Software Alternatives, Accelerators & Startups

Zimbra VS ForthWrite

Compare Zimbra VS ForthWrite and see what are their differences

Zimbra logo Zimbra

Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.

ForthWrite logo ForthWrite

Email that sounds like you, and gets measurably more like you every week. Drafts in Gmail, Outlook, and the browser. Free to start.
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  • Zimbra Landing page
    Landing page //
    2023-05-06

Zimbra is the trusted email and collaboration platform and productivity suite that includes contacts, calendar, tasks, chat and file sharing, plus videoconferencing, document editing, and file storage. Built on an open source core, it features a modern interface, pre-integrations with popular third-party apps like Zoom, Slack and Dropbox, and can be deployed in the cloud or in on-prem and hybrid environments. Enterprises, governments, financial institutions, service providers and remote teams around the world rely on Zimbra to support complex privacy, data sovereignty and security requirements. Today, Zimbra powers hundreds of millions of mailboxes on desktop and mobile devices in more than 140 countries, and is offered by more than 500 BSPs and 2,000 channel partners. Also available now for small and medium-sized business is Zimbra Cloud, starting at $2.95 per month for 30 GB of storage. Visit www.zimbra.com to learn more and begin a free trial.

  • ForthWrite Landing Page
    Landing Page //
    2026-06-19
  • ForthWrite Dashboard
    Dashboard //
    2026-06-19
  • ForthWrite In Gmail
    In Gmail //
    2026-06-19
  • ForthWrite Pricing
    Pricing //
    2026-06-19

ForthWrite is an AI email writing assistant for Gmail and Outlook that learns your writing style from your real sent mail. The more you use it, the more it sounds like you. Get smart drafts in seconds, auto-draft replies before you open your inbox, and maintain your personal voice at scale. Free to start, no credit card required. Works inside Gmail and Outlook on the web.

How it works

ForthWrite captures your tone, sentence rhythm, and sign-offs from your actual sent emails, then uses that profile to generate drafts that match how you write, not a generic AI voice. Every draft you edit or send improves the model over time.

Key features

  • Auto-draft: replies waiting in Gmail before you open your inbox
  • Voice matching from your real sent mail, not templates
  • Recipient-aware drafts that adapt to who you are emailing
  • Prompt Lab for version-controlling and A/B testing your persona prompt
  • BYOK support: bring your own API key for Claude, OpenAI, Grok, Mistral, and more
  • Works in Gmail and Outlook on the web, plus a standalone browser widget
  • Training data export and full data portability

Who uses it

Professionals who send high volumes of relationship-critical email: lawyers, financial advisors, recruiters, account executives, founders, and anyone who wants their inbox handled without sounding like a chatbot wrote it.

Pricing

Free tier includes 10 drafts per week with no credit card required. Paid plans start at $12/month and include unlimited drafts, custom persona prompts, and auto-draft.

Zimbra

Website
zimbra.com
Pricing URL
-
$ Details
-
Platforms
-
Release Date
-

ForthWrite

$ Details
freemium $12.0 / Monthly (Standard plan)
Platforms
Web
Release Date
2026 June
Startup details
Country
United States
State
California
City
San Diego
Founder(s)
Curtis Boortz
Employees
1 - 9

Zimbra features and specs

  • Open Source
    Zimbra offers an open-source solution for email, calendar, and collaboration tools, allowing users to modify and customize the software according to their needs.
  • Cost-Effective
    Zimbra can be a more affordable option compared to proprietary email solutions, especially for small and mid-sized businesses.
  • Scalability
    Zimbra is capable of scaling to meet the needs of both small businesses and large enterprises, making it a versatile option for organizations of different sizes.
  • Feature-Rich
    Zimbra includes a wide range of features such as email, calendar, contacts, task management, and file sharing, which can enhance productivity and collaboration.
  • Cross-Platform Support
    Zimbra supports various platforms including Windows, Mac, and Linux, and offers web-based access, which enhances its accessibility.
  • Integration Capabilities
    Zimbra can integrate with other enterprise applications and services, including Microsoft Outlook, enhancing its utility within an existing IT infrastructure.

