NHTSA VIN Decoder

World-class VIN decoder with comprehensive offline database (2,015+ WMI codes) and NHTSA vPIC API integration

Author: Wal33D Email: aquataze@yahoo.com

⚡ Quick Start

Java - Offline Mode (No Internet Required)

import io.github.vindecoder.offline.OfflineVINDecoder;
import io.github.vindecoder.nhtsa.VehicleData;

OfflineVINDecoder decoder = new OfflineVINDecoder();
VehicleData vehicle = decoder.decode("1HGCM82633A004352");

System.out.println(vehicle.getModelYear() + " " +
                   vehicle.getMake() + " " +
                   vehicle.getModel());
// Output: 2003 Honda Accord

Python - With NHTSA API

from python.nhtsa_vin_decoder import NHTSAVinDecoder

decoder = NHTSAVinDecoder()
vehicle = decoder.decode("1HGCM82633A004352")

print(f"{vehicle.year} {vehicle.make} {vehicle.model}")
# Output: 2003 Honda Accord

Python - Offline Mode

from python.wmi_database import WMIDatabase

manufacturer = WMIDatabase.get_manufacturer("1HGCM82633A004352")
year = WMIDatabase.get_year("1HGCM82633A004352")

print(f"{year} {manufacturer}")
# Output: 2003 Honda

🎯 Overview

Advanced VIN decoder featuring both enhanced offline decoding capabilities and official NHTSA vPIC API integration. Provides complete vehicle specifications through manufacturer-specific decoders and a comprehensive WMI database with 2,015+ manufacturer codes.

✨ Features

• Enhanced Offline Decoder - Full VIN decoding without internet
• 2,015+ Manufacturer Codes - Comprehensive WMI database (6x industry standard)
• Manufacturer-Specific Decoders - Detailed model/trim/engine extraction
• VIN Validation - Check digit verification per ISO 3779
• Year Decoding - Accurate model year extraction (1980-2039)
• Official NHTSA API - Falls back to government database when online
• Automatic Fallback - Seamlessly switches between offline/online
• FREE - No API key required
• Caching - Built-in LRU cache to reduce API calls
• Multi-platform - Java/Android and Python implementations

📁 Directory Structure

nhtsa-vin-decoder/
├── java/io/github/vindecoder/
│   ├── offline/                    # Offline decoder implementation
│   │   ├── OfflineVINDecoder.java  # Main offline decoder
│   │   ├── VINValidator.java       # VIN validation & structure
│   │   ├── WMIDatabase.java        # 948+ manufacturer codes
│   │   └── MercedesBenzDecoder.java # Example manufacturer decoder
│   └── nhtsa/                      # NHTSA API integration
│       ├── VINDecoderService.java
│       ├── VehicleData.java
│       └── NHTSAApiService.java
├── python/                         # Python implementation
│   ├── nhtsa_vin_decoder.py       # Main decoder with API
│   └── wmi_database.py            # Offline WMI database
├── data/                          # Reference data (not used at runtime)
│   ├── *.csv                      # Source WMI data from WALL-E/vin-decoder
│   ├── process_wmi.py             # Script to regenerate database
│   └── wmi_database_generated.java # Generated code
└── docs/                          # Documentation
    ├── ADDING_DECODERS.md        # Guide for adding manufacturers
    ├── VIN_DECODER_RESOURCES.md  # External data sources
    ├── API.md                    # Complete API reference
    ├── INSTALLATION.md           # Setup guide
    ├── USAGE.md                  # Examples and best practices
    └── WMI_DATABASE.md          # Offline database details

🚀 What You Get

Offline Decoding (No Internet Required)

{
  "vin": "4JGDA5HB7JB158144",
  "make": "Mercedes-Benz",
  "manufacturer": "Mercedes-Benz (Daimler AG)",
  "model": "GLE-Class",
  "year": "2018",
  "trim": "GLE 350 4MATIC",
  "vehicle_type": "Sport Utility Vehicle (SUV)",
  "body_class": "Sport Utility Vehicle (SUV)",
  "doors": "4",
  "drive_type": "4MATIC",
  "engine_model": "3.5L V6",
  "engine_cylinders": "6",
  "engine_displacement_l": "3.5",
  "fuel_type": "Gasoline",
  "transmission_style": "Automatic",
  "transmission_speeds": "9",
  "plant_city": "Tuscaloosa",
  "plant_state": "Alabama",
  "plant_country": "United States",
  "gvwr": "6062",
  "curb_weight": "4630"
}

Online Mode (Full NHTSA Data)

All of the above PLUS safety ratings, recalls, NCAP data, and more.

