## 1. Project Overview & Quickstart (stalwartlabs/stalwart)

Secure, scalable mail & collaboration server with comprehensive protocol support πŸ›‘οΈ (IMAP, JMAP, SMTP, CalDAV, CardDAV, WebDAV)

## Features **Stalwart** is an open-source mail & collaboration server with JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV and WebDAV support and a wide range of modern features. It is written in Rust and designed to be secure, fast, robust and scalable. Key features: - **Email** server with complete protocol support: - JMAP: * [JMAP for Mail](https://datatracker.ietf.org/doc/html/rfc8621) server. * [JMAP for Sieve Scripts](https://www.ietf.org/archive/id/draft-ietf-jmap-sieve-22.html). * [WebSocket](https://datatracker.ietf.org/doc/html/rfc8887), [Blob Management](https://www.rfc-editor.org/rfc/rfc9404.html) and [Quotas](https://www.rfc-editor.org/rfc/rfc9425.html) extensions. - IMAP: * [IMAP4rev2](https://datatracker.ietf.org/doc/html/rfc9051) and [IMAP4rev1](https://datatracker.ietf.org/doc/html/rfc3501) server. * [ManageSieve](https://datatracker.ietf.org/doc/html/rfc5804) server. * Numerous [extensions](https://stalw.art/docs/development/rfcs#imap4-and-extensions) supported. - POP3: - [POP3](https://datatracker.ietf.org/doc/html/rfc1939) server. - [STLS](https://datatracker.ietf.org/doc/html/rfc2595) and [SASL](https://datatracker.ietf.org/doc/html/rfc5034) support as well as other [extensions](https://datatracker.ietf.org/doc/html/rfc2449). - SMTP: * SMTP server with built-in [DMARC](https://datatracker.ietf.org/doc/html/rfc7489), [DKIMv2](https://datatracker.ietf.org/doc/draft-ietf-dkim-dkim2-spec/), [DKIMv1](https://datatracker.ietf.org/doc/html/rfc6376), [SPF](https://datatracker.ietf.org/doc/html/rfc7208) and [ARC](https://datatracker.ietf.org/doc/html/rfc8617) support for message authentication. * Strong transport security through [DANE](https://datatracker.ietf.org/doc/html/rfc6698), [MTA-STS](https://datatracker.ietf.org/doc/html/rfc8461) and [SMTP TLS](https://datatracker.ietf.org/doc/html/rfc8460) reporting. * Automated DKIM key rotation and management. * Inbound throttling and filtering with granular configuration rules, sieve scripting, MTA hooks and milter integration. * Distributed virtual queues with delayed delivery, priority delivery, quotas, routing rules and throttling support. * Envelope rewriting and message modification. - **Collaboration** server: - Calendaring and scheduling: - [CalDAV](https://datatracker.ietf.org/doc/html/rfc4791) and [CalDAV Scheduling](https://datatracker.ietf.org/doc/html/rfc6638) support. - [JMAP for Calendars](https://datatracker.ietf.org/doc/html/draft-ietf-jmap-calendars-24) support. - Contact management: - [CardDAV](https://datatracker.ietf.org/doc/html/rfc6352) support. - [JMAP for Contacts](https://datatracker.ietf.org/doc/html/rfc9610) support. - File storage: - [WebDAV](https://datatracker.ietf.org/doc/html/rfc4918) support. - [JMAP for File Storage](https://datatracker.ietf.org/doc/html/draft-ietf-jmap-filenode-03) support. - Sharing with fine-grained access controls: - [WebDAV ACL](https://datatracker.ietf.org/doc/html/rfc3744) support. - [JMAP Sharing](https://datatracker.ietf.org/doc/html/rfc9670) support. - **Spam** and **Phishing** built-in filter: - Comprehensive set of filtering **rules** on par with popular solutions. - LLM-driven spam filtering and message analysis. - Statistical **spam classifier** with collaborative filtering, automatic training capabilities and address book integration. - DNS Blocklists (**DNSBLs**) checking of IP addresses, domains, and hashes. - Collaborative digest-based spam filtering with **Pyzor**. - **Phishing** protection against homographic URL attacks, sender spoofing and other techniques. - Trusted **reply** tracking to recognize and prioritize genuine e-mail replies. - Sender **reputation** monitoring by IP address, ASN, domain and email address. - **Greylisting** to temporarily defer unknown senders. - **Spam traps** to set up decoy email addresses that catch and analyze spam. - **Flexible**: - Pluggable storage backends with **RocksDB**, **FoundationDB**, **PostgreSQL**, **mySQL**, **SQLite**, **S3-Compatible**, **Azure** and **Redis** support. - Full-text search available in 17 languages using the built-in search engine or via **Meilisearch**, **ElasticSearch**, **OpenSearch**, **PostgreSQL** or **mySQL** backends. - Sieve scripting language with support for all [registered extensions](https://www.iana.org/assignments/sieve-extensions/sieve-extensions.xhtml). - Email aliases, mailing