Free Online Developer Tools
Essential utilities for debugging APIs, formatting payloads, decoding tokens, and encoding strings. Running 100% in-browser means your sensitive credentials, database keys, and proprietary JSON payloads are never exposed to external logging servers.
Which Developer Tool Do You Need?
Debugging API Payloads?
Pretty-print minified responses, diagnose syntax errors, and minify JSON with JSON Formatter.
Open JSON FormatterInspecting Auth Tokens?
Decode JSON Web Token claims, check expiration dates, and inspect headers safely using JWT Decoder.
Open JWT DecoderEncoding & Database Keys?
Encode auth headers with Base64 Encoder, escape query parameters with URL Encoder, or generate random primary keys with UUID Generator.
Open UUID GeneratorAll Developer Tools
JSON Formatter
Format, validate, pretty-print, and minify JSON data payloads instantly in your browser.
Base64 Encoder/Decoder
Encode plain text to Base64 or decode Base64 strings safely and locally in your browser.
UUID Generator
Generate cryptographically secure, random Version 4 UUIDs (Universally Unique Identifiers) in your browser.
URL Encoder/Decoder
Encode and decode URLs and query parameters to ensure safe HTTP transmission.
JWT Decoder
Decode JSON Web Tokens (JWT) locally to inspect header and payload claims securely.
Developer Tools Standards & RFC Specifications
| Tool | Governing Standard | Security Consideration | Execution Environment |
|---|---|---|---|
| JSON Formatter | RFC 8259 | Strict quote enforcement; AST memory parsing | In-Browser V8 / JS Engine |
| JWT Decoder | RFC 7519 | Inspector only; does not require secret signing keys | In-Browser Base64URL decoder |
| UUID Generator | RFC 4122 (v4) | 122-bit CSPRNG entropy via Web Crypto | window.crypto.randomUUID() |
| URL Encoder | RFC 3986 | Percent-encodes reserved octets | In-Browser URI Encoder |
Developer Utilities Frequently Asked Questions
Is it safe to paste confidential API tokens or database dumps?
Yes. All parsing, validation, and encoding execute in your local browser sandbox. No strings or payloads are transmitted over HTTP to an AllAdvanceTools server.
Why does JSON Formatter reject trailing commas?
While JavaScript object literals tolerate trailing commas, official RFC 8259 JSON syntax strictly forbids them. Our tool enforces standard compliance so formatted payloads do not break production REST APIs.
How to Format, Validate, and Debug JSON
Read our developer guide on RFC 8259 syntax specifications, common parser errors, and in-browser payload sanitization.