Free Online Tools for Everything You Do
Browse 2,706+ free interactive tools - home improvement estimators, pet calculators, cooking converters, automotive tools, finance planners, fitness calculators, developer utilities and more. No sign-up. 100% private. Runs entirely in your browser.
JSON Encode
Online JSON encoder and PHP json_encode() simulator with customizable bitmask flags (unescaped slashes, unicode, pretty print).
JSON Escape Unescape — Online JSON String Tool
Free online JSON escape/unescape tool: escape any string for embedding in JSON (minimal or full \uXXXX unicode mode) or unescape JSON strings back to raw text. 100% client-side.
JSON Feed Generator — Create JSON Feed 1.1
Free JSON Feed generator — create valid JSON Feed 1.1 online with live preview, validation, and one-click download.
Json Formatter
Format, validate, and minify JSON data.
Json Generator
JSON Key Case Converter
Recursively convert JSON property naming conventions between camelCase, snake_case, PascalCase, and kebab-case online.
JSON Key Extractor - List All Keys & Paths from JSON Online
Free JSON key extractor: list every key from nested JSON as unique names or full key paths (dot, bracket, JSONPath, Python), with counts, depth limit, and prefix filter.
JSON Linter & Validator
Professional JSON Linter, Object Validator, Syntax Error Checker, and Online JSON Corrector.
JSON Minifier & Compressor
Standalone professional JSON minifier, compressor developer utility, and payload size reducer. Compress JSON data tool with syntax validation, gzip estimation, and file export.
JSON Object Structure & CSV to JSON Formatter
Free online JSON object structure visualizer and CSV to JSON formatter. Convert CSV to JSON format, table to csv, create JSON objects, inspect JSON coding schemas, and export Java JSONObject to string.
JSON to Swift Codable Struct Generator
Interactive converter that transforms JSON payloads into idiomatic Swift Codable structs with CodingKeys.
JSON Object Viewer – Interactive Tree & JSONPath Editor
Json parse json, json object viewer, jsonpath online editor, javascript json reader, create json, what is the json format, json stringify js, convert object to array in javascript, parse string javascript, json file reader online, convert js object to array, sql json extract, parse json in node js, json tryparse javascript, javascript define json object.
JSON Online Editor, Schema Generator & JSON-LD Validator
Interactive JSON online editor, JSON Schema creator, structured data markup generator (Product, Article, LocalBusiness), and JSON-to-XML converter.
JSON Parser, Validator & String Unescape Tool
Free online JSON parse and validator tool. Escape JSON online, unescape JSON online, unescape JSON string, and C string unescape online.
Json Path Finder
JSON Prompt Generator
Interactive prompt engineering tool to generate schema-constrained JSON system prompts and structured output payloads for LLMs.
JSON REST API Mock Server
Interactive mock REST API endpoint designer, response simulator, and client code snippet generator.
JSON Schema Validator — Free Online JSON Schema Tester, Checker Playground
Free online JSON Schema validator: paste a JSON document and a schema to test validity instantly. Precise error paths (JSON Pointer), drafts 2020-12 / 2019-09 / 7, $ref, formats, YAML schemas. 100% client-side — offline & private.
JSON Schema Viewer
Interactive visual JSON Schema tree explorer, documentation viewer, and sample mock data generator online.
Json Stringify
JSON to Array JS Converter
Convert JSON objects and keys into JavaScript arrays using Object.entries, Object.values, and array transformations online.
JSON to C# Class Converter
Free online JSON to C# class converter — paste JSON and generate C# POCO models with Newtonsoft or System.Text.Json attributes, nullable types, nested classes and List<T> arrays. 100% client-side.
Json To Csv
Convert JSON arrays to CSV format.
JSON to Documentation & Word Converter
Interactive tool that converts JSON data into formatted technical documentation, Microsoft Word documents, and Markdown tables.
Json To Excel
Json To Go Struct
Json To Html
JSON to INI Converter
High-performance interactive JSON to INI Converter, INI to JSON parser, and configuration file transformer with 100% SEMrush keyword optimization.
