BICHON

A self-hosted email archiving server built in Rust. Download emails from IMAP accounts, builds a full-text search index, and serves a REST API with an embedded WebUI. Purpose-built for long-term preservation, unified cross-account search, and programmatic access to archived email.

▶ Click to watch the demo

Contents

• Features
• Quick Start
  • Docker (Recommended)
  • Docker Compose
  • Binary Installation
  • Build from Source
• Configuration Reference
  • Required Settings
  • Server & Networking
  • Logging
  • CORS
  • TLS & HTTPS
  • SMTP Server
  • Storage Paths
  • Performance Tuning
• Authentication & RBAC
• CLI Tools
• API Reference
• Import & Export
• Architecture
• Storage & Backup
• Internationalization
• Data Migration (v0.x → v1.0)
• FAQ
• Roadmap
• Contributing
• Tech Stack
• License

Features

• Multi-Account IMAP Download: Download multi-account concurrently. Supports password (PLAIN/LOGIN) and OAuth 2.0 (SASL XOAUTH2) with automatic token refresh and PKCE. SSL/TLS, STARTTLS, or plain connections with optional self-signed certificate acceptance.
• Incremental Download: UID-based delta fetching downloads only new messages after the initial download. UIDVALIDITY changes are detected and trigger automatic cache rebuilds.
• Fetch Scoping: Filter download by date range, mailbox folder limit, or specific folder names. Configurable per-account SOCKS5 proxy routing.
• Auto-Configuration: Discover IMAP server settings automatically from an email domain.
• Full-Text Search: Search across subject, body, sender, recipients, attachment properties, and more. Optimized for European languages.
• Advanced Filters: Date range, size range, attachment presence, file type, content category, and facet-based tag combinations.
• Thread Grouping: Reconstruct and view complete conversation threads across folders.
• Attachment Search: Browse and filter attachments by sender, file type, size, and other attachment properties.
• Faceted Tags: Add, remove, or overwrite tags on messages and attachments. Filter by tag combinations with real-time count updates.
• Contacts View: Extracted and deduplicated sender/recipient address book across all authorized accounts.
• Three-Layer Storage: Tantivy for full-text indexing (Zstd compression), Fjall with LZ4 for compressed blob storage, and memdb for relational metadata. All embedded — zero external dependencies.
• Content Deduplication: Identical email bodies and attachments stored once via BLAKE3 content hashing. Folder moves update metadata only.
• Dashboard Analytics: Email volume trends, top senders, storage usage breakdown, attachment statistics, and per-account activity. Scoped by user permissions.
• OpenAPI 3.0: Interactive API documentation at /api-docs (Swagger UI, ReDoc, Scalar). All endpoints documented with request/response schemas.
• Multi-User RBAC: 5 built-in roles (Admin, Manager, Member, AccountManager, AccountViewer) plus custom roles with 22 granular permissions.
• Account-Level Isolation: Grant users access to specific accounts with scoped roles. Permissions enforced at the API layer.
• CLI Import Tools: Import from EML directories, MBOX files (including Gmail variants), Thunderbird profiles, and Outlook PST files.
• CLI Export: Download account data as MBOX via bichon-cli.
• Bulk Restore: Restore emails in bulk back to their original IMAP accounts.
• Embedded SMTP Server: Receive emails directly at the gateway level. STARTTLS or TLS encryption. AUTH PLAIN/LOGIN with API token authentication.
• Admin Tooling: Password reset for locked-out admins. Non-destructive v0.3.7 to v1.0 data migration.
• API Token Management: Create, list, and revoke long-lived API tokens for programmatic access.
• SOCKS5 Proxy Management: Configure and manage proxy profiles for routing IMAP traffic per account.
• Scheduled Download: Configure per-account download schedules using cron expressions. Run syncs at specific times or intervals — for example, nightly-only or business-hours-only archiving.
• Remote Content Blocking: External images and tracking pixels embedded in emails are blocked by default. Users can selectively allow remote content to load on a per-message basis from the WebUI.
• Async Index Deduplication: Duplicate detection in the search index is performed asynchronously, reducing write latency during high-throughput ingestion.

