Most development work involves small, repeated annoyances rather than hard problems: a JSON blob that will not parse, a regex that behaves differently in production, a timestamp in the wrong unit, an identifier that needs generating. Each is trivial, and each can waste twenty minutes without the right tool.
There is an argument for command-line or IDE solutions to all of these, and for work you do constantly, that is right. But there is a real case for browser tools too:
| Tool | Solves | Why it saves time |
|---|---|---|
| JSONLint | Invalid JSON | Reports the exact line of the syntax error instead of a vague parser message |
| Regex101 | Regex not matching | Live highlighting plus a token-by-token explanation |
| EpochConverter | Unreadable timestamps | Handles the seconds/milliseconds ambiguity explicitly |
| Base64 Encode | Embedding or inspecting data | Both directions, text and files, produces data URIs |
| UUID Generator | Needing unique IDs | Bulk RFC 4122 v4 generation |
| JSON Formatter | Minified walls of text | Pretty-prints an unreadable API response |
| HTML/CSS Beautifier | Mangled markup | Restores readable indentation |
| ColorHexa | Colour conversion | Hex, RGB, HSL and harmonies in one place |
A parser telling you "unexpected token" is nearly useless. JSONLint reports the line and position, and describes what it expected — which turns a hunt into a fix.
It reliably catches the mistakes that actually occur: trailing commas after the last array element, single quotes instead of double, unescaped characters inside strings, comments (which JSON forbids) and mismatched brackets. Once valid, it pretty-prints or minifies in the same place.
Regex fails silently: it matches the wrong thing, or nothing, and the reason is not obvious. Regex101 highlights matches live and — the genuinely valuable part — explains each token in plain language, so you learn why the pattern behaves as it does.
The debugger is also worth opening when a pattern is slow, because it makes catastrophic backtracking visible.
EpochConverter translates between Unix timestamps and readable dates in both directions, and its explicit seconds/milliseconds toggle resolves the most common timestamp bug. The rule: a 10-digit value is seconds, 13 digits is milliseconds. Getting it wrong produces 1970 dates or dates decades in the future.
Use it for transport, never for secrecy — it decodes instantly. It is genuinely useful for data URIs, but remember the roughly 33% size overhead, so keep embedded images to small icons.
Generate version 4 unless you have a specific reason not to. Version 1 embeds a timestamp and MAC address, which can leak more than you intend in a public API. Random UUIDs fragment database indexes more than sequential keys, so weigh that for very large tables.
The tools pay off most when used in a consistent order rather than reached for at random:
For non-sensitive data, yes. Never paste production credentials, private keys or real customer data into any online tool — generate sample data instead.
JSONLint is the standard choice because it reports the exact line and position of the error rather than a generic parse failure.
Almost always an engine mismatch. Select the flavour matching your language in Regex101 before testing.
A 10-digit timestamp is usually seconds; 13 digits usually means milliseconds. This single check resolves most timestamp confusion.
v4 (random) for nearly everything. v1 embeds a timestamp and MAC address, which can leak information.
No. All of them run in a browser tab, which is why they work on locked-down or borrowed machines.