Developer Tools Calculators
Developer utilities for formatting data, inspecting URLs, generating identifiers, and estimating website transfer emissions. Most text tools run in your browser; website carbon checks request public pages through DevCalc's server.
11 calculators available in this domain
Logical Groupings in Developer Tools
Website Performance & Sustainability
Measure public page weight, discovered requests, estimated CO2e and recognised green hosting.
Data Formatting & Decoding
Pretty-print JSON payloads, decode JWT tokens, find text differences, and translate Base64/URL streams.
Cryptographic Hashing & Randomization
Generate UUID v4 identifiers, SHA-256 checksums, and POSIX epoch timestamp conversions.
How to Choose the Right Calculator
Identify your specific scenario to select the appropriate mathematical or statutory model:
Inspecting claims and expiration on an OAuth2 / JWT bearer token
Decodes Header and Payload claims locally without sending tokens over external networks.
Use JWT DecoderGenerating collision-resistant primary keys for distributed microservices
Generates RFC 4122 v4 identifiers with 122 bits of cryptographic entropy.
Use UUID GeneratorAll Developer Tools Calculators
Click any tool to open the interactive calculatorJSON Formatter
Fix, format, beautify, validate, and minify JSON data instantly with one click. Free online JSON Formatter and JSON Beautifier for developers.
Website Carbon Footprint Calculator
Estimate a web page's transfer weight, HTTP requests and CO₂e per visit, check whether its hosting is recognised as green, and project monthly or annual emissions.
Android UI Inspector
Connect an Android phone through USB, capture its current screen and UI hierarchy, and copy Appium, UIAutomator2, XPath, or ADB tap selectors.
UUID Generator
Generate UUID v4 identifiers instantly. Create single or multiple unique UUIDs for development, databases, APIs, testing, and distributed architecture.
Base64 Encoder Decoder
Encode text or binary data to Base64 strings and decode Base64 back to its original format instantly. Free, secure, client-side online developer utility.
URL Encoder Decoder
Encode and decode URLs instantly. Convert special characters into percent-encoded, URL-safe formats or parse encoded strings back into human-readable text.
JWT Decoder
Decode JWT tokens instantly, right in your browser — nothing is sent to a server. View the header, payload, expiration time, and issue time at a glance.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes directly in your browser for checksum comparison, development, testing, and data-integrity workflows.
Unix Timestamp Converter
Instantly convert Unix timestamps into readable dates, or dates into Unix timestamps. Supports Epoch time, UTC, milliseconds, and other developer-friendly timestamp calculations.
Regex Tester
Test regular expressions instantly against text input. Validate patterns, find matches, and debug regex expressions online.
Diff Checker
Compare two versions of text, code, JSON, or configuration side by side or inline. Highlight added and removed lines locally, with options to ignore case or whitespace.
Frequently Asked Questions about Developer Tools Tools
Are API keys or sensitive JSON payloads stored on your server?
JSON, URL and other text utilities run in your browser. The website carbon calculator sends the public website URL to DevCalc's server to measure the page and caches the result by domain for 24 hours. Do not enter private URLs or secrets.