Email tool comparison
ForthWrite vs Superhuman
Elite email client. Drafts are a feature, not the product.Here's where each tool wins, and where the depth-on-voice differentiator actually matters.
ForthWrite
A writing platform for people who care how their email reads. Voice matching on every tier; coaching dashboard on Standard+; auto-draft, batch, and Prompt Lab on Pro. 9-provider BYOK.
Where we win
- Edit capture on every tier; coaching dashboard on Standard+; RAG injection on Pro
- Measurable improvement curve on the dashboard (Standard+)
- 9-provider BYOK on Standard and Pro
- Standalone web compose surface in the browser
- Free tier includes voice matching (not just basic drafting)
Pricing: Standard $18/mo, Pro $36/mo. BYOK saves ~17%.
Best for: Professionals who want their email to keep sounding like them - and want to see the improvement curve.
Superhuman
Premium email client with split-inbox, snippets, scheduled send, and AI Instant Reply layered on top. No free plan; individual plan starts at $30/mo, Business plan at $40/user/month.
Where they win
- Best-in-class email client UX with 100+ keyboard shortcuts for fast email processing
- Mature shortcuts, snippets, scheduled send, split inbox
- Drafts in your "voice and tone" using inbox, calendar, web, and uploaded knowledge
- Highly rated iOS and Android mobile apps - clear advantage for mobile-first workflows
- Strong brand and existing premium customer base
What they don't do (or charge extra for)
- You have to switch email clients - Superhuman is the inbox, not a layer on top of Gmail or Outlook
- Onboarding requires a scheduled tutorial call
- Single-provider AI; no BYOK or model choice
- No edit capture, improvement coaching dashboard, or measurable voice-improvement curve
- No free plan - 14-day trial only, then $30/mo with no ongoing free tier
- No true shared inbox; designed for individual inbox management rather than support or sales team collaboration
Pricing: $30/mo individual; $40/user/month Business plan. No free version - 14-day free trial only (as of 2026).
Best for: Individual power users who want a premium email client with keyboard-first speed and AI as one of many features, and are willing to switch away from Gmail or Outlook to get the full package.
Head-to-head
The product-behavior comparison, not the marketing-page comparison.
All tiers capture draft-vs-sent pairs. Standard+ unlocks the improvement dashboard. Pro injects edit examples at generation time.
Superhuman wins this row. If raw speed via keyboard is the primary need, Superhuman is the better fit.
Superhuman wins on mobile. ForthWrite is desktop-only via Chrome.
ForthWrite doesn't ask you to switch clients - and goes deeper on voice fidelity.
Superhuman is a premium email client. ForthWrite is a voice system that lives inside the client you already use - Gmail or Outlook Web - without asking you to switch. If you love Gmail's interface and don't want to rebuild muscle memory for a new tool, that is the first difference: Superhuman makes you switch; ForthWrite doesn't. Superhuman is mainly built for individual inbox management, while team collaboration usually requires a shared inbox and team features that Superhuman does not offer.
On voice depth and learning loop: Superhuman writes drafts in your "voice and tone" using inbox, calendar, web, and uploaded knowledge. That is a one-shot synthesis at draft time. ForthWrite runs a closed loop - every AI draft is compared to what you actually sent, the gap becomes a training signal, the voice profile regenerates every ~50 captured sends, and the dashboard shows the improvement curve. One is a claim; the other is a measurement you can track.
On model choice: ForthWrite Standard and Pro ship with 9-provider BYOK so you can route different emails to different models. Superhuman gives you their model with no published model-choice feature.
Coexistence note: ForthWrite works inside Superhuman's Gmail-based client too if you have already paid for Superhuman. The extension layers onto Gmail-based workflows rather than replacing the email provider. You get Superhuman's keyboard workflow, split inbox, and snippets alongside ForthWrite's voice-matched drafts. You do not have to pick.
On switching cost: Superhuman's keyboard shortcuts and command palette are powerful once you have the muscle memory, but that muscle memory takes weeks to build. ForthWrite does not ask you to switch clients. If you are on Gmail, stay on Gmail. If you are on Outlook, stay on Outlook. The voice-matched drafting layer adds on top of whichever client you already know - zero switching cost, no inbox rebuild, no learning curve on shortcuts. Its desktop app speed can be a real advantage for power users, but the switching cost still matters if your actual workflow already lives in Gmail or Microsoft Outlook.
On team collaboration: Superhuman lacks true shared inbox functionality and is designed for individual inbox management only. If your workflow depends on shared inboxes, internal comments within email threads, or email assignment for support and sales teams, Missive is often the better fit among Superhuman alternatives - it supports shared inboxes, internal chat within email threads, and email assignment to specific team members.
What ForthWrite is not: a replacement for Superhuman's client-level features. If you need comprehensive keyboard shortcuts, a command palette, follow-up reminders, read receipts, auto-archive rules, multiple IMAP providers in a unified inbox, or best-in-class mobile apps for iOS and Android, Superhuman is the right product for those use cases, especially for individual inbox management. ForthWrite's advantage is specific to drafting: the emails it generates sound like you wrote them, and that match improves with every send. If voice-matched drafting quality is the primary thing you are evaluating, that is the distinction.
Frequently asked questions
Do I have to switch email clients to use ForthWrite?
