DevCvt guides https://devcvt.com/blog Free online developer tools for JSON, Base64, JWT, timestamps, cron, regex and diffs. Everything runs inside your browser — nothing you paste is uploaded to a server. en How to check whether a browser tool really keeps your data local https://devcvt.com/blog/how-to-verify-a-browser-tool-keeps-your-data-local https://devcvt.com/blog/how-to-verify-a-browser-tool-keeps-your-data-local A repeatable way to test any web tool's claim that your input stays on your device — using the network panel, offline mode, and the page source. Tue, 22 Sep 2026 00:00:00 GMT 64-bit IDs break the moment they pass through JSON.parse https://devcvt.com/blog/64-bit-ids-in-javascript https://devcvt.com/blog/64-bit-ids-in-javascript Why snowflake IDs and database primary keys silently change value in JavaScript, how to spot it, and the two fixes that actually work. Sun, 20 Sep 2026 00:00:00 GMT Five cron expressions that behave differently than people expect https://devcvt.com/blog/cron-expressions-that-surprise-people https://devcvt.com/blog/cron-expressions-that-surprise-people The day-of-month and day-of-week trap, DST gaps, step values outside their range, and other reasons a schedule fires when nobody expected it to. Fri, 18 Sep 2026 00:00:00 GMT What to do in the first hour after pasting a secret into a website https://devcvt.com/blog/what-to-do-after-pasting-a-secret https://devcvt.com/blog/what-to-do-after-pasting-a-secret A calm, ordered response for the moment you realise you pasted a production key into an online tool — rotate first, investigate second. Tue, 15 Sep 2026 00:00:00 GMT