10 Developer Tools Every Engineer Should Bookmark
The right utility at the right moment saves the minutes that add up to hours. These ten browser-based tools cover the gaps that no IDE plugin quite fills.
JSON Formatter
Paste raw JSON from an API response and instantly see it beautifully indented. The validator highlights the exact line causing a syntax error — saving the minutes you would otherwise spend manually counting brackets. The minifier lets you reverse the process when you need a compact payload.
JWT Decoder
JSON Web Tokens look opaque but are just Base64-encoded JSON with a signature. The JWT Decoder splits the token into header, payload, and signature, then formats each part. You can see the expiry timestamp (exp), issuer (iss), and any custom claims at a glance — without touching openssl or writing a one-off script.
Base64 Encoder / Decoder
Base64 encoding is everywhere: email attachments, data URLs, HTTP Basic Auth headers, binary data embedded in JSON. Decode an Authorization header to verify credentials. Encode a small image to embed it inline in HTML. Far faster than pulling up a Python shell.
Hash Generator
Verify a downloaded file's integrity by comparing its SHA-256 hash to the one published on the project's release page. Check that two strings produce the same MD5 (useful for debugging legacy systems). The hash generator supports MD5, SHA-1, SHA-256, and SHA-512.
Password Generator
Generating a strong, unique password for a new service account or database user does not require a password manager open. Set length, include uppercase, lowercase, numbers, and symbols, then copy. All generation happens in your browser using the Web Crypto API — nothing is logged.
UUID Generator
Need a UUID v4 for a test fixture, a migration script, or a new database record? Generate one (or a batch) instantly. The tool uses crypto.randomUUID() when available, falling back to a cryptographically secure PRNG — so these are safe to use as actual identifiers, not just placeholders.
Regex Tester
Live regex testing with match highlighting and named group support. Write the pattern, paste in your test string, and see matches highlighted in real time. Useful when building input validation, data extraction pipelines, or log analysis scripts.
YAML ↔ JSON Converter
Copy a YAML config block from a README, paste it in, and get valid JSON back — ready to drop into a script or API call. Convert in the other direction when a tool expects YAML but you have JSON. Bidirectional and instant.
Cron Expression Builder
Cron syntax is terse by design. "0 */6 * * 1-5" is unambiguous to the scheduler but not to the human reading the CI config three months later. Paste any cron expression and get a plain-English description of when it runs: "Every 6 hours, Monday through Friday."
My IP Address
Your current public IP address, together with ISP, approximate location, and timezone. Useful for checking which IP is hitting an external service from a given machine, debugging allowlist rules, or verifying that a VPN is routing traffic correctly.
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