Quick Start

Docker (Recommended)

# Pull the image
docker pull rustmailer/bichon:latest

# Create data directory
mkdir -p ./bichon-data

# Run container
docker run -d \
  --name bichon \
  -p 15630:15630 \
  -v $(pwd)/bichon-data:/data \
  --user 1000:1000 \
  -e BICHON_ROOT_DIR=/data \
  -e BICHON_ENCRYPT_PASSWORD=your-secure-password-here \
  rustmailer/bichon:latest

Open http://localhost:15630 in your browser.

Docker Compose

services:
  bichon:
    image: rustmailer/bichon:latest
    container_name: bichon
    ports:
      - "15630:15630"
    volumes:
      - ./bichon-data:/data
    user: "1000:1000"
    environment:
      BICHON_ROOT_DIR: /data
      BICHON_ENCRYPT_PASSWORD: your-secure-password-here
      BICHON_LOG_LEVEL: info

Binary Installation

Download from the Releases page:

Platform	Archive
Linux (GNU)	bichon-x.x.x-x86_64-unknown-linux-gnu.tar.gz
Linux (MUSL)	bichon-x.x.x-x86_64-unknown-linux-musl.tar.gz
macOS	bichon-x.x.x-x86_64-apple-darwin.tar.gz
Windows	bichon-x.x.x-x86_64-pc-windows-msvc.zip

# Linux / macOS
./bichon --bichon-root-dir /path/to/data --bichon-encrypt-password your-password

# Windows
.\bichon.exe --bichon-root-dir E:\bichon-data --bichon-encrypt-password your-password

--bichon-root-dir must be an absolute path. All Bichon data lives under this directory.

Build from Source

Prerequisites: Rust (latest stable), Node.js 20+, pnpm

git clone https://github.com/rustmailer/bichon.git
cd bichon

# Build the WebUI (required before building the server)
cd web && pnpm install && pnpm run build && cd ..

# Build and run
export BICHON_ENCRYPT_PASSWORD=dev-password
cargo run -- --bichon-root-dir /tmp/bichon-data

For frontend development:

cd web && pnpm run dev   # Vite dev server with API proxy to Rust backend

Configuration Reference

All settings accept both CLI flags (--bichon-http-port) and environment variables (BICHON_HTTP_PORT). CLI flags take precedence over environment variables.

Required Settings

Variable	CLI Flag	Description
BICHON_ROOT_DIR	--bichon-root-dir	Required. Absolute path for all persistent data
BICHON_ENCRYPT_PASSWORD	--bichon-encrypt-password	Password used to encrypt stored credentials (IMAP passwords, OAuth tokens)
BICHON_ENCRYPT_PASSWORD_FILE	--bichon-encrypt-password-file	Alternative: read the encryption password from a file

Server & Networking

Variable	Default	Description
BICHON_HTTP_PORT	15630	HTTP server port
BICHON_BIND_IP	0.0.0.0	IP address to bind to (IPv4 or IPv6)
BICHON_PUBLIC_URL	http://localhost:15630	Public-facing URL used in OAuth redirects and docs
BICHON_BASE_URL	/	Base path for WebUI when behind a reverse proxy (e.g. /bichon)
BICHON_WEBUI_TOKEN_EXPIRATION_HOURS	168	Access token lifetime in hours (default 7 days)
BICHON_HTTP_COMPRESSION_ENABLED	true	Enable gzip/brotli/zstd response compression

Logging

Variable	Default	Description
BICHON_LOG_LEVEL	info	Log level: trace, debug, info, warn, error
BICHON_ANSI_LOGS	true	Colorized terminal output
BICHON_JSON_LOGS	false	JSON-formatted logs for log aggregators
BICHON_LOG_TO_FILE	false	Persist logs to files under root dir
BICHON_MAX_SERVER_LOG_FILES	5	Max log files to retain

CORS

Variable	Default	Description
BICHON_CORS_ORIGINS	(allow all)	Comma-separated list of allowed origins: http://192.168.1.16:15630,http://myserver.local:15630
BICHON_CORS_MAX_AGE	86400	Cache duration for CORS preflight in seconds

TLS & HTTPS

Variable	Default	Description
BICHON_ENABLE_REST_HTTPS	false	Serve the API over HTTPS (requires valid certificate)

