Rainloop

What Rainloop does

RainLoop is a privately held software company that develops RainLoop Webmail, a lightweight, self-hosted web-based email client implemented in PHP and distributed under both open-source (GNU AGPLv3) and commercial licenses. The product requires only PHP 5.4+ runtime with standard extensions and no database backend (with the limited exception of contacts storage), enabling deployment on modest Apache, NGINX, or lighttpd web servers without the operational complexity typical of comparable webmail stacks.

Functionally, RainLoop provides direct IMAP and SMTP connectivity with SSL/STARTTLS support, Sieve-based server-side filtering, multi-level caching, two-factor authentication, client-side OpenPGP encryption, and a plugin architecture for extensibility. The user-facing differentiation centers on a modern browser-native interface with drag-and-drop, keyboard shortcuts, browser notifications, multi-account support across browser tabs, and integrations with Facebook, Google, Twitter, and Dropbox for social login and file attachment.

RainLoop monetizes via a freemium model: the Community edition is free for non-commercial websites, while commercial use requires a paid Standard edition subscription available as Basic (non-commercial), Premium one-year, and Premium lifetime tiers — each scoped to a single web domain. Distribution is entirely self-serve through rainloop.net, an online demo, a one-line command-line installer, and the project's GitHub repository, with demand generated via SEO, third-party tutorials, and developer-community channels rather than sales-led motion. The company appears to operate as a small independent team with no disclosed venture funding, parent company, or named enterprise customers.

Name

Rainloop

Legal name

RainLoop

Website

https://rainloop.net

Company type

Private

Operating status

Operating

Short description

RainLoop develops a lightweight, self-hosted PHP webmail client distributed as a free AGPLv3 community edition and a paid commercial Standard edition, serving SMBs, hosting providers, and developers needing minimal-resource email frontends with no database backend.

Ownership category

akta.pro rank

GTM type

B2B

Offering type

Software

Cost components

Personnel, Technology or R&D, Operations, Infrastructure, Marketing or Sales

Revenue model

1. Commercial Software Licensing: Commercial license (subscription) required for using RainLoop Webmail on commercial websites. Subscribers can use the Standard edition with premium features including one-click updater and custom branding options.
2. Premium Subscriptions: Premium one-year subscription and premium lifetime subscription available for single web domain. Basic subscription available for non-commercial websites at reduced cost.
3. Community Edition (Open Source): Community edition released under GNU AGPLv3 license, available free of charge for non-commercial use. Generates indirect revenue through community adoption and potential premium upgrade conversion.

Pricing tiers

Go-to-market motion1 record

Distribution channels4 records

Marketing channels5 records

Core offering

RainLoop Webmail is a PHP-based webmail client that provides modern IMAP/SMTP email access via any web browser, without requiring a database backend. It is offered in three editions: a free Community edition (AGPLv3) for non-commercial use, a paid Standard edition (commercial subscription) for commercial websites, and a deprecated Legacy edition (MIT). The product supports SSL/STARTTLS, OpenPGP encryption, 2FA, Sieve scripts, social login, and a plugin system for extensibility.

Product overview

RainLoop Webmail is a single, unified web-based email client product offered in three editions: Legacy (MIT License, deprecated v1.17.0), Community (AGPLv3, free for non-commercial use), and Standard (commercial subscription-based). The core product provides IMAP/SMTP connectivity, Sieve filtering, modern web UI, and plugin extensibility. Commercial editions add one-click updating and custom branding. The Standard edition is available via Basic (non-commercial), Premium one-year, and Premium lifetime subscription tiers.

Differentiator

Problem solved

Functional benefit

Brands

• RainLoop Webmail Legacy Edition: Released under MIT License, deprecated legacy version
• RainLoop Webmail Community Edition
• RainLoop Webmail Standard Edition

Products and services

• RainLoop Webmail Community Edition Free open-source web-based email client released under GNU AGPLv3 license for non-commercial websites. Provides IMAP/SMTP connectivity, modern browser UI, Sieve scripts, plugin extensibility, social login, OpenPGP encryption, and 2FA. Latest active branch in ongoing release line.
• RainLoop Webmail Standard Edition Commercial webmail client released under RainLoop Software License for commercial websites. Includes all Community edition features plus one-click updater and custom branding options. Requires a Basic, Premium one-year, or Premium lifetime subscription based on use case.
• RainLoop Webmail Legacy Edition Deprecated legacy version of the webmail client released under MIT License, with v1.17.0 as the final release. Provided for users on the historical MIT-licensed branch.

Segments3 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration4 records

Feature10 records

Recent moves6 records

Expansion highlights4 records

Market position

Strengths4 records

Competitive moat4 records

Key risks6 records

Key highlights5 records

Customer concentration

• GitHubgithub.com/RainLoop/rainloop-webmail

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Rainloop