No. ForthWrite is a browser extension and email plugin that works inside your current email app - Gmail, Outlook Web, or even Superhuman's Gmail-based interface directly in the browser. You manage incoming emails without switching clients or changing your email provider; you simply add a drafting layer on top.
Can I use ForthWrite and Superhuman at the same time?
Yes. ForthWrite's extension works inside Superhuman's Gmail-based client. Superhuman's desktop app stays exactly as it is while ForthWrite layers on top. You get Superhuman's keyboard workflow, split inbox, snippets, and Google Calendar context alongside ForthWrite's voice-matched drafts. You do not have to choose between them.
Does Superhuman learn my writing style over time?
Superhuman's AI Instant Reply generates drafts in your 'voice and tone' using your inbox, calendar, web, and uploaded knowledge as context - competitors often package this as Auto Drafts or Auto Summarize. That is still draft-time generation rather than a learning loop. ForthWrite runs a closed loop: every draft is compared to what you actually sent, the gap becomes a training signal, and the voice profile rebuilds every ~50 captured sends, so the AI improves measurably over time. One is a claim; the other is a measurement you can track on the dashboard. Inbox Zero also offers AI-powered reply drafts that learn your writing style.
Is ForthWrite cheaper than Superhuman?
ForthWrite's free tier includes 10 drafts per week with voice matching - no credit card required. ForthWrite Standard is $18/mo and Pro is $36/mo. Superhuman is $30/mo individual and $40/user/month Business with no free plan. Among the cheapest Superhuman alternatives: Mailman starts at $8/month (21-day free trial); Inbox Zero's Starter plan is $18/user/month; Shortwave is free to start with paid plans from $24/month; Missive offers a free plan and starts at $14/user/month. Mailbird offers a one-time $39.99 lifetime license. If you want voice-matched drafting without a premium email client, ForthWrite is the lower-cost path. If you want the full Superhuman experience (keyboard shortcuts, split inbox, snippets) alongside voice-matched drafting, the two can coexist.
What does ForthWrite offer that Superhuman's AI does not?
ForthWrite captures every draft vs. what you actually sent, uses the difference as a training signal, and shows the improvement curve on a dashboard - voice capture runs on all tiers, coaching analytics and the improvement dashboard are Standard+, and RAG-based draft-time injection is Pro. It also ships 9-provider BYOK on Standard and Pro, letting you route different emails to different AI models. Superhuman does not publish a comparable feedback loop or model-choice feature. Some competing AI features prioritize urgent messages or support batch drafting, but ForthWrite's edge is voice fidelity and measurable improvement.
Is ForthWrite a free Superhuman alternative?
ForthWrite's free tier includes 10 drafts per week with voice matching - no credit card required and no time limit. It is a free alternative for AI-assisted drafting, but not a full Superhuman alternative if you need a premium email client's workflow features. Superhuman costs $30/month with no free plan. If you are looking for a completely free way to get AI-assisted email drafting in Gmail or Outlook without switching email clients, ForthWrite's free plan is a starting point. It does not replicate Superhuman's keyboard shortcuts, read receipts, follow-up reminders, or mobile apps - those are email client features, not drafting features. Other free alternatives like Inbox Zero can help users reach inbox zero across their entire inbox without forcing a client switch.
Does ForthWrite work on mobile?
No. ForthWrite is a Chrome extension and works on desktop only - inside Gmail or Outlook Web in a browser. Superhuman has highly rated iOS and Android apps, and Superhuman's mobile experience is a real advantage if you need to stay responsive away from your desk. The biggest speed gains from Superhuman come from the desktop app, but if mobile email is a significant part of your workflow, Superhuman has a clear advantage here.
Can ForthWrite handle multiple email accounts?
ForthWrite works with Gmail and Outlook Web accounts. Each account is set up separately because ForthWrite is a drafting layer, not a unified inbox, and the voice profile is built from each account's sent history. Users who need unlimited email accounts, separate inboxes, or unified inbox workarounds across Gmail, Microsoft Outlook, and another IMAP provider will need a dedicated email app. Superhuman is stronger for keeping multiple email accounts in one place. Some alternatives also run as a web app inside Google Workspace, support Gmail through the Gmail API, and may be a better fit for teams that need end-to-end encryption, data protection, or collaboration features.
What is the best Superhuman alternative for team collaboration?
Missive is the strongest Superhuman alternative for team collaboration. It supports shared inboxes for team collaboration, allowing multiple users to manage emails together. It also allows internal chat within email threads and assignment of emails to specific team members. This is especially useful for support and sales teams that need to coordinate responses, delegate tasks, and keep internal discussions organized within the context of each email conversation. Superhuman lacks true shared inbox functionality and is designed for individual inbox management only.
What is the cheapest Superhuman alternative?
Mailman is the cheapest paid Superhuman alternative at $8/month (with a 21-day free trial), focusing on email batching and distraction reduction. Missive offers a free plan for individuals. Shortwave is also free to start with paid plans from $24/month. Mailbird offers a one-time $39.99 lifetime license - significantly cheaper than Superhuman's ongoing $30/month subscription. ForthWrite's free tier includes voice-matched AI drafting at no cost. The right choice depends on what you need: if you want a client-level Superhuman experience, Shortwave or Mailbird are the closest lower-cost options. If you primarily want AI drafting quality, ForthWrite's free plan is the starting point.
See the improvement curve for yourself
Free tier includes voice matching. No credit card, no API key. Compare your first ForthWrite draft to your first Superhuman draft and decide for yourself.