💻 Quick Start

Java - Offline Mode (No Internet)

import io.github.vindecoder.offline.OfflineVINDecoder;
import io.github.vindecoder.nhtsa.VehicleData;

OfflineVINDecoder decoder = new OfflineVINDecoder();
VehicleData vehicle = decoder.decode("4JGDA5HB7JB158144");

System.out.println("Vehicle: " + vehicle.getModelYear() + " " +
                   vehicle.getMake() + " " + vehicle.getModel());
// Output: Vehicle: 2018 Mercedes-Benz GLE-Class

System.out.println("Trim: " + vehicle.getTrim());
// Output: Trim: GLE 350 4MATIC

System.out.println("Engine: " + vehicle.getEngineModel());
// Output: Engine: 3.5L V6

Java - With NHTSA API

VINDecoderService decoder = VINDecoderService.getInstance();

decoder.decodeVIN("4JGDA5HB7JB158144", new VINDecoderCallback() {
    @Override
    public void onSuccess(VehicleData vehicle) {
        // Full NHTSA data returned
        System.out.println("Vehicle: " + vehicle.getDisplayName());
    }

    @Override
    public void onError(String error) {
        // Automatically falls back to offline decoder
        VehicleData vehicle = new OfflineVINDecoder().decode(vin);
    }
});

🧪 Testing

Java (Year Decoding Test)

• Using Gradle (recommended):

./gradlew test

This runs JUnit tests validating VIN model year decoding across the 30-year cycle, including 2031–2039 (digit codes with position 7 letter heuristic).

Python (Year Decoding Test)

• Run tests:

python3 tests/test_year.py

This validates the Python WMI fallback year-decoding heuristic matches the Java logic.

Python

from python.nhtsa_vin_decoder import NHTSAVinDecoder

decoder = NHTSAVinDecoder()
vehicle = decoder.decode("4JGDA5HB7JB158144")

print(f"Vehicle: {vehicle.year} {vehicle.make} {vehicle.model}")
# Output: Vehicle: 2018 Mercedes-Benz GLE-Class

📊 Offline Decoder Coverage

Global Manufacturer Support (2,015+ WMI Codes)

North America (Complete)

• United States: Ford, GM, Tesla, Rivian, Lucid
• Canada: All manufacturers
• Mexico: All manufacturers

Europe (Comprehensive)

• Germany: Mercedes-Benz, BMW, Audi, Porsche, Volkswagen
• Italy: Ferrari, Lamborghini, Alfa Romeo, Maserati
• UK: Jaguar, Land Rover, Aston Martin, Bentley, Rolls-Royce
• France: Renault, Peugeot, Citroën, Bugatti

Asia (Extensive)

• Japan: Toyota, Honda, Nissan, Mazda, Subaru, Mitsubishi
• Korea: Hyundai, Kia, Genesis
• China: BYD, NIO, XPeng, Geely, and 200+ manufacturers

Special Vehicle Types

• Motorcycles: Harley-Davidson, Yamaha, Honda, Ducati, BMW
• Commercial: Freightliner, Kenworth, Peterbilt, Mack
• Buses: Blue Bird, Thomas, Gillig
• Agricultural: John Deere
• Electric: Tesla, Rivian, Lucid, Polestar, Fisker

Manufacturer-Specific Decoders

Currently implemented:

• Mercedes-Benz: 115+ model variants with full specs
• Ford: 100+ model codes including F-Series, Mustang, Explorer, Edge
• GM: Chevrolet, Cadillac, Buick, GMC with RPO engine codes
• Toyota/Lexus: Comprehensive model and engine coverage

Easily extensible for:

• Honda, BMW, Nissan, etc.
• See ADDING_DECODERS.md for implementation guide

🔍 Comparison

Current Capabilities (What We Actually Have)

Feature	Our Offline Decoder	NHTSA API (Online)	Basic WMI Only
Manufacturer	✓ 2,015+ codes	✓ All	~100-300 codes
Make	✓ All from WMI	✓ All	✓ Limited
Model	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
Year	✓ 1980-2039	✓ All	✗
Trim/Series	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
Engine Details	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
Transmission	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
Body Style	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
Drive Type	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
Plant Location	✓ Basic all	✓ Detailed	✗
Weight Specs	✓ Ford, GM, Toyota, Mercedes*	✓ All	✗
VIN Validation	✓ ISO 3779	✓	Basic
Check Digit	✓ Full validation	✓	✗
Region/Country	✓ All	✓ All	✓ Basic
Safety Data	✗	✓ NCAP ratings	✗
Recall Data	✗	✓	✗
Works Offline	✓ Always	✗ Needs internet	✓
Speed	<1ms	200-500ms	<1ms
Free	✓	✓	✓

*Can be extended to other manufacturers by adding decoders (see ADDING_DECODERS.md)

📈 Recent Improvements

Version 2.0 (October 2025)

