Software Alternatives, Accelerators & Startups

Penzu VS ForthWrite

Compare Penzu VS ForthWrite and see what are their differences

Note: These products don't have any matching categories. If you think this is a mistake, please edit the details of one of the products and suggest appropriate categories.

Penzu logo Penzu

Keep all of your thoughts in one place using Penzu. The app is similar to a journal that you might write in but with a few modern touches that allow you to do everything from sending messages to decorating the pages.

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.
Visit Website
  • Penzu Landing page
    Landing page //
    2021-09-13
  • 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.

Penzu

Website
penzu.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

Penzu features and specs

  • Privacy
    Penzu offers highly secure writing with password-protected journals and military-grade 256-bit encryption, ensuring that your personal thoughts remain private.
  • Customization
    Users can customize their journal entries with different fonts, themes, and formatting options, allowing for a personalized journaling experience.
  • Accessibility
    Penzu is available on multiple platforms including web, iOS, and Android, making it easy to access your journal from anywhere.
  • Reminders
    The app allows users to set reminders to journal regularly, helping to build a consistent writing habit.
  • Search Functionality
    Users can search their journal entries by keyword, making it easy to find specific entries or topics.

Possible disadvantages of Penzu

  • Cost
    Many of the advanced features, such as encryption and customization, require a paid subscription, which may be a barrier for some users.
  • Complexity
    The wide range of features and customization options can make the app overwhelming for new users.
  • Offline Access
    Offline functionality is limited, meaning users need an internet connection to access all features and sync entries across devices.
  • Exporting Data
    Exporting journal entries to other formats is not as straightforward or integrated as some users might prefer.
  • Learning Curve
    New users might require some time to learn how to effectively use all the features, especially if they are not tech-savvy.

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 Penzu

Overall verdict

  • Penzu is a good choice for individuals seeking a straightforward, flexible, and private journaling tool. Its emphasis on privacy and user-friendly design makes it suitable for both casual and serious journal keepers. However, users who require advanced features like integration with other tools or extensive formatting options might find Penzu somewhat limited.

Why this product is good

  • Penzu is an online journaling platform that provides a secure and private way to keep a journal. It is praised for its simplicity, ease of use, and the ability to access your entries from any internet-connected device. Penzu also has features like customizable covers, the ability to add images, and reminders to help users maintain a regular journaling habit. Additionally, Penzu offers strong privacy options, including the ability to password-protect individual entries or the entire journal, making it appealing to those who value confidentiality in their writing.

Recommended for

    Penzu is recommended for users who value privacy in their journaling, prefer a simple and straightforward user interface, and want a digital platform that allows easy access across multiple devices. It's particularly suited for individuals who are keen on maintaining a consistent journaling practice without the need for complex features.

Penzu videos

Penzu How It Works

More videos:

  • Review - Using Penzu for Reflection in Teaching

ForthWrite videos

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

Add video

Category Popularity

0-100% (relative to Penzu and ForthWrite)
Note Taking
100 100%
0% 0
Writing Tools
0 0%
100% 100
Journal
100 100%
0% 0
Email
0 0%
100% 100

Questions & Answers

As answered by people managing Penzu 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 Penzu 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 Penzu and ForthWrite

Penzu Reviews

The 8 best journal apps of 2022
Writing a journal entry in Penzu is much like writing a blog post in WordPress, with a WYSIWYG (What You See Is What You Get) interface, complete with a text formatting toolbar. So why not just use Word, WordPress, or a note-taking app like Evernote? For one thing, Penzu keeps your entries together in one journal online, as opposed to several different files. Custom email...
Source: zapier.com
5 Best Apps That Make Journaling Super Convenient In 2022
If youโ€™re looking for security for a more private journal, then Penzu is your best bet. Whether youโ€™re keeping a bullet journal, dream journal, or youโ€™re looking for a food journal app, this has a straightforward user interface that allows you to customize and record your thoughts while keeping them secure from prying eyes.
Source: integrately.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)

Social recommendations and mentions

Based on our record, Penzu seems to be more popular. It has been mentiond 1 time since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

Penzu mentions (1)

  • How to Leave an Abusive Relationship
    - Penzu is an online journal site that can only be accessed with the proper password. Keep a record of abuse on Penzu, and wipe all mention of the site from your browser history. Source: over 3 years ago

ForthWrite mentions (0)

We have not tracked any mentions of ForthWrite yet. Tracking of ForthWrite recommendations started around Jun 2026.

What are some alternatives?

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

Day One - A simple journal application for the Mac, iPhone, and iPad. AboutTo learn more about Day One, see these two excellent reviews . PublishPublish is not available in Day One 2.

Superhuman - Superhuman is an email management tool.

RedNotebook - RedNotebook is a software that format, tag and search entries and add pictures, links and customizable templates, spell check notes, and export to plain text, HTML, Latex or PDF.

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.

Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.

Lavender - Realtime coaching for sales emails.