Developer Utilities - Free Online Tools
Miscellaneous development utilities that don't fit neatly into other categories. Test regex patterns, build cron expressions, decode user agents, validate HTML, and more. These are the tools that solve specific problems developers encounter regularly.
Browser-based tools that work offline. Nothing gets uploaded. Everything runs locally.
Available Tools
HTML/JS Playground
Write HTML, CSS, and JavaScript and see the results instantly in a live preview. Perfect for testing snippets, prototyping ideas, or learning web development.
Cron Expression Builder
Build or parse cron expressions with a visual builder. Get human-readable descriptions, quick presets, and see the next 5 run times.
HTTP Header Viewer
View HTTP response headers for any URL. Supports GET and HEAD methods with redirect following options.
User-Agent Parser
Parse and analyze user agent strings. Extract browser, OS, device, and engine information with bot detection.
Domain to IP Lookup
Resolve domain names to IP addresses. Shows both IPv4 (A records) and IPv6 (AAAA records) with copy functionality.
IP to Domain Lookup
Reverse DNS lookup to find domains associated with an IP address. Shows PTR records (hostnames) for the given IP.
Why Use Developer Utilities?
Development involves countless small tasks that don't require full applications. Testing a regex before adding it to code. Building a cron expression for a scheduled job. Parsing a user agent to understand what browser caused an error.
These utilities solve specific problems quickly. They're too simple to justify installing software, but too annoying to do manually. Having them accessible in a browser means you can solve the problem and move on.
Many of these tools also help with debugging. Can't figure out why CORS is failing? Check the headers. Need to know what a cryptic user agent string means? Parse it. These tools give you visibility into things that are normally opaque.
Common Use Cases
- • Testing regex patterns before implementing them in production code
- • Building cron expressions for scheduled jobs and tasks
- • Debugging CORS issues by examining HTTP headers
- • Identifying browsers and devices from user agent strings
- • Looking up IP addresses when debugging networking issues
- • Validating HTML email rendering across different email clients
- • Prototyping HTML/CSS/JavaScript quickly without setting up a project
- • Generating meta tags for SEO and social media optimization
- • Checking DNS resolution for domain configuration
- • Understanding server responses by viewing HTTP headers
Related Categories: Text Tools | Security | Formatters