Building an IPC Communication Layer in Go: Unix Sockets vs gRPC

Modern applications are rarely a single process. Desktop applications, security agents, networking tools, and system daemons often consist of multiple components that need to communicate with each other efficiently.

Recently, while working on a service, I had to design an Inter Process Communication (IPC) layer between a desktop application and a background service. This led to an interesting design discussion:

Should we use Unix Domain Sockets or gRPC?

In this article, I’ll explore both approaches, discuss message format choices, and cover security considerations that are often overlooked.

What is IPC?

Inter-Process Communication (IPC) refers to mechanisms that allow independent processes running on the same machine to exchange information.

Common IPC methods include:

• Unix Domain Sockets
• Named Pipes
• Shared Memory
• Message Queues
• gRPC over local sockets
• HTTP over localhost

A typical architecture looks like: Desktop Client < — IPC → Background Service

The IPC layer becomes a critical component because every command, configuration update, and status request flows through it.

Approaches

Option 1: Unix Domain Sockets

Unix Domain Sockets (UDS) provide socket-based communication between processes on the same machine.

Creating a Unix socket server in Go is straightforward:

listener, err := net.Listen("unix", "/tmp/admin.sock")
if err != nil {
    log.Fatal(err)
}

for {
    conn, err := listener.Accept()
    if err != nil {
        continue
    }
    go handleConnection(conn)
}

Client side:

conn, err := net.Dial("unix", "/tmp/admin.sock")
if err != nil {
    log.Fatal(err)
}

Advantages

• Low Overhead
• No HTTP/TCP stack.
• Minimal serialization requirements.
• Communication remains entirely local to the machine.
• Unix sockets typically outperform localhost TCP communication because data never traverses the network stack.

File System Permissions

The socket file itself can be protected:

chmod 600 /tmp/admin.sock

This provides an additional security boundary.

Simplicity

For small command-response workflows, UDS can be extremely lightweight.

Example:

{
  "command": "get_status"
}

Response:

{
  "connected": true
}

Disadvantages

Custom Protocol Design

You must define:

• Message framing
• Request identifiers
• Error handling
• Versioning
• Serialization format

Everything becomes your responsibility.

Harder Cross Platform Support

Unix sockets work well on Linux and macOS.

Windows support has historically been more complex, although newer versions support Unix sockets.

Maintenance Cost

As the protocol evolves, maintaining custom IPC formats becomes challenging.

Option 2: gRPC

gRPC provides a strongly typed RPC framework built on Protocol Buffers.

Example service definition:

service DeviceService {
  rpc RegisterDevice(RegisterRequest)
      returns (RegisterResponse);
}

Generated Go code provides both client and server implementations automatically.

Server:

grpcServer := grpc.NewServer()

pb.RegisterDeviceServiceServer(
    grpcServer,
    server,
)

Client:

client := pb.NewDeviceServiceClient(conn)

resp, err := client.RegisterDevice(
    ctx,
    req,
)

Advantages

Strong Contracts

The protocol definition becomes the single source of truth.

message RegisterRequest {
  string device_id = 1;
}

Both client and server share the same contract.

Automatic Code Generation

No need to manually:

• Parse messages
• Validate structures
• Maintain serialization logic

Built-In Features

gRPC provides:

• Streaming
• Deadlines
• Retries
• Authentication hooks
• Interceptors
• Error handling out of the box.

Easier Versioning

Protocol Buffers were designed with backward compatibility in mind.

Fields can be added safely:

message User {
  string id = 1;
  string email = 2;
}

Later:

message User {
  string id = 1;
  string email = 2;
  string role = 3;
}

Older clients continue to function.

Disadvantages

More Complexity

For simple command-response workflows, gRPC can feel heavy.

You need:

• Proto definitions
• Code generation
• Dependency management

Debugging

A JSON payload is easy to inspect. A binary protobuf payload requires tooling.

Learning Curve

Developers unfamiliar with Protocol Buffers need time to understand the ecosystem.

Message Format Choices

Regardless of transport, you still need a message format.

JSON

Example:

{
  "device_id": "abc123"
}

Pros:

• Human readable
• Easy debugging
• Language independent

Cons:

• Larger payloads
• Slower serialization

Protocol Buffers

Example:

message Device {
  string id = 1;
}

Pros:

• Compact
• Fast
• Strong typing

Cons:

• Less readable
• Requires code generation

Security Considerations

This is where many IPC implementations fail.

IPC is often treated as “internal”, leading developers to ignore security entirely.

That is dangerous.

Authenticate Requests

Do not assume any local process is trusted.

Verify:

• User identity
• Process ownership
• Session context

For privileged operations, perform explicit authorization checks.

Restrict Socket Permissions

For Unix sockets:

chmod 600 admin.sock

Ensure only intended users can access the socket.

Validate All Input

Never trust incoming data.

Validate:

• Length
• Types
• Required fields
• Allowed values

Even local IPC endpoints can be abused.

Prevent Denial of Service

Implement:

• Request size limits
• Connection limits
• Timeouts

Audit Sensitive Operations

Log:

• Device registration
• Authentication events
• Configuration changes
• Administrative actions

These logs become invaluable during investigations.

Which One Should You Choose?

My rule of thumb is simple:

Use Unix Sockets When

• Communication is local only
• Protocol is small
• Performance matters
• Few message types exist

Examples:

• Local daemon control
• Status queries
• Lightweight agents

Use gRPC When

• The protocol will grow
• Multiple teams consume the API
• Strong contracts matter
• Versioning is important

Examples:

• Enterprise products
• Security platforms
• Long-lived services
• Multi-language clients

Final Thoughts

The transport layer is only one piece of IPC design.

The real challenges usually emerge later:

• Protocol evolution
• Backward compatibility
• Security
• Observability
• Operational maintenance

For small systems, Unix Domain Sockets provide an elegant and high-performance solution.

For larger systems expected to evolve over years, gRPC’s strong contracts and tooling often justify the additional complexity.

The best IPC solution is not necessarily the fastest one. It is the one your team can safely maintain, secure, and evolve over time.