kaf - High-Performance Kafka TUI

kaf is a robust, terminal-based Kafka client built for speed, safety, and modern data architectures. Unlike other tools, it's designed to be Production-Safe by default, preventing accidental data loss while providing deep insights into your clusters.

Key Features

• 🛡️ Safe by Default: Starts in Read-Only mode. Destructive actions require an explicit --write flag.
• 📦 Data-Aware: Native support for Avro and Protobuf decoding via Confluent Schema Registry.
• 📂 Local Protobuf Support: Decode raw messages without a registry by pointing to your local .proto files.
• 🏷️ Header Visibility: View Kafka Headers at a glance for tracing and metadata debug.
• 🕵️ Sensitive Data Masking: Automatically redact keys like password or token from displayed JSON.
• 🧠 Smart Memory Management: Automatic buffer capping (100MB) and UI virtualization. It won't crash your server.
• 🕵️ Real-time Insights: View consumer group lag and status.
• 🚀 Zero-Config: Interactive setup wizard or environment variables support.

Quick Start

Installation

Pre-built Binaries (Linux, Windows, macOS)

Download the latest binary for your platform from the Releases page.

Go Install

go install github.com/goiriz/kaf/cmd/kaf@latest

From Source

make static
sudo cp kaf /usr/local/bin/

Usage

Run the interactive setup wizard:

kaf setup

Launch with a specific broker:

kaf --broker localhost:9092

Or use environment variables:

export KAFKA_BROKERS="prod-1:9092,prod-2:9092"
kaf

Protobuf Guide

kaf provides two ways to decode Protobuf messages without a Schema Registry:

1. Auto-Discovery (Guessing)

If you provide proto_paths, kaf will scan all .proto files and attempt to decode incoming messages by matching them against all known message types. This is great for exploration.

2. Strict Mode (Mapping)

To prevent incorrect guesses or to explicitly enforce a schema for a topic, use topic_proto_mappings in your config:

topic_proto_mappings:
  "orders-topic": "com.example.Order"
  "users": "User"

In Strict Mode, if a message fails to decode as the mapped type, kaf will display a (Decode Error) and show the raw hex.

3. UI Overrides

While viewing a topic, press v to cycle through decoders:

• AUTO (PROTO/AVRO): Uses Registry, Mappings, or Guessing.
• TEXT/JSON: Forces plain-text or pretty-printed JSON view.
• HEX: Shows the raw binary data.

kaf remembers your decoder choice per topic for the duration of the session.

Keyboard Shortcuts

Key	Action
g	Switch between Topics and Groups modes
C	(Shift+C) Switch Cluster Context
tab	Change focus between Sidebar and Details
c	Tail mode (Real-time stream)
b	History mode (Load last 1000 messages)
y	Copy message to clipboard
v	Cycle decoder (Auto/JSON -> Hex)
?	Show help menu
esc	Go back or Quit

Safety & Compliance

• Anti-OOM Protection: Message buffer is capped at 100MB by default.
• Controller Protection: Metadata requests have a 3s timeout to prevent DoS on large clusters.
• Secure Secrets: Supports password_cmd in configuration to fetch credentials from external vaults (e.g., pass, aws-cli).

Configuration (~/.kaf.yaml)

contexts:
  local:
    brokers: ["localhost:9092"]
  prod:
    brokers: ["kafka-prod:9092"]
    tls: true
    proto_paths: ["./protos", "/home/user/my-app/api"]
    sasl:
      mechanism: "SCRAM-SHA-512"
      username: "admin"
      password_cmd: "pass kafka/prod-password"
    schema_registry_url: "http://schema-registry:8081"
log_path: "/tmp/kaf.log"
log_max_size_mb: 10

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