Developer & Data Tools

CSV ⇄ JSON Converter

Convert CSV (with a header row) to JSON, or a JSON array of objects back to CSV.

Base64 Encode / Decode

Now part of a converter that handles hex, binary, Base64url, Base32 and percent-encoding too, with Unicode carried properly through UTF-8 and malformed input refused with a reason rather than silently mangled.

Open the encoding converter →

Everything still runs in your browser; the tool simply lives somewhere it can be found and linked to on its own. See all the cryptography tools.

URL Encode / Decode

Now part of the same converter, alongside hex, binary, Base64, Base64url and Base32.

Open the encoding converter →

Everything still runs in your browser; the tool simply lives somewhere it can be found and linked to on its own. See all the cryptography tools.

Hash Generator

Moved to the hash calculator, which now takes text as well as files — and shows the UTF-8 byte count beside the character count, since that difference is where most surprises come from.

Open the hash calculator →

Everything still runs in your browser; the tool simply lives somewhere it can be found and linked to on its own. See all the cryptography tools.

UUID Generator

Now has its own page, which marks the version and variant digits — a version 4 UUID carries 122 random bits, not 128, and that difference matters whenever somebody treats one as a secret.

Open the UUID generator →

Everything still runs in your browser; the tool simply lives somewhere it can be found and linked to on its own. See all the cryptography tools.

ZIP & unzip

Bundle files into a ZIP, or open one and pull files back out — on your device, with no upload.

1. Input
2. Configure
3. Export

When opening an archive, entries with suspicious paths (../ or absolute paths) are refused rather than extracted, and very large or very numerous entries are capped — a defence against maliciously crafted "zip bombs". Nothing extracted is ever executed; files are only offered to you as downloads.

CSV ⇄ Excel

Convert a spreadsheet between CSV and Excel without uploading customer data to a conversion site.

1. Input
2. Configure
3. Export

Going to CSV keeps only the values of one worksheet — formulas, formatting, charts and any other sheets are not part of the CSV format and will be left behind. "Keep values as text" stops IDs, phone numbers and postcodes losing their leading zeros, and stops long numbers turning into scientific notation.

Spreadsheet cleaner

Tidy up messy tabular data — stray whitespace, inconsistent headers, blank rows, duplicates — and see exactly what changed before you export.

1. Input
2. Configure
3. Export

Need to go further? Spreadsheet Cleanup & Reconciliation adds an editable list of steps you can reorder and switch off, explicit date and number conversion, and a full comparison of two exports — what was added, removed and changed, with every row accounted for. It runs on an address with no advertising or analytics on it at all.

Nothing is changed silently: every option is off unless you tick it, and the preview shows the counts before you export. Values are never coerced — a code like 007 stays 007, and an ambiguous date is left exactly as written rather than being guessed at.