Guides for everyday data problems
Eight short, answer-first guides to the data problems these tools exist for — each one links straight to the tool that does the job, locally in your browser.
- How to pretty-print JSON
Paste JSON into the formatter and press Format — 2-space indents, exact error positions — or use jq in the terminal. The file never leaves your tab.
- How to fix “Unexpected token” in JSON
Unexpected token means the parser hit illegal syntax: a trailing comma, single quotes, comments or an HTML error page. Find the exact line locally.
- JSON vs YAML vs CSV: which format for which job?
JSON for APIs and precision, YAML for human-edited configs, CSV for tabular exports — how data model, comments and types decide, with converters.
Tool: JSON ↔ YAML Converter
- How to decode a JWT (and why that isn't verifying it)
Split the token on its two dots and Base64URL-decode the first two segments — no key needed. Decoding shows the claims but never verifies anything.
Tool: JWT Decoder
- Base64 vs Base64URL: what's the difference?
Base64URL swaps + and / for - and _ and drops = padding so tokens survive URLs. That is why JWT segments fail standard decoders, and how to convert.
Tool: Base64 Encode / Decode
- UUID v4 vs v7: random or time-ordered?
v4 is 122 random bits; v7 leads with a 48-bit timestamp so IDs sort by creation time (RFC 9562). v7 suits database keys, v4 hides creation time.
Tool: UUID Generator
- SHA-256 vs SHA-1 vs MD5: which hash should you use?
Use SHA-256 for anything that matters — SHA-1 and MD5 are collision-broken and fit only legacy checksums. What broken means and when it bites you.
- Unix timestamps: seconds vs milliseconds
Count the digits: 10 means seconds, 13 means milliseconds. Mixing them lands in January 1970 or the year 56637 — two bug signatures explained.
Tool: Unix Timestamp Converter