Developer Tools
Formatters, validators, converters, and parser utilities.
Browse CategoryFast, private, ready to use
Koiloop gives developers fast, private tools for everyday data work.
Format JSON, decode JWTs, test regex, convert files, generate hashes, and clean up data without sending your input to a server. Most tools run entirely in your browser, so sensitive snippets stay on your device.
Code & Programming Utilities
Code-focused formatters, validators, analyzers, and generators.
Browse CategorySecurity & Crypto
Hashing, HMAC, JWT, and password generation tools.
Browse CategoryText & Writing
Text transform and authoring productivity helpers.
Browse CategoryText & Language
Linguistic analyzers, phonetics, and text security inspection tools.
Browse CategoryMath & Logic
Boolean logic, set operations, graph utilities, and numeric calculators.
Browse CategoryCanvas & Visual
Canvas-based generators, image analyzers, and visual experiment tools.
Browse CategoryData & Format
Binary/structured format converters and file inspection utilities.
Browse CategoryDeveloper Thinking Tools
Reasoning aides, references, snippets, and engineering writing tools.
Browse CategoryColor & Design
Contrast checks and style utility helpers.
Browse CategoryDate & Time
Timestamp conversion and date-time helper utilities.
Browse CategoryFeatured Tools
View allJSON Formatter / Validator / Minifier
Format, validate, and minify JSON content locally.
jsonformatvalidate
JWT Decoder / Encoder
Decode JWT payloads and generate unsigned or HS256 tokens.
jwttokenauth
Base64 Encode / Decode
Convert plain text to Base64 and decode Base64 back to text.
base64encoding
URL Encode / Decode
Encode URL-safe strings and decode percent-encoded values.
urlencoding
HTML Entity Encode / Decode
Encode and decode HTML entities without leaving the browser.
htmlentitiesencoding
Hash Generator (MD5 / SHA-1 / SHA-256 / SHA-512)
Generate hashes for plain text with multiple algorithms.
hashcrypto
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