Possible disadvantages of Zimbra

  • Complex Installation and Maintenance
    Setting up and maintaining Zimbra requires a certain level of technical expertise, which can be a barrier for organizations without dedicated IT staff.
  • Resource Intensive
    Zimbra can be resource-intensive, requiring significant server resources to run effectively, which can be a drawback for organizations with limited IT infrastructure.
  • Limited Support
    While community support is available, the extent and quality can be inconsistent. Paid support options are available but add to the overall cost.
  • Learning Curve
    The wide range of features and customization options in Zimbra can result in a steep learning curve for new users, which may impact initial productivity.
  • Occasional Performance Issues
    Some users have reported experiencing performance issues with Zimbra, particularly when handling large volumes of emails or during peak usage times.
  • Compatibility Issues
    Although Zimbra supports integration, there can be compatibility issues with certain third-party applications or specific versions of software, which might require additional troubleshooting.

ForthWrite features and specs

  • Voice Matching
    Learns from your real sent mail, not templates
  • Auto-draft replies
    Replies waiting in Gmail before you open your inbox
  • Batch-drafting
    Draft replies for your entire inbox with one click
  • Works in browser
    Gmail, Outlook, and web browsers
  • BYOK support
    Claude, OpenAI, Grok, Mistral, and more
  • Prompt Lab
    Version control and A/B test your persona prompt
  • Free tier
    10 drafts per week, no credit card required

Analysis of Zimbra

Overall verdict

  • Zimbra is generally considered a good choice for businesses and educational institutions seeking a reliable email server solution with strong collaboration tools. Its versatility, security features, and scalability make it suitable for various organizational needs.

Why this product is good

  • Zimbra is known for its robust set of email server features, including support for both web-based and desktop email clients, calendar and address book integration, and strong security features. It also offers good customization options, scalability, and is available with open-source options, which makes it an attractive choice for both small and large organizations. Additionally, Zimbra provides mobile access and collaboration tools, which enhance productivity.

Recommended for

    Zimbra is recommended for businesses, educational institutions, and non-profit organizations that require a comprehensive email and collaboration platform. It's particularly suitable for those who need customization options and value open-source solutions. It can be an excellent fit for IT departments seeking to manage their own email infrastructure rather than relying on third-party service providers.

Zimbra videos

Modern Collaboration: Discover why Zimbra is the open source leader in Email and Collaboration

More videos:

  • Review - Zimbra #01 introduction of Open Source Email Collaboration Solution
  • Review - Zimbra Review: Why The University of Pennsylvania Likes Zimbra Email?

ForthWrite videos

No ForthWrite videos yet. You could help us improve this page by suggesting one.

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Category Popularity

0-100% (relative to Zimbra and ForthWrite)
Email
95 95%
5% 5
Writing Tools
0 0%
100% 100
Email Clients
100 100%
0% 0
Calendar
100 100%
0% 0

Questions & Answers

As answered by people managing Zimbra and ForthWrite.

Which are the primary technologies used for building your product?

ForthWrite's answer:

Next.js, React, Supabase, Anthropic Claude, OpenAI, Stripe, Vercel, Chrome Extensions API

What makes your product unique?

ForthWrite's answer:

ForthWrite learns your writing style from your actual sent mail, not a generic prompt. Every draft sounds like you wrote it because it was trained on how you actually write. It also auto-drafts replies before you open your inbox, so your email is partially handled before your day starts.

Why should a person choose your product over its competitors?

ForthWrite's answer:

Most AI email tools give you a blank box and a "write for me" button. ForthWrite builds a voice profile from your sent history and gets more accurate with every draft you edit or send. Unlike ChatGPT or Gemini, it works natively inside Gmail and Outlook with no copy-paste. Unlike Lavender, it writes the draft, not just scores it.

How would you describe the primary audience of your product?

ForthWrite's answer:

Professionals who send high volumes of relationship-critical email and cannot afford to sound generic: lawyers, financial advisors, recruiters, account executives, consultants, and founders managing their own inbox.

What's the story behind your product?

ForthWrite's answer:

Built out of frustration with AI writing tools that produce text that sounds nothing like the person sending it, and as a way to handle large amounts of daily email. The core insight was that your sent mail is the best training data you already have, and no tool was using it.

