DevLens: Free Online Developer Tools — 7 in One
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DevLens by ExcelGuru — The Developer Toolkit You Will Keep Open All Day
DevLens combines seven essential developer tools into one fast, browser-based interface — built for debugging, conversion, validation, and daily workflow efficiency without switching tabs.
Every developer has a set of tiny conversion tasks that consume far more time than they should. Converting a hex colour to RGB. Checking a Unix timestamp. Testing a regex. Formatting a broken JSON payload. These micro-tasks often send developers to multiple websites, break concentration, and slow down debugging sessions.
DevLens by ExcelGuru was built to solve that problem in one place. It is a free, browser-based developer toolkit that combines seven essential utilities into a single, fast, mobile-ready interface with zero sign-up, zero ads, and zero server-side processing.
What Is DevLens and Who Is It Built For?
DevLens is a single-page web application that bundles seven developer-focused conversion and testing tools behind a tabbed interface. Each tool is self-contained, so you can jump between JSON formatting, regex testing, colour conversion, timestamp decoding, and byte calculations without losing context or data.
Web Developers
Quick colour format lookups, regex pattern testing, and frontend debugging.
Backend Engineers
Unix timestamps, JSON payloads, configuration files, and structured data checks.
DevOps & Sysadmins
Storage conversions, bandwidth estimates, permissions, and binary interpretation.
Security & Data Teams
Encoding, decoding, payload inspection, and safe in-browser handling of sensitive values.
Complete Guide to All 7 DevLens Tools
Each tool is built for a specific developer workflow, but all of them share the same zero-friction experience.
| Tool | Scope | Covers |
|---|---|---|
| 🔢 Number Base | 4+ bases | Decimal ↔ Binary ↔ Hex ↔ Octal ↔ Base-32/36, 32-bit visual |
| 💾 Bits & Bytes | 12 units | bit, nibble, byte, KB/MB/GB/TB/PB, KiB/MiB/GiB/TiB + bandwidth calc |
| ⏰ Unix Timestamp | 6+ formats | Epoch ↔ ISO 8601 ↔ RFC 2822 ↔ UTC, time-ago, week/day of year |
| 🎨 Color Formats | 6 formats | HEX ↔ RGB ↔ RGBA ↔ HSL ↔ CMYK + named colours + WCAG luminance |
| 🔤 ASCII / Unicode | 5 encodings | Char ↔ dec/hex, Unicode points, HTML entities, URL, Base64 |
| 🔍 Regex Tester | Live tool | Match highlighting, group capture, presets, JavaScript flags |
| 📋 JSON Formatter | 5 tools | Format, minify, validate, JSON→CSV, syntax colour, Excel export |
What Each Tool Does
Number Base Converter
Converts integers between Decimal, Binary, Hexadecimal, Octal, Base 32, and Base 36 instantly. Includes a 32-bit binary visualiser with bit-by-bit highlighting for low-level debugging.
755 octal = 111 101 101 binary
Bits & Bytes Converter
Converts between decimal and binary storage units and includes a transfer-time calculator for bandwidth estimates. Useful for backups, uploads, cloud storage, and capacity planning.
1 TB ≈ 931 GiB
Unix Timestamp Converter
Converts Unix timestamps in seconds or milliseconds into human-readable formats including ISO 8601, RFC 2822, UTC, relative time, week number, and day number of the year.
Date.now() returns milliseconds
Color Format Converter
Parses HEX, RGB, RGBA, HSL, HSLA, CMYK, and named colours. Outputs full conversions, colour channels, luminance, and contrast ratios.
#22C55E → rgb(34, 197, 94)
ASCII / Unicode Encoder
Breaks text into per-character code point data and supports Base64, URL encoding, and HTML entity encoding/decoding for full text transformation workflows.
🌍 = U+1F30D
Regex Tester
Provides live match highlighting, captured groups, named group support, and useful presets for common patterns like emails, URLs, UUIDs, hashtags, and colours.
(?<name>pattern)
JSON Formatter & Validator
Validates JSON in real time, pinpoints syntax errors, applies syntax colouring, formats or minifies data, converts flat arrays to CSV, and exports structured Excel output when appropriate.
{ "status": "valid", "tool": "DevLens" }
Cross-Tool Features That Make DevLens Better
Click to Copy
Every important output can be copied instantly without manual selection.
Excel Export
Each tool can produce structured spreadsheet exports for records, audit trails, or documentation.
Live Updating
All tools respond to each keystroke, removing the need for submit buttons and reducing friction.
Specific Error Feedback
Validation failures explain exactly what is wrong instead of showing generic error states.
Why DevLens Instead of Separate Tools?
A typical debugging session can involve checking a timestamp in one tab, a colour value in another, formatting JSON in a third, and testing a regex in a fourth. Every switch costs focus.
DevLens consolidates those workflows into one browser tab with no advertising, no accounts, and no data leaving the browser. That privacy-first architecture matters when working with real logs, real payloads, and real production values.
Conclusion: The Developer Toolkit You Will Keep Open All Day
DevLens by ExcelGuru brings together number conversion, storage calculations, timestamp parsing, colour conversion, encoding tools, regex testing, and JSON formatting into one fast, free, and offline-capable utility.
It is designed for the way developers actually work: switching rapidly between tasks, needing precise answers immediately, and often working with data that must remain private.
Frequently Asked Questions
Clear answers about privacy, offline use, JSON limits, timestamp detection, and developer-focused functionality.
No. Every operation in DevLens — including number conversion, JSON parsing, regex matching, and timestamp calculation — runs entirely in your browser using JavaScript.
No data is sent to any server, and nothing is logged or stored. You can safely use DevLens with real API keys, production JSON payloads, and sensitive configuration values.
Yes. Once the page has loaded, including Google Fonts and JetBrains Mono, DevLens operates fully offline.
All logic is self-contained in the HTML file. You can also save the file to your device and open it directly for permanent offline use without any internet connection.
A Kilobyte (KB) is 1,000 bytes using the decimal SI standard commonly used by storage manufacturers and network providers.
A Kibibyte (KiB) is 1,024 bytes using the binary IEC standard often used by operating systems and programming tools.
The same distinction applies to MB vs MiB, GB vs GiB, and TB vs TiB. That is why a 1 TB drive appears as roughly 931 GiB in Windows — both values are correct under different unit definitions.
Yes. DevLens uses the browser’s native JavaScript RegExp engine, which fully supports named capture groups using the (?<name>pattern) syntax.
Named groups are displayed in the match details panel alongside their captured values.
DevLens handles JSON files of moderate size well — typically up to a few hundred kilobytes.
Very large JSON files spanning multiple megabytes may slow the browser during live validation and syntax colouring, because all processing happens in the main thread.
For extremely large JSON files, a dedicated desktop editor is usually a better option.
DevLens uses a simple heuristic: if the input has 13 or more digits, it is treated as milliseconds, which matches JavaScript’s Date.now() format.
If it has fewer than 13 digits, it is treated as seconds, which is the standard Unix epoch format.
This handles the vast majority of real-world timestamps correctly without requiring manual selection.