Screaming Snake Case Converter

This screaming snake case converter changes any name into SCREAMING_SNAKE_CASE. Type a phrase, a camelCase variable or a kebab-case key. The tool makes an uppercase name with an underscore between each word. Paste a list with one name on each line to convert all of the names at the same time.

Type or paste names in the box. The tool shows the result immediately. Click Copy for one name or Copy all for a list.

Input:

userId
apiBaseUrl
max-retry-count
XMLHttpRequest
database url

Output:

USER_ID
API_BASE_URL
MAX_RETRY_COUNT
XML_HTTP_REQUEST
DATABASE_URL

Screaming snake case is a naming style for code. It has two rules:

• All letters are uppercase.
• An underscore (_) separates each word.

The name comes from snake_case. snake_case also uses underscores, but with lowercase letters. The uppercase letters look like "screaming" text. Other names for the same style are UPPER_SNAKE_CASE, CONSTANT_CASE and MACRO_CASE.

The Also as row under the result shows the first name in these other styles. Click a style to copy it.

Constants

Many style guides use SCREAMING_SNAKE_CASE for values that do not change. Examples are JavaScript and TypeScript, Python (PEP 8), Java, C and C++.

const MAX_RETRY_COUNT = 3;

Environment variables

Shells, Docker, CI systems and .env files use SCREAMING_SNAKE_CASE for environment variable names.

DATABASE_URL=postgres://localhost/app
STRIPE_SECRET_KEY=sk_test_123

Feature flags and config keys

Teams use the same style for feature flags and configuration keys, for example ENABLE_NEW_CHECKOUT.

Frameworks show only variables with a special prefix to the browser:

• Next.js: NEXT_PUBLIC_
• Vite: VITE_
• Create React App: REACT_APP_

Click a Prefix chip to add the prefix to each name. To use a different prefix, type it in More options. If a name already has the prefix, the tool does not add it again.

To make .env lines, set .env lines to on in More options. The tool keeps each value after the = sign.

Input (prefix VITE_, .env lines on):

apiUrl=https://api.example.com
debugMode=true

Output:

VITE_API_URL=https://api.example.com
VITE_DEBUG_MODE=true

Click Download .env to save the result as a file.

The converter starts a new word at:

• a space, a hyphen (-), a dot (.) or an underscore (_)
• an uppercase letter after a lowercase letter: userName becomes USER_NAME
• the last capital of an acronym: XMLHttpRequest becomes XML_HTTP_REQUEST

Other rules:

• Numbers stay with the word before them. base64Url becomes BASE64_URL.
• Accents are removed. café becomes CAFE.
• Apostrophes are removed. don't stop becomes DONT_STOP.
• Symbols are removed. The tool never makes two underscores together or an underscore at the start or the end.
• Correct names do not change. API_KEY stays API_KEY.

• The name starts with a number. Most languages and shells do not accept 2FA_CODE. Add a word or a prefix first, for example APP_2FA_CODE. The tool shows a warning for these names.
• The name has a space or a hyphen. API-KEY is not a valid constant or variable name in most languages. Use API_KEY.
• The browser prefix is missing. Next.js and Vite do not show a variable to browser code without NEXT_PUBLIC_ or VITE_.
• Secrets have a public prefix. A variable with NEXT_PUBLIC_ or VITE_ goes into the browser code. Do not put secret keys in these variables.

• Case converter: change text to lowercase, title case and other text cases.
• Slug generator: make lowercase URL slugs with hyphens.
• Text replacer: replace each underscore with a space to change SCREAMING_SNAKE_CASE back into words.
• HTML indent code: indent the HTML templates that use your constants.
• Convert small letter to capital letter: make all letters uppercase and keep the spaces.
• CSV to JSONL: change CSV config tables into JSON Lines.

Your names stay in your browser. The tool does not send them to a server.

Paste your names above and copy your SCREAMING_SNAKE_CASE constants now.