Jan Data Folder

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
Windows
Linux

~/Library/Application Support/jan

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

~/.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

Go to Settings > Advanced
View Jan Data Folder section
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:

Close Jan completely
Copy the entire Jan folder to the new location
Open Jan and go to Settings > Advanced
Click Change next to Jan Data Folder
Select the new location
Restart Jan

Alternatively:

In Jan, go to Settings > Advanced
Click Change next to Jan Data Folder
Select new location
Choose to Move or Copy existing data
Wait for the transfer to complete
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:

Close Jan
Copy the entire Jan data folder to your backup location
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

Close Jan
Delete or rename the current Jan data folder
Copy your backup to the Jan data folder location
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:

Rename the current data folder (e.g., jan-old)
Start Jan (creates a fresh folder)
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:

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

Large Storage Usage

If the data folder is too large:

Check which models are installed (models are the largest files)
Delete unused models in Settings > Models
Clean up old threads and embeddings
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.

​Overview

​Default Locations

​Folder Structure

​Detailed Structure

​Models Directory

​Threads Directory

​Assistants Directory

​Projects Directory

​Embeddings Directory

​Uploads Directory

​Extensions Directory

​Configuration Files

​settings.json

​providers.json

​Storage Management

​Checking Storage Usage

​Cleaning Up Storage

​Delete Unused Models

​Clear Old Threads

​Remove Embeddings

​Moving the Data Folder

​Backup and Restore

​Creating Backups

​Restoring from Backup

​Troubleshooting

​Corrupted Data Folder

​Missing Models After Update

​Large Storage Usage

​Security Considerations

​Data Encryption

​File Permissions

​API Keys and Tokens

Overview

Default Locations

Folder Structure

Detailed Structure

Models Directory

Threads Directory

Assistants Directory

Projects Directory

Embeddings Directory

Uploads Directory

Extensions Directory

Configuration Files

settings.json

providers.json

Storage Management

Checking Storage Usage

Cleaning Up Storage

Delete Unused Models

Clear Old Threads

Remove Embeddings

Moving the Data Folder

Backup and Restore

Creating Backups

Restoring from Backup

Troubleshooting

Corrupted Data Folder

Missing Models After Update

Large Storage Usage

Security Considerations

Data Encryption

File Permissions

API Keys and Tokens