Can I vibecode Grammarly?

KINDA · weekend project

price $30/moyou'd save $360/yrbuild time multi-daycategory ✍️ ai writingreplaced by 1 people

You can build grammar checks and rewrites, but Grammarly's moat is cross-app extensions, inline UX, enterprise controls, writing telemetry, and long-running language quality.

the prompt

Build me a personal writing checker to replace Grammarly. Requirements:

- Grammar engine: LanguageTool running locally via its official Docker image;
  grammar checks never leave my machine.
- A local web page (Node + Express, binds to localhost): paste text, see
  LanguageTool issues underlined with hover explanations, click a suggestion
  to apply it.
- An LLM rewrite pane (key in .env) with three buttons: tighten, friendlier,
  formal. Show a diff against my original before I accept anything.
- A personal dictionary file (dictionary.txt) of names and jargon to never
  flag, passed to LanguageTool on every check.
- CLI mode: `check <file.md>` prints issues with line numbers, exits nonzero
  if any, so it can run as a git pre-commit hook on docs.
- Everything local except the optional LLM call; no accounts, no telemetry.
- Out of scope: a browser extension and inline suggestions inside Gmail,
  Docs, or Slack. This is a destination I paste into, that is the honest
  trade against Grammarly.
- README: Docker setup for LanguageTool, the roughly 1 GB of RAM it wants,
  and where the LLM key goes.

$ open in your agent (prompt prefilled, you press enter) or copy it raw · this prompt is generated from the build plan · improve it via PR

why people still pay

They pay because suggestions appear inside the apps where writing actually happens.

what you lose

xinline suggestions everywhere

xdocument/email integrations

xtone/brand controls

xenterprise admin

xpolished false-positive handling

share on X ↗"I just replaced Grammarly ($30/mo) with one prompt"

the escape hatch

Don't feel like building it? These folks already made it free.

HarperA fast English grammar checker that stays on your device and mostly keeps its opinions to itself.14kaug 2026open source↗

Writing ToolsSelect text anywhere, hit a hotkey, and fix, rewrite, summarize, or obey a custom instruction without opening another tab.2.4kmay 2026open source↗

WritingToolA LibreOffice extension with long-document checks, style statistics, profiles, and local AI; installing Java is the cover charge.65jul 2026open source↗

all 4 free alternatives to Grammarly →· no votes, no pay-to-list · just what's real

the numbers

Grammarly pricing

plan	monthly	annual (per mo)	what you get
free	$0/user	$0/user	100 generative-AI prompts/month.
pro	$30/user	$12/user	2,000 AI prompts/member/month; up to 149 seats; 1 style guide; 1 brand tone; 2 groups.
enterprise	custom	—	Unlimited prompts, members, style guides, brand tones, and groups.

free tier100 generative-AI prompts/month

billingmonthly + quarterly + annual for Pro; Enterprise is custom

hidden costsAdditional Pro seats are prorated. A 7-day trial is available only for eligible accounts.