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Developer Tools for JSON, APIs, Encoding, and Debugging

Browser-local developer utilities for formatting structured data, inspecting API payloads, converting encodings, and preparing copyable debugging output.

33 live toolsPublished 2026-05-31Updated 2026-05-31Back to all tools

Quick answer

AppHelp developer tools run in the browser for fast JSON, API, encoding, hashing, JWT, cURL, GraphQL, SQL, XML, YAML, and request-inspection workflows without uploading input by default.

Workflows

Choose the right developer tool

Format and validate structured data

Use JSON, XML, YAML, GraphQL, and SQL tools to normalize payloads before sharing them in code review, docs, or support tickets.

Inspect API and auth payloads

Decode JWTs, parse user agents, inspect headers, and convert cURL commands while keeping request details local.

Convert encodings safely

Move between Base64, hex, URL encoding, Unicode escapes, and JSON string escaping for fixtures and debugging notes.

Tool list

Developer tools on AppHelp

Every listed tool opens on its own canonical AppHelp subdomain and runs in the browser with no upload by default.

JSON Formatter

Format, validate, and inspect JSON locally in the browser.

Use it for API payloads, config snippets, nested examples, and schema drafts without uploading content by default.

jsonformatvalidatedeveloper

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URL Encoder and Decoder

Encode query strings and decode URL-safe text.

A simple definition for request debugging, redirect checks, campaign links, and API query parameter cleanup.

urlencodedecodequery

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Unicode Escape Tool

Escape and unescape Unicode sequences such as \u4F60\u597D.

Use it for source code strings, JSON payloads, regex patterns, and any context that requires ASCII-safe Unicode notation.

unicodeescapeunescapeencoding

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JSON String Escape Tool

Escape and unescape JSON string content for curl, config, and logs.

Useful for embedding multiline strings in JSON config files, curl -d payloads, log entries, and debugging serialised data.

jsonescapestringdeveloper

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HTML Entity Encoder Decoder

Encode and decode common HTML entities and numeric entity references.

Essential for template authors, content editors, and developers who need safe HTML output without character encoding bugs.

htmlentityencodedecode

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QueryString JSON Converter

Convert query strings to JSON and JSON objects back to query strings.

Handy for API debugging, link sharing, form payload inspection, and converting GET parameters to structured data.

querystringjsonurlconvert

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SQL Minifier

Strip comments and collapse SQL to a single line locally.

Useful for log normalization, code-embedded queries, and quick review across MySQL, PostgreSQL, and SQL Server dialects.

sqlminifyone-linecomments

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Hex Encoder and Decoder

Convert text to hexadecimal and decode hex back to UTF-8 text locally.

Use it to inspect byte values, decode hex dumps, build hex literals for code, and debug encoding issues without uploads.

hexencodedecodeutf-8

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JWT Decoder

Decode JWT header and payload and inspect exp, iat, and nbf locally.

Use it for auth debugging and token inspection with human-readable timestamps; no secret or upload needed.

jwttokendecodeauth

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Hash Generator

Compute MD5, SHA-1, SHA-256, and SHA-512 hashes locally in the browser.

Useful for checksums, integrity checks, and fingerprinting text with Web Crypto and no upload.

hashmd5sha256checksum

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UUID Generator

Generate UUID v4 and time-ordered UUID v7 values locally.

Use it for database keys, request IDs, and seed data with bulk generation and copy.

uuidv4v7identifier

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Password Generator

Generate strong random passwords with a secure browser RNG locally.

Tune length and character classes, exclude ambiguous characters, and see a strength estimate.

passwordrandomsecuregenerator

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Regex Tester

Test regular expressions with live matches, groups, and a replace preview.

Useful for crafting patterns, inspecting capture groups, and previewing substitutions locally.

regexregexpmatchreplace

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