dev/content/docs/index.mdx

---
title: Introduction
description: ZAP — Infinitely faster. Zero-copy Application Protocol for the age of AI & crypto.
---

# ZAP

**ZAP** (Zero-copy Application Protocol) is an insanely fast data interchange format and capability-based RPC system built for the age of AI & crypto.

Think JSON, except binary. Think Protocol Buffers, except faster. In fact, in benchmarks, ZAP is **∞ TIMES** faster than Protocol Buffers.

## Why Infinitely Faster?

This benchmark is, of course, unfair. It only measures the time to encode and decode a message in memory. ZAP gets a perfect score because **there is no encoding/decoding step**.

The ZAP encoding is appropriate both as a data interchange format AND an in-memory representation. Once your structure is built, you can simply write the bytes straight out to disk!

## Platform Independent

The encoding is defined byte-for-byte independent of any platform. However, it is designed to be efficiently manipulated on common modern CPUs:

- **Struct-like layout** — fixed widths, fixed offsets, proper alignment
- **Pointer-based** — variable-sized elements embedded as offset pointers
- **Position independent** — pointers are relative, not absolute
- **Little-endian** — most CPUs are little-endian; big-endian CPUs have conversion instructions

## Backwards Compatible

New fields are always added to the end of a struct (or replace padding space), so existing field positions are unchanged. The recipient simply does a bounds check when reading each field.

Fields are numbered in the order they were added, so ZAP always knows how to arrange them for compatibility.

## Smart Compression

Fixed-width integers, unset optional fields, and padding do add zeros on the wire. However, ZAP applies an extremely fast packing scheme to remove them:

- Achieves similar (often better) message sizes than protobuf
- Still faster than protobuf encoding
- For bandwidth-critical paths, apply general compression (zlib, LZ4) on top

## Security

ZAP does NOT just cast a buffer pointer to a struct pointer. That would be dangerous.

ZAP generates classes with accessor methods that validate pointers before following them. Invalid pointers (out-of-bounds, etc.) throw exceptions or return defaults — your choice.

ZAP powers **Hanzo AI**'s distributed inference infrastructure and **Lux Network**'s consensus layer — environments where both security and microsecond-level performance are paramount. ZAP has undergone fuzzing and expert security review.

## Superpowers

### Incremental Reads
Start processing a ZAP message before receiving all of it. Outer objects appear entirely before inner objects.

### Random Access
Read just one field without parsing the whole message. Jump directly to the data you need.

### Memory Mapping
Read large ZAP files via `mmap`. The OS won't even read the parts you don't access.

### Inter-Language Communication
Java, Python, C++, Rust — all operate on the same in-memory structure. No slow serialization between languages.

### Shared Memory IPC
Multiple processes share ZAP messages via shared memory. No kernel pipes. Calling another process is as fast as calling another thread.

### Arena Allocation
All objects allocated in arenas. Faster than protobuf's scattered allocations. Better cache locality.

### Tiny Generated Code
Just inline accessor methods. Order of magnitude smaller than protobuf's parsing/serialization code.

### Tiny Runtime
Simple format = tiny library. Less code to ship, audit, and maintain.

### Time-Travel RPC
ZAP's RPC system implements promise pipelining — call results return to clients **before** requests arrive at the server!

## Quick Example

Define your schema:

<SchemaTabs
  zap={`struct Person
  name Text
  birthdate Date  # Field numbers = addition order
  email Text      # for backwards compatibility
  phones List(PhoneNumber)

interface AddressBook
  lookup (id UInt64) -> (person Person)
  search (query Text) -> stream (person Person)`}
  capnp={`@0xa1b2c3d4e5f6a7b8;  # file ID required

struct Person {
  name @0 :Text;
  birthdate @3 :Date;  # Field numbers = addition order
  email @1 :Text;      # for backwards compatibility
  phones @2 :List(PhoneNumber);
}

interface AddressBook {
  lookup @0 (id :UInt64) -> (person :Person);
  search @1 (query :Text) -> stream (person :Person);
}`}
/>

Generate and implement your server (Go):

```go
type addressBookServer struct{}

func (s *addressBookServer) Lookup(ctx context.Context, id uint64) (*Person, error) {
    return db.FindPerson(id)
}

func main() {
    server := zap.NewServer()
    server.Register(&addressBookServer{})
    server.ListenAndServe(":9000")
}
```

Use the generated client:

```go
client, _ := zap.Dial("localhost:9000")
defer client.Close()

person, _ := client.AddressBook().Lookup(ctx, 12345)
fmt.Println(person.Name()) // Zero-copy access!
```

## Next Steps

<Cards>
  <Card title="Quick Start" href="/docs/quick-start">
    Get up and running in 5 minutes
  </Card>
  <Card title="Schema Language" href="/docs/schema">
    Learn the ZAP schema language
  </Card>
  <Card title="Code Generation" href="/docs/codegen">
    Generate type-safe code for your language
  </Card>
  <Card title="RPC System" href="/docs/rpc">
    Build services with ZAP RPC
  </Card>
  <Card title="zip" href="/docs/zip">
    The ZAP-native application server
  </Card>
  <Card title="Tools" href="/docs/tools">
    pb2zap and zap2pb — the complete migration path off protobuf
  </Card>
</Cards>