• 6x More Coverage: Increased from 311 to 2,015+ WMI codes
• Fixed Year Bug: Now correctly decodes 2010+ model years
• 4 Manufacturer Decoders: Mercedes-Benz, Ford, GM, Toyota/Lexus with full specs
• Enhanced Validation: ISO 3779 check digit verification
• Extensible Architecture: Easy to add new manufacturers
• Reference Data: CSV sources included for transparency

🛠️ Installation

Java/Android

// Add as submodule
git submodule add https://github.com/Wal33D/nhtsa-vin-decoder.git modules/nhtsa-vin-decoder

// For NHTSA API support, add:
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'

Python

# No external dependencies for offline mode
from python.wmi_database import WMIDatabase

# For API support:
pip install requests  # Optional, uses urllib by default

📚 Documentation

• ADDING_DECODERS.md - Add manufacturer-specific decoders
• VIN_DECODER_RESOURCES.md - External data sources
• API Reference - Complete API documentation
• WMI Database - Offline database details

🔧 Extending the Decoder

Adding a New Manufacturer Decoder

See ADDING_DECODERS.md for complete guide.

Quick example for Ford:

public class FordDecoder {
    public static VehicleInfo decode(String vin) {
        // Extract model codes, engine, transmission
        // See MercedesBenzDecoder.java for reference
    }
}

Updating WMI Database

cd data/
# Edit CSV files to add new codes
python3 process_wmi.py
# Copy generated code to WMIDatabase.java

🧩 Using As a Gradle Submodule

• Add this repo as a Git submodule, e.g. under modules/nhtsa-vin-decoder.
• In your root settings.gradle (or settings.gradle.kts) include the project:

include ':nhtsa-vin-decoder'
project(':nhtsa-vin-decoder').projectDir = new File(rootDir, 'modules/nhtsa-vin-decoder')

• In your app module build.gradle add a dependency:

implementation project(':nhtsa-vin-decoder')

• If you use the online NHTSA API classes, add runtime dependencies in your app:

implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
implementation 'com.google.code.gson:gson:2.10.1'

⚡ Performance

Speed Comparison

Operation	Time	Throughput	Use Case
Offline Decode	<1ms	1,000+ VINs/sec	Real-time apps, mobile
Online Decode	200-500ms	~2-5 VINs/sec	Complete data needed
Batch Offline	0.5s/1000 VINs	2,000 VINs/sec	Fleet management
Batch Online (parallel)	10s/100 VINs	~10 VINs/sec	Background processing

Why Offline Mode is 500x Faster

Offline:  VIN → HashMap lookup → Result (0.8ms)
Online:   VIN → HTTP request → NHTSA server → Response parsing → Result (350ms)

Resource Usage

• Memory: ~100KB for WMI database (2,015+ codes)
• Storage: ~500KB total (includes manufacturer decoders)
• CPU: Negligible (<1% for typical usage)
• Network: Zero for offline mode, ~5KB per VIN for online

Real-World Performance Test

# Test: Decode 1,000 VINs
# Hardware: MacBook Pro M1, 16GB RAM

Offline mode:  0.534 seconds (1,873 VINs/sec)
Online mode:   342.8 seconds (2.9 VINs/sec)
Speedup:       642x faster

When to Use Each Mode

Use Offline Mode When:

• Speed is critical (<1ms response time)
• Working without internet connection
• Processing large batches (1,000+ VINs)
• Building mobile/embedded apps
• Need basic info (manufacturer, year, region)

Use Online Mode When:

• Need complete vehicle specifications
• Want safety ratings and recall data
• Require NCAP test results
• Need detailed engine/transmission specs
• Accuracy is more important than speed

🎯 Use Cases

• OBD-II Apps - Vehicle context without internet
• Fleet Management - Offline vehicle identification
• Insurance - Quick VIN validation
• Parts Lookup - Accurate model/engine matching
• Automotive Tools - Professional diagnostic apps
• Classic Cars - Decode vintage VINs (1980+)

🤝 Contributing

Found a missing WMI code or want to add a manufacturer decoder?

1. Fork the repository
2. Add codes to data/*.csv or create new decoder in java/io/github/vindecoder/offline/
3. Submit PR with test results

📄 License

MIT License - Free for commercial and non-commercial use

📧 Contact

Wal33D - aquataze@yahoo.com Repository: https://github.com/Wal33D/nhtsa-vin-decoder

🙏 Credits

• NHTSA for providing the free vPIC API
• WALL-E/vin-decoder for WMI CSV data
• ISO for VIN standards (ISO 3779:2009)
• US Department of Transportation

🔮 Roadmap

• Ford decoder (positions 4-8 patterns)
• GM/Chevrolet decoder
• Toyota/Lexus decoder
• Honda/Acura decoder
• BMW decoder (17-character patterns)
• Nissan/Infiniti decoder