Comma Checker for Mac: Fix Punctuation Errors Instantly with WunderType

Why You Need a Comma Checker

Commas are the most misused punctuation mark in English. A misplaced comma changes meaning, a missing comma creates confusion, and a comma splice can undermine otherwise polished writing. If you have ever searched for a comma checker to catch these mistakes, you know that most tools either live inside a browser or require pasting text into a web app.

WunderType takes a different approach. It sits in your macOS menu bar and works as an AI-powered comma checker inside any application — your email client, text editor, Slack, Notion, or whatever you use to write.

How the Comma Checker Custom Prompt Works

WunderType's strength is Custom Prompts: user-defined AI text actions, each with its own instruction set and keyboard shortcut. To build a dedicated comma and punctuation checker, you create a Custom Prompt called "Comma Checker" and give it an instruction like:

Review the text for comma and punctuation errors. Fix comma splices, add missing commas after introductory phrases, correct Oxford comma usage, and fix any other punctuation issues. Preserve the original meaning and tone.

Assign it a shortcut — say ⌥⇧⌘C — and you are ready to go.

Before and After: Comma Errors Fixed

Here is a realistic example. Suppose you have typed the following in an email:

Before:

After reviewing the report I noticed several issues, the data was incomplete and the formatting was inconsistent. We need to fix the tables charts and graphs before the presentation on Monday.

There are multiple comma and punctuation problems here: a missing comma after the introductory phrase "After reviewing the report," a comma splice joining two independent clauses, and a missing Oxford comma in the list "tables, charts, and graphs."

Select the text, press ⌥⇧⌘C, and WunderType returns:

After:

After reviewing the report, I noticed several issues. The data was incomplete, and the formatting was inconsistent. We need to fix the tables, charts, and graphs before the presentation on Monday.

Every comma error is corrected. The comma splice is replaced with a full stop. The introductory phrase gets its comma. The Oxford comma appears where it belongs.

Common Comma Mistakes WunderType Catches

A well-crafted Comma Checker prompt handles the errors that trip up even experienced writers:

• Comma splices — Two independent clauses joined by a comma instead of a period, semicolon, or conjunction. Example: "The meeting ran late, everyone was tired."
• Missing commas after introductory phrases — "Before we begin" should be followed by a comma. Many writers skip it.
• Oxford comma inconsistency — Whether you prefer "red, white, and blue" or "red, white and blue," your Comma Checker prompt enforces your chosen style consistently.
• Comma before conjunctions — Knowing when "and" or "but" needs a preceding comma in compound sentences.
• Punctuation around quotation marks — Periods and commas inside or outside quotes, depending on your style guide.

Why Not Use a Free Comma Checker Online?

Free online comma checkers and punctuation tools work, but they come with trade-offs. You have to copy text out of your writing app, paste it into a browser tab, review the suggestions, then copy the corrected text back. That breaks your flow.

More importantly, every word you paste into a free online tool is sent to a remote server. If you are writing client emails, legal documents, or anything confidential, that is a privacy risk.

WunderType solves both problems:

• Works in place — Select text, press a shortcut, get corrected text. No copy-pasting, no tab switching.
• Privacy options — Run local AI models through Ollama so your text never leaves your Mac, or use your own API keys with cloud providers.
• No subscription — One-time purchase. No monthly fees for checking your commas.

Set Up Your Own Comma Checker in 30 Seconds

1. Open WunderType from your menu bar and go to Custom Prompts.
2. Click the + button to add a new prompt.
3. Name it "Comma Checker" and write your punctuation-checking instruction.
4. Assign a keyboard shortcut like ⌥⇧⌘C.
5. Start writing. Select any text and press your shortcut to check commas and punctuation instantly.

You can create as many Custom Prompts as you need — a comma checker, a full grammar and punctuation checker, a style enforcer, or anything else your writing demands.

Ready to stop worrying about commas? Download WunderType from the Mac App Store and build your perfect comma checker today.