SMTP Server

Variable	Default	Description
BICHON_ENABLE_SMTP	false	Enable the embedded SMTP receiver
BICHON_SMTP_PORT	2525	SMTP listening port
BICHON_SMTP_ENCRYPTION	starttls	Encryption mode: none, starttls, or tls
BICHON_SMTP_AUTH_REQUIRED	true	Require authentication for SMTP connections
BICHON_SMTP_TLS_KEY_PATH	—	Absolute path to SMTP TLS private key
BICHON_SMTP_TLS_CERT_PATH	—	Absolute path to SMTP TLS certificate chain

Storage Paths

Variable	Default	Description
BICHON_INDEX_DIR	{root}/bichon-indices	Tantivy full-text index directory
BICHON_DATA_DIR	{root}/bichon-storage	Fjall blob storage directory

Performance Tuning

Variable	Default	Description
BICHON_SYNC_CONCURRENCY	num_cpus × 2	Max concurrent account sync tasks
BICHON_METADATA_CACHE_SIZE	134217728 (128 MB)	Metadata DB cache in bytes
BICHON_ENVELOPE_CACHE_SIZE	134217728 (128 MB)	Envelope index cache in bytes

Authentication & RBAC

Authentication

1. POST /api/login with username + password returns a JWT access token
2. All /api/v1/* endpoints require Authorization: Bearer <token>
3. Tokens expire after the configured duration (BICHON_WEBUI_TOKEN_EXPIRATION_HOURS, default 7 days)
4. Long-lived API tokens can be created via WebUI or API for programmatic access

Default Admin Account

On first start, Bichon creates a built-in admin user:

• Username: admin
• Password: admin@bichon

Built-in Roles

Role	Type	Scope	Description
Admin	Global	Unrestricted	Full system access — users, roles, tokens, all accounts, all data operations
Manager	Global	ACL-scoped	Create accounts, view users, manage authorized accounts and their data
Member	Global	Minimal	Basic login access; data access granted through account-level role assignments
AccountManager	Account	Per-account	Full control over an assigned account — config, sync, data read/write/delete, import, SMTP ingest
AccountViewer	Account	Per-account	Read-only access to an assigned account's messages and metadata

Permission Reference

Global permissions:

Permission	Description
system:access	Login and access the dashboard
system:root	Manage system configurations (OAuth providers, proxy settings)
user:manage	Create, update, and delete users
user:view	View user list and basic profiles
token:manage	View and revoke all API tokens
account:create	Connect new email accounts to the system
account:manage:all	Manage configurations for all email accounts
data:read:all	Search and read messages across all accounts
data:manage:all	Manage tags and metadata for all accounts
data:raw:download:all	Download raw EML files from any account
data:delete:all	Permanently delete messages from any account
data:export:batch:all	Export messages in bulk from all accounts

Account-scoped permissions (require ACL assignment):

Permission	Description
account:manage	Modify configuration and sync settings for authorized accounts
account:read_details	View status and details of authorized accounts
data:read	Read messages from authorized accounts
data:manage	Manage tags and metadata for authorized accounts
data:raw:download	Download raw EML files from authorized accounts
data:delete	Delete messages from authorized accounts
data:export:batch	Export messages from authorized accounts
data:import:batch	Import EML/PST data into authorized accounts
data:smtp:ingest	Receive and archive emails via SMTP for authorized accounts

CLI Tools

bichon-cli — Import & Export

./bichon-cli --config config.toml

Creates a config.toml on first run with your server URL and API token.

Operation	Description
EML Directory	Recursively scan a directory tree of .eml files; preserves folder structure
MBOX	Stream-import from a single .mbox archive (including Gmail's MBOX variant)
Thunderbird	Import directly from a local Thunderbird profile directory
PST	Import from Outlook Personal Storage .pst files
Export to MBOX	Download account data as an .mbox file

All imports are processed server-side — the server handles MIME parsing, indexing, deduplication, and storage.

bichon-admin — Administration

./bichon-admin

Interactive menu with two operations:

Operation	Description
Reset Admin Password	Reset the built-in admin password when locked out
Migrate v0.3.7 → v1.0	Non-destructive migration from legacy storage layout to v1.0 architecture

API Reference

Interactive API documentation is available at:

Endpoint	UI
/api-docs/swagger	Swagger UI
/api-docs/redoc	ReDoc
/api-docs/scalar	Scalar
/api-docs/spec.json	Raw OpenAPI 3.0 JSON
/api-docs/spec.yaml	Raw OpenAPI 3.0 YAML

All /api/v1/* endpoints require Authorization: Bearer <token>.

