foropensource

Helpmonks Hosted Edition (shared inbox)

Helpmonks Hosted Edition (SaaS shared team inbox / email management) free of charge for open source projects; nonprofits instead get a discount of up to 30% on all plans.

Eligibility: for the project; non-commercial only; public repo required; Code must be publicly available (GitHub, Bitbucket, etc.) with proof the project is actively used; commercial open source projects are not accepted. Requests are evaluated individually.

How to apply: Create a free Helpmonks account, then email hi@helpmonks.com with the account details and information about the project and its online presence.

last verified 2026-07-06

Pro plan (open source sponsorship program)

Free Pro tier for qualifying open source projects: 50,000 transactional emails per month via SMTP relay and HTTP API, unlimited verified domains, premium IP pool, inbound routing/webhooks, and delivery analytics; higher volume available on request.

Eligibility: for the project; OSI license required; non-commercial only; public repo required; Public repo on GitHub/GitLab/Codeberg or similar; maintainership verified via a project-linked email address; for the project itself, not commercial products.

How to apply: Submit repository URL, license type, sending use case and estimated monthly volume via the contact form on the offer page; review takes about two business days.

last verified 2026-07-07

KaiMail email forwarding for custom domains

Free program for open source projects and volunteer communities to use their own domain for email: custom-domain addresses (e.g. contact@, sponsors@, security@) with forwarding, DKIM/ARC signing, no mail server, no per-seat fees.

Eligibility: for the project; Open source projects and volunteer communities; detailed criteria not published, set up per request.

How to apply: Contact KaiMail and tell them about your project or community ("tell us about it and we will get you set up").

last verified 2026-07-06

Hosted Mailman 3 mailing lists

Free hosting of GNU Mailman 3 mailing lists on the mailman3.com SaaS for open source software projects ("We love open-source software and provide free hosting for OSS mailing lists").

Eligibility: for the project; Must be an open source software project; no further published criteria — applications are reviewed per request.

How to apply: Email hostmaster@mailman3.com with the project URL and approximate monthly email volume.

last verified 2026-07-06