Google Open Source VS ForthWrite

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.

Questions & Answers

As answered by people managing Google Open Source 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.

Reviews

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

Google Open Source Reviews

We have no reviews of Google Open Source yet.
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ForthWrite Reviews

curtisboortz

· Founder at ForthWrite · 28 days ago

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.

🏁 Competitors: Jace.ai, Fyxer, Mailmeteor

👍 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

👎 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, Google Open Source seems to be more popular. It has been mentiond 26 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.

Google Open Source mentions (26)

How I Got Into Google Summer of Code (GSoC) 2026 as a Tier-3 MCA Student
Google Summer of Code (GSoC) is a global program run by Google where students and open source beginners get paid to contribute to open source organizations over a summer. You apply to a specific organization with a project proposal, a mentor reviews it, Google funds the selected contributors, and you spend the coding period working on real software used by real people. It's not an internship at Google — the org... - Source: dev.to / 2 months ago
Sustainable Funding for Open Source: Navigating Challenges and Emerging Innovations
Many companies that depend on OSS contribute financially so that the projects remain robust. Examples like Google and Microsoft have shown that corporate sponsorship is not only beneficial for maintainers but also for companies that rely on reliable software. The corporate sponsorship model moves away from traditional ad-based revenue generation, fostering a direct relationship between the sponsor and the... - Source: dev.to / about 1 year ago
Revolutionizing Blockchain and Open Source Funding: Microfunding and Project Funding Alternatives – A Comprehensive Guide
Similarly, open source projects, which are the backbone of digital infrastructure, have long struggled to achieve sustainable funding. Crowdfunding platforms such as Kickstarter, Opencollective, and corporate sponsorships from technology giants like Google’s open source initiatives and Microsoft’s commitment to open source are now offering viable alternatives. Innovators have begun to integrate Non-Fungible Tokens... - Source: dev.to / about 1 year ago
Funding Open Source Innovation: Empowering Sustainable Maintenance and Development
Governments, academic institutions, and major tech companies like Microsoft and Google have recognized the importance of financial support. Funding models have evolved to include corporate sponsorships, grants (e.g., Mozilla's Open Source Support Program), and community-driven donations through platforms like GitHub Sponsors and Open Collective. - Source: dev.to / about 1 year ago
Revolutionizing Blockchain and Open Source Funding: Microfunding and Project Funding Alternatives
Sponsorship Programs: Platforms such as GitHub Sponsors and offerings from tech giants like Google Open Source and Microsoft Open Source provide recurring support while maintaining community values. - Source: dev.to / over 1 year ago

ForthWrite mentions (0)

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

curtisboortz

· Founder at ForthWrite · 28 days ago

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.

🏁 Competitors: Jace.ai, Fyxer, Mailmeteor

👍 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

👎 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)

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