Five small conversions developers hit constantly
None of these tools are complicated on their own, but they come up constantly during debugging — decoding a value, reformatting a payload, looking up what a file extension should serve as, or converting a timestamp you can't read at a glance.
Base64 — encoding, not encryption
Base64 encodes plain text into Base64 and decodes Base64 strings back into their original content.
When to use it: decoding a Base64 value found in an API response, JWT, or config file; encoding binary or text data for safe transport in formats that don't support raw binary like JSON or URLs; or quickly inspecting a Base64-encoded Basic Auth header.
Reading results: Base64 is encoding, not encryption — anyone can decode it instantly, so it provides zero security on its own. Seeing readable Base64 in a header or token is completely normal; never mistake its presence for an indicator that data is protected.
URL Encode / Decode — safe characters in a URL
URL Encode / Decode percent-encodes special characters in a string for safe inclusion in a URL, and decodes percent-encoded strings back to their original form.
When to use it: building a query string containing spaces, special characters, or non-ASCII text; decoding a confusing query parameter to see what it actually contains; or debugging a broken link caused by unencoded spaces, ampersands, or slashes in a parameter value.
Reading results: a space becomes %20 (or + in query strings specifically — an older convention), and reserved characters like &, =, and / get encoded when they appear inside a parameter value rather than as URL structure. Double-encoding is a common bug — check whether a string is already encoded before encoding it again.
JSON Formatter — validating and reading payloads
JSON Formatter validates JSON syntax and reformats it with proper indentation, pointing to the exact location of any syntax error.
When to use it: debugging an API response or request payload that's failing to parse, making minified JSON readable for review, or quickly checking whether a config file is valid before deploying it.
Reading results: the error location reported is usually where the parser gave up, which is often slightly after the actual mistake — a missing comma on the previous line, for example. If the reported location looks fine on inspection, check the line just before it first.
MIME Type — what a server should send
MIME Type looks up the standard MIME type associated with a file extension — what a server should send as the Content-Type header for that file.
When to use it: setting the correct Content-Type header when serving a file from custom code, debugging why a browser downloads a file instead of displaying it inline (or the reverse), or configuring a web server's MIME mapping for an uncommon extension.
Reading results: some extensions map to more than one valid type depending on context — .js as text/javascript versus the older application/javascript, for example. When there's a choice, prefer the current standard recommendation over legacy values still seen in older server configs.
Timestamp — epoch to human-readable
Timestamp converts Unix epoch timestamps (seconds since January 1, 1970) into human-readable dates, and vice versa, across time zones.
When to use it: reading raw epoch values in logs, API responses, or database fields; converting a human date into epoch format for an API call or script; or checking what time a token, certificate, or session actually expires in local time.
Reading results: watch for seconds versus milliseconds — a 13-digit number is almost always milliseconds, a 10-digit number is seconds, and mixing them up gives a date wildly in the wrong century. Always confirm which time zone a converted "human-readable" result is shown in before relying on it for anything time-sensitive.
How these fit together
Base64 and URL Encode/Decode both deal with making data safe to transport, just at different layers — one for binary-in-text, one for special-characters-in-URLs. JSON Formatter, MIME Type, and Timestamp are closer to everyday debugging aids: reformatting a payload, checking a header value, or making sense of a number that's actually a date.