Jan Data Folder

Understanding Jan’s data folder structure and file organization

Overview

The Jan Data Folder is where all application data is stored locally on your computer. This includes models, conversations, settings, and extensions.

Default Locations

Jan stores data in different locations based on your operating system:

macOS

~/Library/Application Support/jan

Windows

C:\Users\[YourUsername]\AppData\Roaming\jan

Linux

~/.config/jan

You can view and change the data folder location in Settings > Advanced > Jan Data Folder.

Folder Structure

The Jan data folder is organized into several subdirectories:

jan/
├── models/           # Downloaded AI models
├── threads/          # Conversation threads
├── assistants/       # Custom assistants
├── projects/         # Project configurations
├── extensions/       # MCP servers and plugins
├── embeddings/       # Vector databases for RAG
├── uploads/          # Attached files and images
├── settings.json     # App configuration
└── providers.json    # Model provider settings

Detailed Structure

Models Directory

Stores all downloaded model files:

models/
├── [provider]/
│   ├── [model-name]/
│   │   ├── model.gguf       # Model weights
│   │   ├── model.json       # Model metadata
│   │   └── mmproj.gguf      # Vision projection weights (if applicable)
│   └── ...

Example:

models/
├── llamacpp/
│   ├── llama-3-8b-instruct/
│   │   ├── llama-3-8b-instruct-q5_k_m.gguf
│   │   └── model.json
│   ├── llava-1.6-vicuna-7b/
│   │   ├── llava-v1.6-vicuna-7b-q5_k_m.gguf
│   │   ├── mmproj-vicuna-7b-f16.gguf
│   │   └── model.json

Model files are typically large (2GB-40GB+). Ensure adequate storage space before downloading.

Threads Directory

Stores conversation history:

threads/
├── [thread-id]/
│   ├── thread.json          # Thread metadata
│   └── messages.jsonl       # Message history (JSONL format)

thread.json example:

{
  "id": "thread_abc123",
  "title": "Python debugging help",
  "created_at": 1234567890,
  "updated_at": 1234567890,
  "model": {
    "id": "llama-3-8b-instruct",
    "provider": "llamacpp"
  },
  "assistants": [{
    "id": "asst_xyz789",
    "name": "Code Assistant"
  }],
  "metadata": {
    "hasDocuments": false,
    "project": null
  }
}

messages.jsonl example:

{"id":"msg_1","role":"user","content":[{"type":"text","text":{"value":"Hello"}}],"created_at":1234567890}
{"id":"msg_2","role":"assistant","content":[{"type":"text","text":{"value":"Hi there!"}}],"created_at":1234567891}

Assistants Directory

Stores custom assistant configurations:

assistants/
├── [assistant-id].json

Assistant file example:

{
  "id": "asst_abc123",
  "name": "Code Reviewer",
  "avatar": "🤖",
  "description": "Reviews code for best practices",
  "instructions": "You are an expert code reviewer...",
  "created_at": 1234567890,
  "parameters": {
    "temperature": 0.3,
    "max_tokens": 2000,
    "presence_penalty": 0.1
  }
}

Projects Directory

Stores project configurations and metadata:

projects/
├── [project-id]/
│   ├── project.json         # Project settings
│   └── files/               # Project-specific files

project.json example:

{
  "id": "proj_xyz789",
  "name": "Documentation Project",
  "assistantId": "asst_abc123",
  "created_at": 1234567890,
  "updated_at": 1234567890,
  "metadata": {
    "color": "blue",
    "icon": "📁"
  }
}

Embeddings Directory

Stores vector databases for RAG (Retrieval Augmented Generation):

embeddings/
├── threads/
│   └── [thread-id]/          # Thread-specific embeddings
│       ├── index.faiss       # Vector index
│       └── metadata.json     # Document metadata
├── projects/
│   └── [project-id]/         # Project-wide embeddings
│       ├── index.faiss
│       └── metadata.json

Embeddings are created when you attach documents with RAG mode enabled. They allow semantic search across your documents.

Uploads Directory

Stores attached files and images:

uploads/
├── [thread-id]/
│   ├── [file-id].pdf
│   ├── [file-id].png
│   └── ...

Files are named using unique identifiers and organized by thread.

