FreeTools Blog
In-depth guides on text cleanup, privacy redaction, developer workflows, converters, and generators — written to be actionable, not padded.
JSON Formatter vs Validator vs Minifier: When to Use Which
Format, validate, minify — three JSON verbs that sound similar and do completely different things. Here is when to reach for each, and the gotchas that waste hours when you do not.
Base64 Explained Simply: Encoding, Decoding, and When to Use It
What Base64 actually is, how 3 bytes become 4 characters, why it makes files 33% bigger, and the real places you encounter it — data URLs, JWTs, PEM keys, HTTP Basic auth.
UUID vs Random String vs Hash: Which to Use for IDs
Not all IDs are the same. A decision framework for UUIDs, random strings, and hashes — with collision math, the v4 vs v7 trade-off, and the anti-patterns that cost hours.
How to Redact Sensitive Data Before Sharing: a PII Safety Guide
The workflow to strip names, emails, phones, IPs, and card numbers from any document before you share it — and the failure modes that leak data even after you think you redacted.
Password Strength Explained: Build Passwords Hackers Cannot Crack
Why most password advice is 20 years out of date. Entropy, length, passphrases, and the practical recipe that actually stops real-world attacks.
Remove Duplicate Lines from Any List in One Click (Emails, URLs, Data)
Deduplication sounds trivial until the list comes from copy-paste. Here is the 10-second workflow that handles case, whitespace, and invisible Unicode — plus the gotchas that break the naive approach.
Word Counter for Writers: SEO, Social, and Essay Limits Cheatsheet
SEO meta descriptions, tweets, essays, SMS — every length limit you actually have to hit, with the rules behind each number and the workflow to land on target.
CSV to JSON (and Back): 3 Ways to Convert Without Writing Code
CSV in, JSON out. Three ways to do it without installing anything, plus the quoting, BOM, and typing gotchas that break naive parsers in the wild.
Markdown to HTML: Convert Without Losing Formatting
Markdown looks like one language but is actually five overlapping ones. Here is the converter workflow that survives the round-trip into Substack, Notion, Gmail, or your CMS.