Software Alternatives, Accelerators & Startups

Lightspark VS ForthWrite

Compare Lightspark 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.

Lightspark logo Lightspark

The Lightspark project

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
  • Lightspark Landing page
    Landing page //
    2021-10-02
  • 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.

Lightspark

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

Lightspark features and specs

  • Open Source
    Lightspark is an open-source project which means its source code is freely available, allowing developers to inspect, modify, and contribute to its development.
  • Cross-Platform Compatibility
    It is designed to work across multiple platforms, including Linux and Windows, providing flexibility and accessibility for various users.
  • Active Development
    The project is actively maintained, ensuring that it receives regular updates and bug fixes, which contribute to improving performance and stability.

Possible disadvantages of Lightspark

  • Limited Flash Support
    Lightspark focuses on supporting newer versions of Flash, which may not cover all the features of legacy Flash content, potentially limiting its effectiveness in certain situations.
  • Performance Issues
    Users may experience performance issues, such as slower playback and higher resource consumption, depending on their system configuration and the complexity of the Flash content.
  • Compatibility Gaps
    There may be compatibility gaps with some Flash content, as not all features and use cases are fully supported, leading to inconsistent user experiences.

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

Category Popularity

0-100% (relative to Lightspark and ForthWrite)
Online Services
100 100%
0% 0
Writing Tools
0 0%
100% 100
Product Presentation
100 100%
0% 0
Email
0 0%
100% 100

Questions & Answers

As answered by people managing Lightspark 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 Lightspark 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 Lightspark and ForthWrite

Lightspark Reviews

We have no reviews of Lightspark yet.
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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, Lightspark seems to be more popular. It has been mentiond 9 times 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.

Lightspark mentions (9)

  • When SVG almost got network support for raw sockets
    Not the first attempted Flash reimplementation[1,2,3]. The GNU one didnโ€™t work all that well back in the day as far as I remember, but then Flash was a moving target at the time. [1]: https://www.gnu.org/software/gnash/ [2]: http://lightspark.github.io/ [3]: https://github.com/mozilla/shumway. - Source: Hacker News / over 3 years ago
  • Good flash emulator for walfas?
    A true emulator would be something like Ruffle or Lightspark. Ruffle I know doesn't work well with Walfas last time I checked. I don't know about Lightspark. Source: almost 4 years ago
  • Flash game to Html5 converter
    Lightspark, a browser plugin written in C++. It's a work in progress, not every flash content will work. Modern mainstream browsers don't support running it within a page, so flash content needs to be run in a standalone lightspark app, or in some lesser known browsers. Source: almost 4 years ago
  • How and where do I tell CMake where my C/CXX compiler is?
    I'm trying to install lightspark on my computer, and it hinges on launching a shell script that mainly executes a CMake command. When I try ./build.sh (the name of the shell script), I get a bunch of lines of errors. The first one I think is major is CMake Error at /usr/share/cmake-3.23/Modules/CMakeTestCCompiler.cmake:69 (message): The C compiler "/usr/bin/cc" is not able to compile a simple test... Source: about 4 years ago
  • What "legacy" software are you still forced to use in 2022 that you wish would die?
    I'm having alot of fun with this post actually. I wouldn't be surprised if there was some alternative or workaround for whatever you guys need to run. For example, instead of the clunky Java, we have this. Instead of Flash, try this. Source: over 4 years ago
View more

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 Lightspark and ForthWrite, you can also consider the following products

Ruffle - An open source Flash player

Superhuman - Superhuman is an email management tool.

Flash Player 2021 - Want to fix "This plugin is not supported" and "Adobe Flash Player is blocked" error messages? This extension will remove those messages and allow you to play Flash in any website with a single click.

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.

SuperNova Player - SuperNova Player allows systems to play .SWF files in a standalone player launched from any browser.

Lavender - Realtime coaching for sales emails.