, lifecycle hooks, control APIs, clustering

Table of Contents

• Why Frontier
• What Makes Frontier Different
• What You Can Build
• At A Glance
• When to Use Frontier
• Real-World Use Cases
• Comparison
• Quick Start
• Docs
• Community
• License

Why Frontier

Most infrastructure is optimized for one of these models:

• service -> service via HTTP or gRPC
• client -> service via API gateways and reverse proxies
• event fan-out via message brokers

Frontier is optimized for a different model:

• service <-> edge over long-lived, stateful connections
• backend services calling a specific online edge node
• edge nodes calling backend services without exposing inbound ports
• opening direct streams between services and edge nodes when RPC is not enough

When to Use Frontier

Use Frontier if you need:

• Backend services to call specific online devices, agents, clients, or connectors
• Edge nodes to call backend services over the same connectivity model
• Long-lived connections at large scale
• One data plane for RPC, messaging, and streams
• Cluster deployment and high availability for service-to-edge connectivity

Do not use Frontier if:

• You only need service-to-service RPC; gRPC is a simpler fit
• You only need HTTP ingress, routing, or proxying; use an API gateway or Envoy
• You only need pub/sub or event streaming; use NATS or Kafka
• You only need a generic tunnel; use frp or another tunneling tool

Real-World Use Cases

• IoT and device fleets
• Remote agents and connectors
• IM and other real-time systems
• Game backends talking to online clients or edge nodes
• Zero-trust internal access based on connector-style agents
• File transfer, media relay, or traffic proxy over point-to-point streams

Use Cases In One Screen

Scenario	Why Frontier fits
Device control plane	Address a specific online edge node, push commands, receive state, and keep the link alive
Remote connector platform	Let connectors dial out, avoid inbound exposure, and keep service-side routing simple
Real-time apps	Maintain long-lived sessions and combine notifications, RPC, and streams in one path
Internal zero-trust access	Use agent-style edges as the last-mile bridge between backend systems and private resources

Comparison

Capability	Frontier	gRPC	NATS	frp	Envoy
Built for service <-> edge communication	Yes	No	Partial	No	No
Backend can address a specific online edge node	Yes	No	Partial	Partial	No
Edge can call backend services	Yes	Partial	Yes	No	No
Point-to-point streams between service and edge	Yes	Partial	No	Tunnel only	No
Unified RPC + messaging + streams model	Yes	No	No	No	No
Long-lived connection fleet as a primary model	Yes	No	Partial	Partial	No

Partial here means the capability can be assembled with extra patterns, but it is not the system's primary communication model.

Quick Start

1. Start a single Frontier instance:

docker run -d --name frontier -p 30011:30011 -p 30012:30012 singchia/frontier:1.2.2

2. Build the examples:

make examples

3. Run the chatroom demo:

# Terminal 1
./bin/chatroom_service

# Terminal 2
./bin/chatroom_agent

The chatroom example shows the basic Frontier interaction model: long-lived connectivity, edge online/offline events, and service <-> edge messaging.

You can also run the RTMP example if you want to see Frontier's stream model used for traffic relay:

# Terminal 1
./bin/rtmp_service

# Terminal 2
./bin/rtmp_edge

Demo video:

https://github.com/singchia/frontier/assets/15531166/18b01d96-e30b-450f-9610-917d65259c30

Docs

README is intentionally optimized for fast understanding and fast conversion. The implementation details, configuration surface, deployment playbooks, and cluster operations live in the docs.

Start here:

• Usage Guide
• Configuration Guide
• Technical Docs Index
• Systemd Deployment
• Docker Compose Deployment
• Helm and Operator Deployment
• Roadmap

If you are evaluating Frontier for production, the docs cover:

• architecture and communication model
• RPC, messaging, and point-to-point stream semantics
• deployment on Docker, Compose, Helm, and Operator
• cluster mode with Frontlas and Redis
• development workflow and contribution guidelines

Community

Join our WeChat group for discussions and support.

License

Released under the Apache License 2.0

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