Zwift Log Parser

A TypeScript command-line tool for parsing and analyzing Zwift activity log files. Built with Bun and React Ink.

Features

• 📊 FPS Analysis — Visualize frame rate performance with ASCII graphs and statistics
• 🗺️ Route Tracking — Identify routes/activities with duration, distance, and elevation data
• 🌍 World Sessions — Track world changes and activity segments
• 💻 System Information — Extract GPU, CPU, RAM, resolution, and graphics settings
• 🎮 Session Metadata — View game version, launcher version, device info, and timestamps
• 📤 JSON Export — Output data as JSON for further processing
• 🔧 Flexible Options — Enable/disable specific analysis sections as needed
• 📁 Interactive File Picker — Browse and select log files if no path is provided

Installation

From npm

npm install -g zwift-log-parser
zwift-log-parser /path/to/your/Log.txt

Local Development

git clone https://github.com/chrisjwalk/zwift-log-parser.git
cd zwift-log-parser
bun install
bun run build
npm link          # makes the zwift-log-parser command available globally
zwift-log-parser /path/to/your/Log.txt

Usage

Basic Usage

zwift-log-parser /path/to/Log.txt

If no file path is provided, an interactive file picker will launch:

zwift-log-parser

Command-Line Options

zwift-log-parser [logfile] [options]

Arguments:
  logfile            Path to Zwift log file to parse

Options:
  -V, --version      Output the version number
  --no-fps           Skip FPS analysis and graphs
  --no-routes        Skip route/activity information
  --no-metadata      Skip session and system metadata
  --json             Output results as JSON instead of formatted display
  -h, --help         Display help information

Examples

# Analyze everything (default)
zwift-log-parser ~/Documents/Zwift/Logs/Log.txt

# Routes and metadata only, no FPS graph
zwift-log-parser ~/Documents/Zwift/Logs/Log.txt --no-fps

# Export to JSON for further processing
zwift-log-parser ~/Documents/Zwift/Logs/Log.txt --json > output.json

# FPS analysis only
zwift-log-parser ~/Documents/Zwift/Logs/Log.txt --no-routes --no-metadata

Sample Output

🚴 Zwift Log Parser v0.0.1

Session Information
  Log Date/Time:  21:09:07 2026-01-08
  Game Version:   1.104.4(157262) rc/1.104.4
  Device:         PC

System Information
  GPU:            NVIDIA GeForce RTX 5060/PCIe/SSE2
  Driver:         4.6.0 NVIDIA 591.74
  CPU:            12th Gen Intel(R) Core(TM) i5-12600KF
  RAM:            64GB
  Resolution:     1920x1080
  Graphics:       ultra

Worlds
  Watopia
  • Triple Flat Loops
  • The Big Ring

FPS Analysis

  📍 Watopia

     126.00 ┤
     121.33 ┤  ╭───╮                     ╭──────╮
     116.67 ┼──╯   │        ╭╮           │      ╰╮
     ...

  Time: 1h 48m 52s | Average: 99.76 | Min: 61.73 | Max: 120.97

Development

Project Structure

This is a Bun workspace monorepo with two packages:

core/                       # Parser library (@zwift-log-parser/core)
├── src/
│   ├── index.ts            # Library entry point
│   └── lib/
│       ├── parser.ts       # ZwiftLogParser class
│       ├── file-picker.ts  # Interactive file picker
│       └── __fixtures__/   # Test data (real log files)
└── package.json

cli/                        # CLI application
├── src/
│   ├── main.tsx            # Entry point — argument parsing
│   ├── App.tsx             # Root React Ink component
│   └── components/         # Individual UI panel components
│       ├── Banner.tsx
│       ├── MetadataPanel.tsx
│       ├── WorldsPanel.tsx
│       ├── FpsPanel.tsx
│       └── Section.tsx
└── package.json

scripts/
└── build.ts                # Bun build script (bundles CLI via esbuild)

bin/
└── zwift-log-parser.js     # npm bin wrapper

Available Commands

bun install              # Install dependencies
bun run build            # Build CLI bundle to dist/
bun run dev              # Run CLI directly with Bun (no build needed)
bun start                # Run the built CLI from dist/
bun test                 # Run all tests
bun lint                 # Lint all source files with ESLint
bun run clean            # Remove build artifacts
bun run pack             # Create npm tarball in dist/

Development Workflow

# 1. Install dependencies
bun install

# 2. Run directly without building (fastest iteration)
bun run dev /path/to/Log.txt

# 3. Build for production
bun run build

# 4. Test the built bundle
bun start /path/to/Log.txt

# 5. Run tests
bun test

# 6. Lint
bun lint

Publishing to npm

# Bump version, build, and publish
npm version patch
bun run build
npm publish --access public

To test the package locally before publishing:

bun run pack
npm install -g dist/zwift-log-parser-<version>.tgz

Technology Stack

• Runtime: Bun
• Language: TypeScript 6.0
• UI: React Ink 7 (terminal UI, React 19)
• Bundler: esbuild (via Bun build API)
• CLI Arg Parsing: Commander.js
• FPS Graphs: asciichart
• File Picker: @inquirer/prompts
• Testing: Vitest
• Linting: ESLint 10 + typescript-eslint

Architecture

Core Library (@zwift-log-parser/core)

Provides the ZwiftLogParser class and pickFile() utility:

• parseMetadata(content) — session and system info
• parseRouteSessions(content) — routes and world sessions with timing
• parseFPSLines(content) — raw FPS sample array
• parseFpsPerWorld(content) — FPS data grouped by world, with timestamps
• calculateFpsStats(fps) — average, min, max statistics
• downsampleData(data, width) — reduce data points for graph rendering

CLI Application

Built with React Ink — the terminal output is a rendered React component tree. Commander.js handles argument and option parsing before React renders.

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

License

MIT