Extensions Directory

Stores MCP servers and plugin configurations:

extensions/
├── mcp/
│   ├── servers.json          # MCP server configurations
│   └── logs/                 # Server logs
└── plugins/                  # Future plugin support

servers.json example:

{
  "filesystem": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/dir"],
    "env": {},
    "enabled": true
  },
  "github": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-github"],
    "env": {
      "GITHUB_PERSONAL_ACCESS_TOKEN": "***"
    },
    "enabled": false
  }
}

Configuration Files

settings.json

Main application settings:

{
  "appearance": {
    "theme": "dark",
    "fontSize": "medium",
    "language": "en"
  },
  "chat": {
    "spellCheck": true,
    "tokenCounterCompact": false
  },
  "rag": {
    "enabled": true,
    "parseMode": "auto",
    "maxFileSizeMB": 10,
    "autoInlineContextRatio": 0.75
  },
  "server": {
    "host": "127.0.0.1",
    "port": 0
  },
  "updates": {
    "autoCheck": true,
    "autoDownload": true
  }
}

providers.json

Model provider configurations:

{
  "llamacpp": {
    "provider": "llamacpp",
    "enabled": true,
    "models": [
      {
        "id": "llama-3-8b-instruct",
        "name": "Llama 3 8B Instruct",
        "settings": {
          "ctx_len": 8192,
          "ngl": 35,
          "n_parallel": 1
        },
        "capabilities": ["text", "tools"]
      }
    ]
  },
  "openai": {
    "provider": "openai",
    "enabled": false,
    "apiKey": "***",
    "baseUrl": "https://api.openai.com/v1",
    "models": []
  }
}

Storage Management

Checking Storage Usage

1. Go to Settings > Advanced
2. View Jan Data Folder section
3. See total storage used

Cleaning Up Storage

Delete Unused Models

models/[provider]/[unused-model]/

Remove model directories you no longer need.

Clear Old Threads

threads/[old-thread-id]/

Delete conversation directories you don’t need to keep.

Remove Embeddings

embeddings/threads/[thread-id]/

Delete vector databases for old threads.

Deleting threads and embeddings is permanent. Export conversations you want to keep before deletion.

Moving the Data Folder

To relocate your Jan data:

1. Close Jan completely
2. Copy the entire Jan folder to the new location
3. Open Jan and go to Settings > Advanced
4. Click Change next to Jan Data Folder
5. Select the new location
6. Restart Jan

Alternatively:

1. In Jan, go to Settings > Advanced
2. Click Change next to Jan Data Folder
3. Select new location
4. Choose to Move or Copy existing data
5. Wait for the transfer to complete
6. Restart Jan

When moving to a new drive, ensure it has sufficient space for all your models and data.

Backup and Restore

Creating Backups

Manual backup:

1. Close Jan
2. Copy the entire Jan data folder to your backup location
3. Include all subdirectories

Automated backup:

# macOS/Linux
cp -r ~/Library/Application\ Support/jan /path/to/backup/jan-backup-$(date +%Y%m%d)

# Windows (PowerShell)
Copy-Item -Path "$env:APPDATA\jan" -Destination "C:\Backups\jan-backup-$(Get-Date -Format 'yyyyMMdd')" -Recurse

Restoring from Backup

1. Close Jan
2. Delete or rename the current Jan data folder
3. Copy your backup to the Jan data folder location
4. Restart Jan

Selective restore: You can restore individual components (threads, assistants, models) by copying only specific subdirectories.

Troubleshooting

Corrupted Data Folder

If Jan fails to start:

1. Rename the current data folder (e.g., jan-old)
2. Start Jan (creates a fresh folder)
3. Selectively copy back data from jan-old:
   • Start with settings.json
   • Then assistants/
   • Then threads/
   • Finally models/ (if not corrupted)

Missing Models After Update

If models disappear after an update:

1. Check Settings > Advanced > Jan Data Folder
2. Verify the path is correct
3. Open the folder and check models/ directory
4. If models exist but aren’t showing, restart Jan
5. If still missing, re-import from the folder

Large Storage Usage

If the data folder is too large:

1. Check which models are installed (models are the largest files)
2. Delete unused models in Settings > Models
3. Clean up old threads and embeddings
4. Consider moving to a larger drive

A typical Jan installation with 2-3 models uses 10-50GB of storage. Large models (70B parameters) can exceed 40GB each.

Security Considerations

Data Encryption

• Jan data is stored unencrypted by default
• Use full-disk encryption (FileVault, BitLocker) for protection
• Sensitive conversations should be stored on encrypted volumes

File Permissions

Jan data folder permissions:

# macOS/Linux - should be user-only
chmod 700 ~/Library/Application\ Support/jan

# Windows - ensure only your user has access

API Keys and Tokens

Stored in providers.json and extensions/mcp/servers.json:

• Never commit these files to version control
• Use environment variables for sensitive values
• Rotate keys regularly

If sharing backups, remove sensitive files (providers.json, MCP configs) or redact API keys.