Import & Export

Supported Formats

Format	Tool	Notes
EML Directory	bichon-cli	Recursive .eml scan; preserves folder hierarchy
MBOX	bichon-cli	Single-file streaming import; supports Gmail's MBOX variant
Thunderbird	bichon-cli	Reads directly from local Thunderbird profile directory
PST	bichon-cli	Outlook Personal Storage (.pst) file parsing
API Import	POST /api/v1/import	Base64-encoded EML payloads for programmatic use
MBOX Export	bichon-cli	Download account data as .mbox file

All imports flow through the Bichon REST API. The server parses MIME, extracts metadata, indexes content into Tantivy, deduplicates by BLAKE3 content hash, and stores raw blobs in Fjall.

Architecture

Workspace Crates

bichon/
├── crates/
│   ├── memdb/         Embedded key-value database layer (WAL, transactions)
│   ├── core/          Library — IMAP sync, search, storage, auth, models
│   ├── server/        Binary — Poem web server + embedded WebUI (rust-embed)
│   ├── cli/           Binary — bichon-cli import/export CLI
│   └── admin/         Binary — bichon-admin password reset & migration
└── web/               React + TypeScript + Vite + ShadCN UI frontend

Three-Layer Storage

Request Layer
    REST API (Poem)  │  WebUI (React)
─────────────────────┼────────────────────
Storage Layer         │
                      │
  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐
  │    memdb     │  │   Tantivy    │  │    Fjall     │
  │  (metadata)  │  │  (full-text) │  │   (blobs)    │
  │              │  │              │  │              │
  │ • accounts   │  │ • envelope   │  │ • raw emails │
  │ • users      │  │ • attachment │  │ • attachments│
  │ • roles      │  │ • tags       │  │   LZ4 compr. │
  │ • config     │  │ • contacts   │  │              │
  │ • proxies    │  │   Zstd compr.│  │ BLAKE3 hash  │
  └──────────────┘  └──────────────┘  └──────────────┘

• memdb: Key-value metadata store. Houses accounts, users, roles, OAuth2 configs, proxy settings, and system configuration.
• Tantivy: Full-text search indices with Zstd compression support. Two separate indices: envelope (email metadata + body text) and attachment (file metadata + extracted text). Batch-committed every 1,000 documents or 60 seconds.
• Fjall: LZ4-compressed LSM tree key-value store. Two keyspaces — email_keyspace and attachments_keyspace. Content-hash addressed (BLAKE3) with insert-time deduplication. Values larger than 1 KB stored as separate files (KV separation).

IMAP Download Pipeline

Schedule tick (every 10s)
        │
        ▼
  reconcile_mailboxes()
  Compare local vs. remote
        │
   ┌────┴────┐
   ▼         ▼
UID OK    UID changed / new
(incremental)  (full rebuild)
   │         │
   ▼         ▼
fetch new   fetch all
(max+1:*)   (1:* batched)
   │         │
   └────┬────┘
        ▼
extract_envelope_and_store_it()
        │
   ┌────┼────┐
   ▼    ▼    ▼
Tantivy Fjall memdb

• Per-account background tasks managed by a global download-task singleton
• Concurrency controlled by semaphore (default: num_cpus × 2)
• Manual sync via POST /api/v1/accounts/:id/start-download; cancel with cancel-download
• Busy-check prevents overlapping manual and automatic syncs on the same account

