# Protocols

NATS uses text-based protocols for all communication between clients, servers, and clusters. These protocols are designed to be simple, efficient, and easy to implement.

## Protocol Types

### [Client Protocol](/reference/protocols/client.md)

The fundamental protocol for client-server communication. This text-based protocol defines how clients connect, authenticate, publish messages, create subscriptions, and handle responses. Features include:

* Simple text-based commands (PUB, SUB, UNSUB)
* Optional TLS encryption
* Built-in heartbeat mechanism (PING/PONG)
* Support for request-reply patterns
* Header support for metadata

### [Route Protocol](/reference/protocols/route.md)

Used for intra-cluster communication between NATS servers. Routes create a full mesh topology where every server connects to every other server in the cluster. Key characteristics:

* Automatic message routing between servers
* Interest propagation for efficient message delivery
* Cluster-wide state synchronization
* Fault tolerance and automatic failover

### [Leafnode Protocol](/reference/protocols/leafnode.md)

Enables lightweight, unidirectional connections from edge servers to a central cluster. Ideal for:

* IoT and edge deployments
* Hub-and-spoke architectures
* Reducing bandwidth usage
* Selective message propagation
* Account isolation

### [Gateway Protocol](/reference/protocols/gateway.md)

Connects multiple NATS clusters into a super-cluster while maintaining cluster autonomy. Benefits include:

* Cross-cluster communication
* Geographic distribution
* Interest-only message exchange
* Account mapping and isolation
* Optimized for WAN connections

## Protocol Selection

| Use Case                  | Recommended Protocol |
| ------------------------- | -------------------- |
| Client applications       | Client Protocol      |
| High availability cluster | Route Protocol       |
| Edge/IoT deployments      | Leafnode Protocol    |
| Multi-region/Multi-cloud  | Gateway Protocol     |

## Common Protocol Features

All NATS protocols share these characteristics:

* Text-based - Human-readable for easy debugging
* Lightweight - Minimal overhead for high performance
* Secure - TLS support across all protocols
* Resilient - Automatic reconnection and failover
* Efficient - Interest-based message routing