Free Online Developer Tools — JSON, Base64, Hash & More
Format, validate, encode, and transform data. All tools are free, no signup required.
JSON Formatter
Format, validate, and prettify JSON data online for API debugging and code review
Base64 Encoder
Encode and decode Base64 strings and files for APIs, emails, and data URIs
URL Encoder
Encode and decode URL components online for safe query strings and API parameters
Hash Generator
Generate MD5, SHA-256, SHA-512, BLAKE3, and 25+ cryptographic hashes to verify file integrity
Regex Tester
Test and debug regular expressions online with live matching and capture groups
Color Converter
Convert colors online between HEX, RGB, HSL, OKLCH, and CMYK for CSS and design
Epoch Converter
Convert Unix timestamps to human-readable dates online with live clock and timezone support
HMAC Generator
Generate HMAC-SHA256 and HMAC-SHA512 authentication codes to sign API requests and verify webhooks
Random String Generator
Generate secure random passwords, API keys, and tokens with cryptographic randomness
Encrypt / Decrypt
Encrypt and decrypt data with AES, DES, Triple DES, and RC4 symmetric ciphers
What are developer tools?
Developer tools are free online programming utilities for formatting code, encoding data, and testing patterns. They cover everyday software engineering tasks such as validating and prettifying JSON for API debugging, encoding and decoding Base64 for data transport, generating cryptographic hashes for file integrity verification, testing regular expressions with live pattern matching, converting colors between HEX, RGB, HSL, and OKLCH for CSS, and encrypting and decrypting data with AES, DES, and other ciphers — all running locally in your browser with zero data transmission. These tools replace throwaway scripts and one-off converters with purpose-built interfaces that developers can rely on daily. For in-depth walkthroughs, see our guides on JSON formatting, encryption algorithms, and regular expressions.
Common use cases
API development and debugging
Format minified API responses with JSON Formatter, generate request signatures with HMAC Generator, and encode binary payloads with Base64 Encoder.
Data validation and testing
Test regular expressions against sample data, validate JSON payloads, and generate cryptographic hashes for file integrity verification.
Frontend development
Convert colors between HEX, RGB, HSL, and OKLCH for CSS, URL-encode query parameters, and convert Unix timestamps to human-readable dates for debugging.
Security and cryptography
Explore symmetric encryption with AES, DES, and Triple DES. Generate secure random strings and passwords and compute HMAC signatures for API authentication.
Tips and best practices
Validate JSON before sending API requests
Paste your JSON payload into the JSON Formatter to catch syntax errors — missing commas, unquoted keys, or mismatched brackets — before they cause cryptic API failures.
Use SHA-256 for checksums
When verifying file integrity or generating content hashes, SHA-256 from the Hash Generator is the standard choice. MD5 and SHA-1 are fine for non-security checksums but should not be used for security purposes.
Test regex patterns incrementally
Build regex patterns step by step in the Regex Tester, verifying each addition against your test string. The tool runs patterns in a protected Web Worker with a 1-second timeout, so even catastrophically backtracking patterns will not freeze your browser.
Use HMAC for API authentication
Many APIs require HMAC-signed requests. Use the HMAC Generator to verify your implementation produces the expected signature before deploying code.
Always use AES for new encryption
When encrypting data, AES-256 is the current standard. DES and Triple DES are provided for legacy compatibility and educational purposes only — never use them for new security implementations.
Quick comparison
| Algorithm | Key Size | Security | Speed | Use Case |
|---|---|---|---|---|
| AES-256 | 256-bit | Strong | Fast | Current standard |
| AES-128 | 128-bit | Strong | Fastest | General encryption |
| Triple DES | 168-bit | Moderate | Slow | Legacy systems |
| DES | 56-bit | Broken | Fast | Legacy only |
| RC4 | Variable | Broken | Very fast | Not recommended |
Frequently asked questions
Are the developer tools free?
Yes. Every developer tool on Utilavo is completely free with no accounts, subscriptions, or usage limits. All features are available without signup, and there are no premium tiers or locked capabilities. You can format JSON, encode data, generate hashes, test regex, and perform all other operations as many times as needed.
Is my data sent to a server?
No. All developer tools — JSON formatting, Base64 encoding, URL encoding, hashing, HMAC generation, regex testing, color conversion, and encryption — run entirely in your browser. Your data is never transmitted.
What developer utilities are available?
Available tools include JSON Formatter, Base64 Encoder, URL Encoder, Hash Generator, Regex Tester, Color Converter, Epoch Converter, HMAC Generator, Random String Generator, and AES/DES/Triple DES/RC4 Encrypt-Decrypt.
Do I need an account to use developer tools?
No. All developer tools work immediately in your browser without creating an account, logging in, or installing any software. Simply open any tool and start using it. Your data is processed locally on your device and is never transmitted to a server, so there is no need for authentication or registration.
What hash algorithms are supported?
The Hash Generator supports MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA-3 (256/512), BLAKE2b, BLAKE2s, BLAKE3, and RIPEMD-160. For security-sensitive hashing, use SHA-256 or BLAKE3. MD5 and SHA-1 are suitable for non-security checksums only.
What encryption algorithms are available?
The Encrypt/Decrypt hub provides AES (128/192/256-bit), DES (56-bit), Triple DES (112/168-bit), and RC4 (variable key length). AES-256 is recommended for all new applications. DES and RC4 are provided for legacy compatibility and educational purposes.
Is the Regex Tester safe to use with complex patterns?
Yes. The Regex Tester runs patterns in an isolated Web Worker thread with a 1-second timeout. Even patterns with catastrophic backtracking will be terminated automatically without freezing your browser or tab.
What color formats does the Color Converter support?
The Color Converter converts between HEX, RGB, HSL, OKLCH, and CMYK color spaces. It displays all formats simultaneously so you can copy whichever your project requires. OKLCH is the modern perceptually uniform color space used by Tailwind CSS v4.
How do I verify a file download is authentic?
Use the Hash Generator to compute the SHA-256 hash of your downloaded file, then compare it to the hash published by the source. If they match, the file is authentic and unmodified.
What is the difference between encoding and encryption?
Encoding (Base64, URL encoding) transforms data into a different format for transport but provides no security. Encryption (AES) scrambles data with a key so only authorized parties can read it.
How do I generate a secure API key or password?
Use the Random String Generator with the cryptographic preset. For API keys, use 32-64 alphanumeric characters. For passwords, enable all character sets and use at least 16 characters.
What is HMAC and when should I use it?
HMAC is a keyed-hash authentication code that verifies both data integrity and authenticity. Use the HMAC Generator to sign API requests, verify webhooks, or authenticate messages between services.