Stalwart
Stalwart is an all-in-one open-source mail server written in Rust. Supports SMTP, IMAP, JMAP, and ManageSieve — with DMARC, DKIM, SPF, and ARC. Designed for speed, security, and modern standards. Replace your aging Postfix/Dovecot stack.
- Location
- Remote, USA
- Stage
- Bootstrapped
- Founded
- 2022
- Category
- Open Source
- Funding
- Bootstrapped
- Team
- 1-10
Funding figures as of Jul 2025 · not independently verified
Founders of Stalwart
- Mauro De Gennaro
Frequently asked questions
What does Stalwart do?
Stalwart is an all-in-one open-source mail server written in Rust. Supports SMTP, IMAP, JMAP, and ManageSieve — with DMARC, DKIM, SPF, and ARC. Designed for speed, security, and modern standards. Replace your aging Postfix/Dovecot stack.
Where is Stalwart based?
Stalwart is based in Remote, USA.
When was Stalwart founded?
Stalwart was founded in 2022.
How much has Stalwart raised?
Stalwart is bootstrapped. Funding details have not been disclosed.
Who founded Stalwart?
Stalwart was founded by Mauro De Gennaro.
How Stalwart would pitch themselves
○ Auto-generated01Target customer
Developers + open-source communities + enterprises wanting an OSS-first tool in this category, with optional commercial support.
02Problem they solve
Stalwart is an all-in-one open-source mail server written in Rust. Supports SMTP, IMAP, JMAP, and ManageSieve — with DMARC, DKIM, SPF, and ARC. Designed for speed, security, and modern standards. Replace your aging Post… The category has historically been served by tools that miss the modern workflow this product is built around.
03Key differentiator
Stalwart differentiates on secure and modern open source mail server — and on being bootstrapped. The team prioritises profitability + customer-led growth over VC-fuelled scale. Founded by Mauro De Gennaro.
04Go-to-market strategy
Bootstrapped go-to-market — content-led growth, founder-community presence, and product-led adoption via free or freemium tiers. Profitability + customer-funded expansion over VC capital efficiency.