Software Alternatives, Accelerators & Startups

Spark Mail VS ForthWrite

Compare Spark Mail VS ForthWrite and see what are their differences

Spark Mail logo Spark Mail

Spark helps you take your inbox under control. Instantly see whatโ€™s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues

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
  • Spark Mail Landing page
    Landing page //
    2023-07-22
  • 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.

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

Spark Mail features and specs

  • Smart Inbox
    Spark Mail intelligently categorizes emails into Personal, Notifications, and Newsletters, making it easy to prioritize your important messages and reduce clutter.
  • Collaborative Email
    Allows teams to discuss emails privately, share drafts, and collaborate on responses in real-time, improving team productivity and communication.
  • Customization
    Provides extensive customization options, enabling users to tweak the interface, swipe actions, and notification settings according to their preferences.
  • Unified Inbox
    Combines all your email accounts into a single inbox, simplifying email management for those with multiple email addresses.
  • Scheduled Sending
    Enables users to schedule emails to be sent later, making it easier to manage communication across different time zones.
  • Smart Search
    Offers advanced search functionality to quickly find emails using natural language queries and filters.

Possible disadvantages of Spark Mail

  • Privacy Concerns
    Some users have raised concerns about the data Spark Mail collects and how it handles user privacy, despite the company's assurances.
  • Subscription Model
    While the basic version is free, some advanced features are locked behind a subscription, which might be a deterrent for some users.
  • Limited Integrations
    Compared to some competitors, Spark Mail offers fewer integrations with third-party apps and services, which can be limiting for advanced users.
  • Occasional Bugs
    Users have reported occasional bugs and performance issues, which can cause inconvenience and affect productivity.
  • Team Features Complexity
    The collaborative features, while powerful, can be complex to set up and use effectively, posing a steep learning curve for new users or non-technical teams.
  • Platform Limitations
    Available mainly on Apple platforms and limited support for Windows and Android devices, restricting accessibility for some users.

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

Spark Mail videos

Should You Buy the New Positive Grid Spark Amp? | Review + Demo

More videos:

  • Review - DJI SPARK IN-DEPTH REVIEW!! (4K)
  • Review - 2020 Chevrolet Spark Review | Nimble w/Tons of Value

ForthWrite videos

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

Add video

Category Popularity

0-100% (relative to Spark Mail and ForthWrite)
Email
98 98%
2% 2
Writing Tools
0 0%
100% 100
Email Clients
100 100%
0% 0
Calendar
100 100%
0% 0

Questions & Answers

As answered by people managing Spark Mail 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 Spark Mail 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 Spark Mail and ForthWrite

Spark Mail Reviews

10 Best Alternatives to Microsoft Outlook to Try in 2023
Spark is a popular email client for Mac that offers a number of features that make it a great alternative to Outlook. One of the biggest advantages of Spark is its user-friendly interface. It's easy to navigate and has a clean, modern design that makes it easy to read and compose emails.
Source: mysignature.io
11 Top Outlook Alternatives to Try
Not every user is thrilled with Sparkโ€™s privacy practices. For example, once youโ€™ve set up your email accounts on one device, youโ€™ll never have to enter all of your passwords or other details again. When you install Spark on another device, you enter the details of one of the accounts, and all of your inboxes are automatically synced.
Source: kinsta.com
10 BEST Outlook Alternatives in 2023
Spark is a software package that automatically categorizes emails for secure processing. It is one of the best Outlook alternative that allows you to pin or snooze emails. You can invite your teammates to create mail together.
Source: www.guru99.com
10 Alternatives to Thunderbird Reddit โ€“ Ease Your Email Life!
In search of something better, I started using Airmail again after quite some time. Now I understand that Airmail is still one of the easiest and best ways to do all that we need to do. With Spark, you can navigate through your email with a minimal interface. Finally, thereโ€™s MailMate, an email client with more power than any other for Mac OS- though the company charges for...
Source: droidpile.com
11 Best Thunderbird Alternatives That Make Email Easier
Here you can access most of Sparkโ€™s planned features as swipe actions, unique inbox, snooze, and save for future use. Also, you can get the modern features of Thunderbird which include rules, email filtering, and large search criteria.

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, Spark Mail seems to be more popular. It has been mentiond 32 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.

Spark Mail mentions (32)

  • 12 Developer Tools That Keep My Workflow Smooth
    Email is usually a productivity killer. Spark Mail makes it manageable and keeps my inbox sane. - Source: dev.to / 9 months ago
  • macOS Tahoe
    I can't seem to select any text on your website so had to go screenshot, then select. But: > All your devices, synced > Mac, Windows, iOS, Android-stay in sync across all platforms. Does this mean email is managed on a server like Spark[1]? [1] https://sparkmailapp.com. - Source: Hacker News / 10 months ago
  • My ADHD Life Pro tips
    Using https://sparkmailapp.com/ for email, where I put in all my email IDs and make it a ritual to finish all email in one go once in the day, I habit bundle the email with coffee always. Source: over 2 years ago
  • How integrated into the Apple software ecosystem are you?
    Regarding email, I find the Mail app to be adequate for most purposes. However, I do prefer Mimestream on Mac and Spark on iOS for their user interface. Specifically, I find Spark on Mac to be a bit heavy. It is worth noting that I use custom domain email hosted through Apple instead of Gmail. Source: about 3 years ago
  • Poor time management
    Apps like Notion,Forest, Veamly orSpark can be useful. Source: about 3 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 Spark Mail and ForthWrite, you can also consider the following products

Superhuman - Superhuman is an email management tool.

Gmail - Gmail is available across all your devices Android, iOS, and desktop devices. Sort, collaborate or call a friend without leaving your inbox.

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.

Microsoft Outlook - Organize your world. Outlookโ€™s email and calendar tools help you communicate, stay on top of what matters, and get things done.

Lavender - Realtime coaching for sales emails.

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