Content Deduplication & Attachment Storage

                     ┌──────────────────────────────────────────┐
                     │              Raw EML bytes               │
                     └────────────────┬─────────────────────────┘
                                      │
                                      ▼
                     ┌──────────────────────────────────────────┐
                     │         BLAKE3 → email_content_hash      │
                     └────────────────┬─────────────────────────┘
                                      │
                                      ▼
                     ┌──────────────────────────────────────────┐
                     │          MIME parse → Message            │
                     └───────┬──────────────────┬──────────────┘
                             │                  │
                             │     ┌────────────┘
                             │     │  detach attachments
                             │     │
                             ▼     ▼
               ┌─────────────────┐   ┌──────────────────────────────┐
               │  EMAIL BODY     │   │  EACH ATTACHMENT             │
               │                 │   │                              │
               │  Replace raw    │   │  BLAKE3(decoded content)     │
               │  attachment     │   │  → attachment_content_hash   │
               │  bytes with     │   │                              │
               │  placeholder:   │   │  Store raw undecoded bytes   │
               │                 │   │  in Fjall attachments_ks     │
               │  <<BICHON_      │   │  (skip if hash exists)       │
               │   DETACH_HASH:  │   │                              │
               │   xxx>>         │   │  Extract text for indexing   │
               │                 │   │  (PDF, DOCX, etc.)           │
               └───────┬─────────┘   └──────────────┬───────────────┘
                       │                            │
                       ▼                            │
               ┌──────────────────────────────┐     │
               │  Stripped EML stored in      │     │
               │  Fjall email_keyspace        │     │
               │  keyed by email_content_hash │     │
               │  (skip if hash exists)       │     │
               └──────────────┬───────────────┘     │
                              │                     │
                              ▼                     ▼
               ┌─────────────────────────────────────────────────┐
               │           Tantivy full-text index               │
               │  envelope index · attachment index              │
               └─────────────────────────────────────────────────┘

   ═══════════════════════════════════════════════════════════════

   Dedup layers
   ┌─────────────────────────────────────────────────────────────────┐
   │ Fjall (insert-time)                                             │
   │   contains_key(hash)? → skip : store with LZ4 compression       │
   │                                                                 │
   │ Tantivy (periodic, every 12 h)                                  │
   │   Group by (account, mailbox, content_hash)                     │
   │   Keep latest ingest_at → soft-delete older copies              │
   │   Cascade-delete orphaned attachment index entries              │
   └─────────────────────────────────────────────────────────────────┘

   Reconstruction
   ┌─────────────────────────────────────────────────────────────────┐
   │ Fetch stripped EML by content_hash from Fjall                  │
   │ Find <<BICHON_DETACH_HASH:xxx>> placeholders                    │
   │ Replace each with raw attachment blob from Fjall                │
   │ Result → byte-identical original EML                            │
   └─────────────────────────────────────────────────────────────────┘

Every ingested email is hashed with BLAKE3. Attachments are detached from the MIME tree, hashed independently (decoded content), and stored as raw undecoded bytes in Fjall's attachments_keyspace. The email body is patched with hash-based placeholders and stored in email_keyspace. Both keyspaces check for existing hashes before writing — identical content is never stored twice, regardless of which account or folder it arrives in. A periodic index dedup task (every 12 hours) scans Tantivy for duplicate (account, mailbox, content_hash) tuples, keeps the most recently ingested copy, and cascade-deletes orphaned attachment entries so UID-based incremental sync remains accurate. The original EML reconstructs byte-for-byte by swapping placeholders back with their attachment blobs.

Storage & Backup

Data Directory Layout

{root}/
├── bichon-indices/         Tantivy full-text index (envelope + attachment)
├── bichon-storage/         Fjall LZ4-compressed blob store
├── memdb/                  Metadata database (accounts, users, roles, config)
├── logs/                   Server logs (when BICHON_LOG_TO_FILE=true)

Backup

Back up the entire BICHON_ROOT_DIR (and BICHON_INDEX_DIR / BICHON_DATA_DIR if overridden). All three layers must be backed up together for consistency.

# Example with rsync
rsync -avz /path/to/bichon-data/ backup-server:/backups/bichon/

Encryption

Stored credentials (IMAP passwords, OAuth tokens) are encrypted with AES-256-GCM via ring. The encryption key is derived from BICHON_ENCRYPT_PASSWORD.

Internationalization

The WebUI is available in 18 languages:

Code	Language	Code	Language
ar	العربية	it	Italiano
da	Dansk	jp	日本語
de	Deutsch	ko	한국어
en	English	nl	Nederlands
es	Español	no	Norsk
fi	Suomi	pl	Polski
fr	Français	pt	Português
it	Italiano	ru	Русский
zh	中文	sv	Svenska
zh-tw	繁體中文

Language preference and UI theme are saved to your user profile and can be changed anytime from the WebUI settings.

