URL / Encode.
URL percent-encoding, HTML entity encoding, and dev-style case conversion — three panels, one page. Handles the daily encoding tasks that eat time when you have to look up the right function every single time. All in your browser.
A short note on each.
URL encoding: encodeURIComponent escapes everything that isn't a URL-safe character, including & / ? # = +. Use it for anything going into a query string value, a path segment, a cookie, or a fragment. encodeURI preserves those reserved characters — use it when you have a full URL and just need to escape spaces and unicode. Using the wrong one is how you end up with either double-encoded output or a URL where %26 should have been &. The "encode space as +" option is for application/x-www-form-urlencoded contexts, which actually require + for spaces rather than %20.
HTML entities: the 5 reserved entities (&, <, >, ", ') cover most text-content needs. Attribute contexts are stricter and benefit from numeric entities for any non-ASCII or suspicious character. The "All" mode encodes every printable character except A-Z a-z 0-9 - _ . ~, which is overkill for HTML but useful when piping through email, CSV, or anything that might interpret markup.
Case conversion: the tokenizer splits on casing changes (fooBar → foo, Bar), explicit separators (-, _, ., space), and consecutive caps (XMLHttpRequest → XML, Http, Request). Every result is rebuilt from those tokens. If you paste userEmail_address you'll see it become USER_EMAIL_ADDRESS, user-email-address, UserEmailAddress, etc. in every conversion card.