Software Alternatives, Accelerators & Startups

CheckIO VS ForthWrite

Compare CheckIO VS ForthWrite and see what are their differences

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CheckIO logo CheckIO

CheckIO is a web site with a mission: To teach JavaScript and Python coding skills through a game-playing interface. It is designed to teach new skills or improve existing skills through completing challenges.

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
  • CheckIO Landing page
    Landing page //
    2021-09-16
  • 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.

CheckIO

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

CheckIO features and specs

  • Interactive Learning
    CheckIO provides an engaging and interactive way to learn programming concepts through solving coding challenges. This hands-on approach helps reinforce learning effectively.
  • Community Support
    The platform has a strong community where users can share solutions, get feedback, and learn from others' code. This collaborative environment can be very beneficial for learning and improving coding skills.
  • Variety of Challenges
    CheckIO offers a wide range of challenges that cater to different skill levels, allowing users to progress from basic to advanced problems. This variety keeps users engaged and continually learning.
  • Gamification
    The platform includes gamified elements such as points, badges, and leaderboards, which can increase motivation and make the learning process more enjoyable.
  • Python and JavaScript
    CheckIO supports both Python and JavaScript, making it versatile for learners who want to improve their skills in either of these popular programming languages.
  • Educational Missions
    The platform offers educational missions that are designed to teach specific programming concepts or algorithms, providing a focused learning experience.

Possible disadvantages of CheckIO

  • Limited Language Support
    CheckIO currently supports only Python and JavaScript, which may be a limitation for users looking to practice other programming languages.
  • Requires Internet Connection
    The platform is web-based, so a consistent internet connection is required to access challenges and content. This may be a drawback for users with limited or unreliable internet access.
  • Pacing and Difficulty
    Some users may find the difficulty of certain challenges to be either too high or too low, making it harder to find problems that are appropriately challenging for their skill level.
  • Limited Career Development Features
    The site focuses primarily on coding challenges and lacks extensive resources for job placement or career development compared to other platforms like HackerRank or LeetCode.
  • Less Comprehensive Tutorials
    While CheckIO provides educational missions, it may not be as comprehensive in tutorials and explanations compared to other dedicated learning platforms like Codecademy or Coursera.

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 CheckIO

Overall verdict

  • Yes, CheckIO is considered a good platform.

Why this product is good

  • CheckIO is praised for its engaging and interactive approach to learning programming. It offers a wide range of coding challenges that help users improve their coding skills in Python and JavaScript. The platform encourages problem-solving and critical thinking, providing immediate feedback and the opportunity to see how others have solved the same problem. It also has a community-driven aspect, allowing users to create and share their own challenges.

Recommended for

  • beginners looking to learn Python or JavaScript in an interactive way
  • developers who wish to practice and enhance their coding skills through challenges
  • programmers interested in joining a community of learners and creators
  • educators seeking supplemental material for teaching coding concepts

Analysis of ForthWrite

Overall verdict

  • I don't have verified information about a product called ForthWrite (forthwrite.ai). I cannot confirm its features, quality, or reputation, so I'm unable to provide an accurate assessment of whether it's good.

Why this product is good

  • No reliable data available on this specific product in my knowledge base
  • This may be a newer product, a niche tool, or possibly a fictional/hypothetical name
  • Providing details without verified information could result in inaccurate or fabricated claims

Recommended for

  • Unable to determine without verified product information
  • Consider checking the official website, user reviews on platforms like G2 or Trustpilot, and independent tech review sites for accurate details

CheckIO videos

Intro Video. How to get maximum from CheckiO

ForthWrite videos

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

Add video

Category Popularity

0-100% (relative to CheckIO and ForthWrite)
Online Learning
100 100%
0% 0
Writing Tools
0 0%
100% 100
Online Education
100 100%
0% 0
Email
0 0%
100% 100

Questions & Answers

As answered by people managing CheckIO 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 CheckIO 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 CheckIO and ForthWrite

CheckIO Reviews

15 Best LeetCode Alternatives 2023
CheckiO is a platform with coding games created for different levels of programmers, from beginners to advanced levels. Using fun and engaging methods, you can use coding games to solve challenges in TypeScript and Python on the platform.
8 Best LeetCode Alternatives and Similar Platforms
CheckIO is available in English and Spanish. The platform was designed by a group of engineers and now has a number of customers all over the globe who may use it to improve their programming speed and abilities by following the instructions on the screen.
4 high-quality HackerRank alternatives (plus 7 honorable mentions)
Checkio is the most whimsical HackerRank alternative on this list. Itโ€™s also focused on two languages: Python and TypeScript. On this site youโ€™ll be thrown into a gamerโ€™s paradise that includes robot mollusks and coding your way off an island. But once you accept the coding challenges, you go straight into a serious coding environment.

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, CheckIO seems to be more popular. It has been mentiond 46 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.

CheckIO mentions (46)

  • I am stuck!
    Have you heard of CheckIO (https://checkio.org/)? They have a gameified "Mario world" of coding challenges that are smaller and come with more explanation, tests to guide you through edge cases and provide hints. The challenges start from total beginner and progress to more advanced. And best of all, after you solve a problem they show you what other people do. I highly recommend this for you. Also consider... Source: over 2 years ago
  • I feel like I may not be smart enough to get into the cybersecurity space
    Cyber isn't gonna be a light switch, where you can flip it and be good. Don't be too hard on yourself. Start with some hands on stuff like https://tryhackme.com or checkio.org. You could look at certs like Security+ or CySA+ for some direction. It took me years to get into cybersecurity, and I still don't feel like I know anything. Source: about 3 years ago
  • I need some advice to learn Python.
    Much better to get your hands dirty than watching the videos. Try: https://checkio.org/. Source: about 3 years ago
  • Where can i test my knowledge?
    When I was first learning python I like using https://checkio.org/ Checkio provides programming problems in a gamified environment. After you have solved a problem you can see how others have solved the problem. This really accelerated my learning. Source: about 3 years ago
  • Projects for beginners
    Look at checkio.org. Range of problems to solve ('missions') When you do you can see how others solved them too which ids very instructive. 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 CheckIO and ForthWrite, you can also consider the following products

Codewars - Achieve code mastery through challenge.

Superhuman - Superhuman is an email management tool.

Exercism - Download and solve practice problems in over 30 different languages.

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.

CodeCombat - Learn programming with a multiplayer live coding strategy game.

Lavender - Realtime coaching for sales emails.