lists, subaddressing and catch-all addresses support. - Automated DNS management. - Automatic account configuration and discovery with [autoconfig](https://www.ietf.org/id/draft-bucksch-autoconfig-02.html) and [autodiscover](https://learn.microsoft.com/en-us/exchange/architecture/client-access/autodiscover?view=exchserver-2019). - Multi-tenancy support with domain and tenant isolation. - Disk quotas per user and tenant. - **Secure and robust**: - Encryption at rest with **S/MIME** or **OpenPGP**. - Automatic TLS certificate provisioning with [ACME](https://datatracker.ietf.org/doc/html/rfc8555) using `TLS-ALPN-01`, `DNS-01`, `DNS-PERSIST-01` or `HTTP-01` challenges. - Automated blocking of IP addresses that attack, abuse or scan the server for exploits. - Rate limiting. - Security audited (read the [report](https://stalw.art/blog/security-audit)). - Memory safe (thanks to Rust). - **Scalable and fault-tolerant**: - Designed to handle growth seamlessly, from small setups to large-scale deployments of thousands of nodes. - Built with **fault tolerance** and **high availability** in mind, recovers from hardware or software failures with minimal operational impact. - Peer-to-peer cluster coordination or with **Kafka**, **Redpanda**, **NATS** or **Redis**. - **Kubernetes**, **Apache Mesos** and **Docker Swarm** support for automated scaling and container orchestration. - Read replicas, sharded blob storage and in-memory data stores for high performance and low latency. - **Authentication and Authorization**: - **OpenID Connect** authentication. - OAuth 2.0 authorization with [authorization code](https://www.rfc-editor.org/rfc/rfc8628) and [device authorization](https://www.rfc-editor.org/rfc/rfc8628) flows. - **LDAP**, **OIDC**, **SQL** or built-in authentication backend support. - Two-factor authentication with Time-based One-Time Passwords (`2FA-TOTP`) - Application passwords (App Passwords). - Roles and permissions. - Access Control Lists (ACLs). - **Observability**: - Logging and tracing with **OpenTelemetry**, journald, log files and console support. - Metrics with **OpenTelemetry** and **Prometheus** integration. - Webhooks for event-driven automation. - Alerts with email and webhook notifications. - Live tracing and metrics. - **Web-based administration**: - Dashboard with real-time statistics and monitoring. - Account, domain, group and mailing list management. - SMTP queue management for messages and outbound DMARC and TLS reports. - Report visualization interface for received DMARC, TLS-RPT and Failure (ARF) reports. - Configuration of every aspect of the mail server. - Log viewer with search and filtering capabilities. - Self-service portal for password reset and encryption-at-rest key management. ## Screenshots ## Presentation **Want a deeper dive?** Need to explain to your boss why Stalwart is the perfect fit? Whether you're evaluating options, making a case to your team, or simply curious about how it all works under the hood, these slides walk you through the key features, architecture, and benefits of Stalwart. Browse the [slides](https://stalw.art/slides) to see what makes it stand out. ## Get Started Install Stalwart on your server by following the instructions for your platform: - [Linux / MacOS / FreeBSD](https://stalw.art/docs/install/platform/linux) - [Windows](https://stalw.art/docs/install/platform/windows) - [Docker](https://stalw.art/docs/install/platform/docker) All documentation is available at [stalw.art/docs](https://stalw.art/docs/install/get-started). ## Support If you are having problems running Stalwart, found a bug, or just have a question, please head to the [Stalwart Support Portal](https://support.stalw.art) at [support.stalw.art](https://support.stalw.art). Additionally, you may purchase an [Enterprise License](https://stalw.art/enterprise) to obtain priority support from Stalwart Labs LLC, including response-time commitments and a private Priority Support area on the portal. ## Contributing We welcome contributions, but to keep the project maintainable there are a few things to know before opening a pull request. Because of the high volume of low-quality, AI-generated submissions, pull requests are limited to a list of vouched contributors; to be added, post at [support.stalw.art](https://support.stalw.art) describing the change you would like to submit, together with a link to the proposed change. At this stage only bug fixes and translations are accepted, and new features are not, unless they involve just a few lines of code. For the full guidelines, please read [CONTRIBUTING.md](CONTRIBUTING.md). ## Roadmap Stalwart has reached an exciting point in its journey, it’s now **feature complete**. All the core functionality and open standard email and collaboration protocols that we set out to support are in place. In other words, Stalwart already does everything you’d expect from a modern, standards-compliant mail and collaboration platform. The next major milestone is all about refinement: finalizing the database schema and focusing on performance optimizations to ensure everything runs as efficiently and reliably as possible. Once that’s done, we’ll be ready to roll out version **1.0**. Of course, development doesn’t stop there. The community has contributed hundreds of great ideas for improvements and new features, everything from subtle usability tweaks to entirely new integrations. You can see the full list of proposals over on our [GitHub issues](https://github.com/stalwartlabs/stalwart/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc+label%3Aenhancement). If there’s something you’d like to see prioritized, just give it a thumbs up as we plan to implement enhancements based on the community’s votes. ## Sponsorship Your support is crucial in helping us continue to improve the project, add new features, and maintain the highest level of quality. By [becoming a sponsor](https://opencollective.com/stalwart), you help fund the development and future of Stalwart. As a thank-you, sponsors who contribute $5 per month or more will automatically receive a [Enterprise edition](https://stalw.art/enterprise/) license. And, sponsors who contribute $30 per month or more, also have access to [Premium Support](https://stalw.art/support) from Stalwart Labs. ## Funding Part of the development of this project was funded through: - [NGI0 Entrust Fund](https://nlnet.nl/entrust), a fund established by [NLnet](https://nlnet.nl/) with financial support from the European Commission's [Next Generation Internet](https://ngi.eu/) programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 101069594. - [NGI Zero Core](https://nlnet.nl/NGI0/), a fund established by [NLnet](https://nlnet.nl/) with financial support from the European Commission's programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 101092990. If you find the project useful you can help by [becoming a sponsor](https://opencollective.com/stalwart). Thank you! ## License This project is dual-licensed under the **GNU Affero General Public License v3.0** (AGPL-3.0; as published by the Free Software Foundation) and the **Stalwart Enterprise License v2 (SELv2)**: - The [GNU Affero General Public License v3.0](./LICENSES/AGPL-3.0-only.txt) is a free software license that ensures your freedom to use, modify, and distribute the software, with the condition that any modified versions of the software must also be distributed under the same license. - The [Stalwart Enterprise License v2 (SELv2)](./LICENSES/LicenseRef-SEL.txt) is a proprietary license designed for commercial use. It offers additional features and greater flexibility for businesses that do not wish to comply with the AGPL-3.0 license requirements. Each file in this project contains a license notice at the top, indicating the applicable license(s). The license notice follows the [REUSE guidelines](https://reuse.software/) to ensure clarity and consistency. The full text of each license is available in the [LICENSES](./LICENSES/) directory. ## Copyright Copyright (C) 2020, Stalwart Labs LLC ## 2. Official Technical Reference & Guides (stalwartlabs/website) # Stalwart Website The marketing site, documentation, and blog for [Stalwart](https://stalw.art). Built with [Astro 6](https://astro.build) and [Starlight](https://starlight.astro.build); deployed as a static site to Cloudflare Pages. ## Stack - **Marketing pages** (`/`, `/pricing`, `/about`, `/legal/*`, etc.) are Astro pages driven by YAML/Markdown content collections under [src/content/pages/](src/content/pages/) and [src/content/legal/](src/content/legal/). - **Documentation** (`/docs/...`) is rendered by Starlight from [src/content/docs/docs/](src/content/docs/docs/). The previous release line lives at [src/content/docs/docs/0.15/](src/content/docs/docs/0.15/) and is served at `/docs/0.15/...