User comments

Share your experience with using Zimbra and ForthWrite. For example, how are they different and which one is better?
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Reviews

These are some of the external sources and on-site user reviews we've used to compare Zimbra and ForthWrite

Zimbra Reviews

Alternative to Zimbra - atmail versus Zimbra - email for telcos
If youโ€™re tired of Zimbra email, talk to us instead. We have more than 20 years of global email expertise and power 170 million mailboxes worldwide. We can be trusted to keep your platform secure, stable, scalable and private. Our modern, white label, multitenant and monetisable solutions are available both on-premises and in the cloud. We also wonโ€™t make you go through a...
Source: www.atmail.com
Overview of 5 Best Microsoft Exchange Server Alternatives
If you are an enterprise-level company that is looking for a solution based on open-source technologies, then Zimbra might be what you are looking for. As per the team behind Zimbra, this collaboration platform encompasses multiple open source projects under one supported and certified open-source collaboration application tailored to satisfy the needs of enterprises.
Source: jatheon.com
15 Best iRedMail Alternatives 2021
Zimbra has a calendar feature like iRedMail with a simple web and mobile UI that lets you manage your calendars and address books. Similarly, it also supports POP, IMAP, CardDAV, and CalDAV protocols.
Top 10 Webmail Clients in 2021
Zimbra Zimbra also works in web browsers. But it isnโ€™t like PHP web clients as it uses the AJAX set of web technologies instead. It offers email and calendar functionality and you can view messages and conversation formats. Its approach to visual search is particularly effective in making short work of managing the largest inboxes. Zimbra is one of the open-source webmail...
Source: www.plesk.com
5 open source webmail clients for browser-based email
Zimbra is a well-maintained project that has been hosted at a number of different corporate entities through the years, and was acquired by Synacore in 2016. It features most of the things you've come to expect in a modern webmail client, from webmail to folders to contact lists to a number of pluggable extensions, and generally works very well. I have to admit that I'm most...
Source: opensource.com

ForthWrite Reviews

  1. curtisboortz
    ยท Founder at ForthWrite ยท
    I built ForthWrite to fix generic AI email, and I still use it every day

    I built ForthWrite because I kept sending emails that sounded like they came from the same generic AI as everyone else. After launching it, I still use it for my own inbox every day, which is about the most honest endorsement I can give.

    The Chrome extension lives inside Gmail and Outlook on the web. Open a thread, hit Alt+Shift+D, and a draft comes back in your voice, not a template. The free tier is real: 10 drafts per week, no API key, no credit card. Voice matching is included on free, because that is the point.

    What keeps it useful compared to Gemini or a chat tab: it learns from what you actually send. Every edit you make before hitting send becomes a signal. Over time the drafts drift closer to how you really write, and the dashboard shows the improvement curve so you can see it happening.

    The web compose surface lets you draft from forthwrite.ai without installing anything, useful for people who want to try before committing to the extension.

    Standard adds recipient-aware and intent-aware drafting plus AI coaching. Pro adds auto-draft (replies waiting when you open Gmail), batch replies, and Prompt Lab for version-controlling your prompts. Teams adds a shared persona and seat-level analytics.

    ForthWrite is not for everyone. If you just need quick replies and tone does not matter, Gemini is free and already in your inbox. ForthWrite is for people where tone does matter: client communication, relationship-driven threads, external correspondence where sounding off costs something real.

    Disclosure: I am the founder and use it daily. Happy to answer questions in the comments.

    ๐Ÿ Competitors: Jace.ai, Fyxer, Mailmeteor
    ๐Ÿ‘ Pros:    Drafts land inside gmail and outlook; no copy-pasting from a chat window|Voice matching is on the free tier, not paywalled behind paid plans|No api key, no credit card to start; free tier runs on a server-side proxy|Learns from every edit you make before sending; drafts improve over time|Full keyboard flow: alt+shift+d to draft in any thread, no mouse required|Byok on paid plans, 9 providers supported, keys encrypted at rest|Web compose at forthwrite.ai works without installing the extension at all
    ๐Ÿ‘Ž Cons:    10 free drafts/week is enough to evaluate, not enough for a heavy inbox|Auto-draft, batch replies, and prompt lab all require the pro tier|Early-stage product; fewer third-party integrations than mature inbox tools|No mobile app: the extension and add-in are desktop-only (chrome on web, or the outlook desktop add-in)

What are some alternatives?

When comparing Zimbra and ForthWrite, you can also consider the following products

Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!

Superhuman - Superhuman is an email management tool.

Roundcube - Web-based IMAP email client

Gemini - Gemini, formerly known as Bard, is a generative artificial intelligence chatbot developed by Google. Based on the large language model (LLM) of the same name, it was launched in 2023 in response to the rise of OpenAI's ChatGPT.

Google Workspace - Google's encompassing suite of cloud-based business apps.

Lavender - Realtime coaching for sales emails.