The Capitalizer

The Capitalizer is a title capitalization tool that turns text into proper title case according to style rules of the AP, APA, CMS, MLA, NYT, or WP. This post shares a little bit about the process of creating the app.

by Ryan Feigenbaum

The Capitalizer website

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The Capitalizer

The Capitalizer website

I recently launched my first web app, The Capitalizer. It's a tool for turning text into title case according to the style rules of the Associated Press (AP), American Psychological Association (APA), Chicago Manual of Style (CMS), Modern Language Association (MLA), New York Times (NYT), and Wikipedia (WP).

These style rules each dictate slightly different approaches to how titles should appear. For example, the Chicago Manual of Style and Modern Language Association instruct you to lowercase all prepositions, while the Associated Press, American Psychological Association, and New York Times instruct you to lowercase prepositions only if they're four letters or fewer, and Wikipedia to lowercase them if they're five letters. In a perfect world, they'd all be the same, but we're left with tedious differences between these rules that are liable to drive you insane.

I built The Capitalizer to ease that pain! It will capitalize your title automatically, with a high (but not yet perfect) rate of accuracy. The Capitalizer can also easily handle hundreds thousands of titles at once. I recently converted nearly 20,000 titles in under a second. This bulk capitalization could be useful if you're writing a bibliography with a lot of sources that are not in the proper format, constructing a conference program with hundreds of papers with titles in different styles, or standardizing a list of your favorite books.

The Capitalizer — A Lightning-Fast Title Capitalization Tool
A lightning-fast title capitalization tool to convert your text into proper title case according to AP, APA, CMS, MLA, NYT, or WP style rules.


The Capitalizer includes a few bonuses in the capitalization processes. First, all titles entered will be trimmed of extra whitespace. That means that if you're pasting in titles that are preceded or followed by extra spaces, those spaces will be removed from the converted title. Second, double hyphens (--) and en dashses (–) that separate a clause will be converted to em dashes (—).

The Future

The Capitalizer is currently in version 1.0. I am continually refining the internal logic to make the capitalization engine more accurate. Currently, I'm working on improving the hyphenation rules for each style and the correct conversion of adverbal and adjectival prepositions. Also, I am working on making the web site a progressive web app (PWA), which means that it will remain fully functional even without an internet connection, for those times when you just really need to capitalize your titles.

Tech Stack

I built The Capitalizer using Vue.js, a progressive Javascript library. The source code is available on my GitHub.—

Have questions about The Capitalizer or have a suggestion for improvements or new features? Contact me on Twitter.

👉 What are you waiting for? Go capitalize some titles.