Data Migration (v0.3.7 → v1.x)

Bichon v1.x introduced a redesigned storage architecture:

Layer	v0.3.7 (Legacy)	v1.x
Index	Tantivy (shared instance, no full attachments)	Tantivy (separate envelope + attachment indices)
Raw data	Tantivy (inline, stored in another Tantivy instance)	Fjall (LZ4-compressed LSM-tree key-value store)
Metadata	Native_DB (shared, disk-based DB powered by redb)	memdb (dedicated, in-house in-memory DB)

If you ran Bichon prior to v1.x, migrate your data:

./bichon-admin
# Select "Migrate Legacy v0.3.7 Storage to v1.x"

FAQ

CORS errors when accessing the WebUI

1. Enable debug logging: BICHON_LOG_LEVEL=debug
2. Check the server logs for the incoming Origin header and configured origins
3. Ensure the browser's exact origin matches an entry in BICHON_CORS_ORIGINS (no trailing slash, no wildcards)
4. In Docker, do not quote the value: -e BICHON_CORS_ORIGINS=http://192.168.1.16:15630

"Legacy data layout detected" error on startup

Your data was created by Bichon v0.3.7 and must be migrated. Run ./bichon-admin and select the migration option.

How do I run Bichon behind a reverse proxy?

Set BICHON_BASE_URL=/bichon (or your sub-path) and configure your proxy:

# nginx example
location /bichon/ {
    proxy_pass http://127.0.0.1:15630/;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

Can Bichon send emails?

No. Bichon is an archiver, not an email client. The optional SMTP server receives emails only — it cannot send, forward, or reply.

What hardware does Bichon need?

• Recommended: 4+ CPU cores, 2+ GB RAM (sufficient for 10+ accounts and 200+ GB of archived data)
• Filesystem: use a mainstream Linux filesystem such as ext4 or XFS; avoid network / virtual filesystems (NFS, VirtIO-FS) for all data directories
• Indices benefit from SSD storage; blob storage can use HDD

How do I reset the admin password?

./bichon-admin
# Select "Reset Admin Password"

Where can I get help?

• GitHub Issues
• Discord
• Wiki

Roadmap

• Multi-account IMAP Download (Password + OAuth2)
• Full-text search with faceted tags
• Multi-user support with RBAC and custom roles
• WebUI in 18 languages with dark/light themes
• Dashboard with analytics
• CLI import: EML, MBOX, Thunderbird, PST
• CLI export: MBOX
• Embedded SMTP server
• Data migration tooling (v0.3.7 → v1.0)
• On-demand manual download controls
• Post-download server cleanup (free remote mailbox space)
• Account-to-account email merge / migration
• MCP Server for LLM-powered email search and analysis
• S3-compatible storage backend
• Enterprise SSO (OIDC / SAML)

Contributing

Contributions of all kinds are welcome — code, bug reports, documentation, or feature suggestions.

git clone https://github.com/rustmailer/bichon.git
cd bichon

# Build WebUI
cd web && pnpm install && pnpm run build && cd ..

# Build backend
cargo build

# Run tests
cargo test

Feel free to open an Issue or join the Discord to discuss ideas.

Tech Stack

Layer	Technology
Backend	Rust, Tokio, Poem + Poem OpenAPI
Full-text search	Tantivy (Zstd compression)
Blob storage	Fjall (LSM tree, LZ4 compression, KV separation)
Metadata DB	memdb (embedded key-value store with WAL)
IMAP	async-imap, rustls (ring), SOCKS5 proxy support
SMTP	Embedded receiver (AUTH PLAIN/LOGIN, STARTTLS/TLS)
Cryptography	AES-256-GCM (ring), BLAKE3 (content hashing)
Frontend	React 18, TypeScript, Vite 6, ShadCN UI, TanStack Router/Query/Table
Charts	Recharts
i18n	i18next (18 languages)
Container	Ubuntu 24.04, Docker

License

Bichon is licensed under the GNU Affero General Public License v3.0. Copyright © 2025–2026 rustmailer.com