Check JavaScript code for syntax errors using the Function constructor. Validate code before execution. Everything runs locally in your browser — nothing is uploaded.
Validate YAML syntax, check for indentation errors, and preview the parsed structure.
Find the ISO week number for any date. Also shows the day of the week and the current week of the year.
Check when daylight saving time starts and ends in the US for any year. Shows the exact dates and DST period length.
Check the status of hundreds of URLs at once — find broken links, redirects, and dead pages across your entire website. Essential for SEO audits before Google crawls your site.
Validates the structure, length, and check digits of IBANs from 70+ countries using the official ISO 13616 modulus-97 algorithm.
JavaScript Syntax Checker lets you check JavaScript code for syntax errors using the Function constructor. Validate code before execution. Everything runs locally in your browser — nothing is uploaded.. It works on any device with a modern web browser.
Check JavaScript code for syntax errors using the Function constructor. Validate code before execution. Everything runs locally in your browser — nothing is uploaded. It runs entirely in your browser — no software installation or data uploads required.
Direct text entry, file upload, or URL-based input — depending on the tool. Paste or type your content directly into the provided editor area.
Yes. After the initial page load, JavaScript Syntax Checker runs entirely on your device with no internet connection needed. All processing is done locally.
Tools cover JavaScript, CSS, HTML, SQL, Python, JSON, XML, CSV, and more. Check individual tool descriptions for specifics.
No. All code processing — formatting, minification, conversion, hashing — runs locally in your browser.
Yes. Since processing is local, performance depends on your device. Most operations handle large files without issue.
Yes. SQL uses sql-formatter, JSON uses native JSON.parse, and other formatters follow widely adopted formatting rules.
Yes. All developer tools work fully offline after the initial page load.
Time Converter
Convert between time units including seconds, minutes, hours, days, weeks, months, and years with precise decimal results.
Random Port Generator
Generate random TCP/UDP port numbers from well-known, registered, or dynamic ranges. Useful for network testing, Docker port mapping, and firewall configuration.
Chmod Calculator
Convert between numeric (755) and symbolic (u=rwx,g=rx,o=rx) chmod permission formats. See detailed breakdown for owner, group, and others.
Docker Run to Compose Converter
Convert docker run commands to docker-compose.yml format. Supports ports, volumes, environment variables, networks, restart policies, and container names.
Email Normalizer
Normalize email addresses by removing dots (Gmail), stripping +tags, and lowercasing. Process multiple emails at once for deduplication and cleaning.
Diff Checker
Compares two input texts side-by-side, highlighting inserted, deleted, and changed lines with distinct background colors.