`. - **Blog** (`/blog`, `/blog/`) is the [`starlight-blog`](https://starlight-blog-docs.vercel.app/) plugin reading posts from [src/content/docs/blog/](src/content/docs/blog/). - **Search** is [Pagefind](https://pagefind.app), the offline static-site search baked into Starlight. The index is rebuilt on every `npm run build`. No third-party service or API key needed. - **Per-post OG images** are generated by [`astro-og-canvas`](https://github.com/delucis/astro-og-canvas) at `/og/blog/.png` and referenced from `` on each blog post. - **View Transitions** (smooth cross-page nav) are enabled site-wide via Astro's ``. ## Local development Requirements: Node.js 20+ (set in [package.json](package.json) `engines`). ```sh npm install # one-time, installs Astro + Starlight + plugins npm run dev # http://127.0.0.1:8787 with hot reload ``` `npm run dev` watches every Markdown, Astro and YAML file. Edits reload in the browser within a second; structural changes (new files, frontmatter schema changes) may require a manual reload. Other useful scripts: ```sh npm run build # production build to dist/, runs link validation npm run preview # serve dist/ at http://127.0.0.1:8787 to verify ``` ## Authoring docs Drop new pages into `src/content/docs/docs/
/.md`. Frontmatter must include at least a `title:`. Optional helpful fields: ```yaml --- title: My new page sidebar: order: 5 # position within the parent group badge: New # appears in the sidebar --- ``` To rename a directory's sidebar label or change ordering, drop a `_meta.yml` into that directory ([starlight-auto-sidebar docs](https://starlight-auto-sidebar.netlify.app/metadata/)): ```yaml label: Storage settings order: 5 ``` Admonitions (notes, tips, warnings) use the same triple-colon syntax as before: ```md :::tip Enterprise feature This feature ships with the Enterprise edition. ::: ``` Internal doc links use absolute paths without the `.md` suffix: `[Storage](/docs/storage/overview)`. ## Authoring blog posts Add `src/content/docs/blog/.mdx` (or a folder with `index.mdx` if the post has its own assets). Required frontmatter: ```yaml --- title: Post title date: 2026-05-01 authors: [mdecimus] # keys are defined in astro.config.mjs starlightBlog config tags: [release, jmap] excerpt: | One paragraph teaser shown on the index, in tag pages, and in the RSS feed. --- ``` Reading time is computed automatically. ## Deployment (Cloudflare Pages) The site is a static export. Cloudflare Pages picks up the Astro project automatically; the only config needed in the dashboard is: - **Build command:** `npm run build` - **Build output directory:** `dist` - **Node version:** `20` (or newer) [wrangler.toml](wrangler.toml) declares the same so `wrangler pages deploy` works locally or from CI. Static asset behaviour and redirects are controlled by: - [public/_headers](public/_headers): cache-control and security headers - [public/_redirects](public/_redirects): Docusaurus-era URL redirects - [public/robots.txt](public/robots.txt): AI/search crawler policy - [public/llms.txt](public/llms.txt): curated machine-readable doc index To deploy from your laptop (one-off): ```sh npm run build npx wrangler pages deploy dist --project-name stalwart-website ``` ## Repository layout ``` . β”œβ”€β”€ astro.config.mjs # Astro + Starlight integration config β”œβ”€β”€ src/ β”‚ β”œβ”€β”€ content.config.ts # Astro content collection schemas β”‚ β”œβ”€β”€ content/ β”‚ β”‚ β”œβ”€β”€ docs/ β”‚ β”‚ β”‚ β”œβ”€β”€ docs/ # current docs -> /docs/... β”‚ β”‚ β”‚ β”œβ”€β”€ docs/0.15/ # archived 0.15 -> /docs/0.15/... β”‚ β”‚ β”‚ └── blog/ # blog posts -> /blog/... β”‚ β”‚ β”œβ”€β”€ pages/ # marketing pages (YAML) β”‚ β”‚ └── legal/ # long-form legal pages (Markdown) β”‚ β”œβ”€β”€ components/ # Astro components shared by marketing + docs β”‚ β”‚ β”œβ”€β”€ Header.astro # marketing nav β”‚ β”‚ β”œβ”€β”€ Footer.astro # marketing footer β”‚ β”‚ β”œβ”€β”€ StarlightHeader.astro # Starlight Header override -> Header β”‚ β”‚ β”œβ”€β”€ StarlightFooter.astro # Starlight Footer override -> Footer β”‚ β”‚ └── VersionPicker.astro # docs version dropdown β”‚ β”œβ”€β”€ layouts/ # marketing layouts (Base, LongForm) β”‚ β”œβ”€β”€ pages/ # marketing dynamic routes β”‚ └── styles/ # global tokens and Starlight overrides β”œβ”€β”€ public/ # static assets copied as-is to dist/ └── scripts/ # one-off migration scripts (kept for reference) ``` ## Things to know - The `links-validator` plugin runs at the end of `npm run build` and fails the build on broken internal links. Pre-existing broken links in `/docs/0.15/**` are excluded (see `astro.config.mjs`); fix-forward only. - Mermaid diagrams (`` ```mermaid ``) are converted to client-rendered SVG via the `mermaid` npm package; the script is bundled into Starlight pages only. - The `.old/` directory is the archived Docusaurus tree, kept out of git via `.gitignore` until you choose to delete it.