Compose AI vs Letty

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors.

The short answer

Cheaper paid plan: Letty — $9/mo vs $9.99/mo for Compose AI
Free plan: Both have one
Higher Trust score: Compose AI — 96 vs 69 for Letty
Best fit: Compose AI: Heavy email writers who churn out routine replies in Gmail · Letty: Gmail-heavy users who want drafted replies rather than typing every response
Status: Both up at our last check — Compose AI Oct 16, 2026, Letty Oct 15, 2026

From our own records as of each tool's last check. Anything we have not confirmed is left out rather than guessed. How we verify

Compose AIFree Chrome extension that autocompletes sentences and email replies as you type across the web

LettyGmail-only Chrome extension that drafts replies in your writing style and can be trained on your documents.

Side by side

Fact	Compose AI	Letty
Category	AI Writing Assistants	Email Writing
Pricing model	Freemium	Freemium
Starts at	$9.99/mo	$9/mo
Trust score	96 / 100	69 / 100
Platforms	Chrome extension	Chrome extension
Company	Compose AI, Inc.	—
Launched	2021	—
Last verified	Oct 16, 2026	Oct 15, 2026

What our research says

Compose AI

A low-friction way to speed up routine email and doc writing: the free tier installs in a minute and completes sentences anywhere in Chrome. The extension is still being updated, but its free caps are small and browser-native AI features now cover much of the same ground at no cost, so the paid tiers have to earn their place.

Pros

Basic extension is free with no time limit
Autocomplete works across most web text fields, not one app
Learns personal writing style for suggestions
Annual billing cuts the Premium price by a third

Cons

Chrome-only, with no public API or desktop apps found
Free plan caps AI writing at 1,500 words a month
Marketing site copy and copyright are still dated 2024, which makes the product look less maintained than its store listing suggests

Letty

Letty drafts Gmail replies that match your tone and can be grounded in documents or sites you feed it, which makes it useful if most of your email already lives in Gmail. It doesn't help outside Gmail yet, and the free tier's 10 credits a month will run out fast for anyone emailing daily.

Pros

Generates contextual reply suggestions instead of generic templates
Can be trained on specific documents or websites for grounded answers
Three clear pricing tiers from free up to unlimited credits

Cons

Only works inside Gmail in Chrome; Outlook and Zoho are listed as planned but not shipped
Free tier's 10 monthly credits cover only light use

Which one fits

Choose Compose AI if you need

Heavy email writers who churn out routine replies in Gmail
Non-native English speakers who want inline phrasing help
Anyone testing writing autocomplete without paying

Choose Letty if you need

Gmail-heavy users who want drafted replies rather than typing every response
People who repeatedly reference the same documents or product pages in email