Json To Java Pojo
JSON to JS Object & String Converter
Free online JSON to JS object converter, JSON string to JSON object parser, and JavaScript object to JSON converter. Convert JSON to JSON string and JS object to JSON.
Json To Json Schema
JSON to JSON Transformation Tool
Interactive declarative JSON mapper and schema transformer for reshaping, flattening, and restructuring JSON payloads.
JSON to JSONL Converter
Convert JSON arrays into JSON Lines (JSONL / NDJSON) and vice versa for OpenAI fine-tuning and BigQuery ingestion.
JSON to PHP Array Converter
Convert JSON strings and objects into formatted PHP associative arrays with short bracket [] or array() syntax.
JSON to Python Class Converter
Free online JSON to Python class converter — turn JSON into dataclasses, Pydantic v2 models, attrs classes or TypedDicts with live type inference. 100% client-side.
JSON to Rust Struct Converter
Free online JSON to Rust struct converter - generate serde Serialize/Deserialize structs with Option, Vec, HashMap, nested types and rename attributes. 100% client-side.
JSON to SQL Converter
Convert JSON arrays and objects into MySQL, PostgreSQL, SQLite, and SQL Server INSERT statements and DDL schemas.
Json To Table
JSON to Text Converter
Convert complex JSON documents into clean, human-readable plain text, bulleted outlines, and key-value summaries.
JSON to TOML Converter
Free online JSON to TOML converter — paste JSON or upload a .json file, get clean TOML config with tables, array tables, honest null handling, and ISO-8601 datetime detection. 100% client-side.
Json To Typescript
Json To Yaml
JSON Unstringify & Stringify Online Tool
Interactive JSON unstringify online tool, JSON unescape parser, beautifier, and multi-language object serializer for Java, Python, and JavaScript.
JSON Value Extractor — Extract All Primitive Values
Extract every primitive value from JSON online free: strings, numbers, booleans, nulls. Type filters, JSONPath locations, unique, sort, CSV/JSON export. 100% client-side.
JSON Web Signature Decode – JWS, Base64 & Multi Decoder
JSON web signature decode, base 64 converter, encodebase64 javascript, base 64 to text, b64encode online, hexadecimal reader online, converting between base 64 and base 64 url, urldecode in javascript, base64 online, how to decipher binary, base 62 encode, bash decode base64, base64 chars, convert image to base 64, bytes to text, mac decode base64, openssl base64 decode, decodebase64 java.
Article Schema Generator
High-performance Article Schema Generator and structured data markup generator for Schema.org JSON-LD Article, BlogPosting, NewsArticle, and Google News schema.
JSON-LD Event Generator
Free JSON-LD event schema generator — build Google-ready schema.org Event markup with dates, venue, tickets and organizer. Live preview, rich-result checklist, copy & download. 100% client-side.
JSON-LD Person Generator — Person Schema Markup
Generate JSON-LD markup for Persons. Free Person schema generator with live JSON-LD preview, Google checklist, copy and download.
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How to Use the Tools Directory
Every tool is a single interactive page: enter your inputs, get instant results, no account needed. Use the search box (shortcut: press /) to jump straight to a tool, or browse categories when you are exploring. Each card links to the tool's permanent URL, which you can bookmark or share.
Because all computation happens in your browser, the tools are fast, private, and free forever. If a result looks wrong, use the one-click report control on the tool page so it can be fixed.
Tool Categories at a Glance
| Category | What you will find | Example tasks |
|---|---|---|
| Developer | Encoders, formatters, regex, network tools | Format JSON, test regex, subnet a network |
| Finance | Tax, loans, salary, investing | Estimate tax brackets, amortize a loan |
| Home improvement | Estimators, measurements, materials | Size a wire, estimate paint or flooring |
| Health & fitness | Body metrics, nutrition, workouts | Track BMI, plan calories, score fitness tests |
| Math & science | Converters, geometry, statistics | Convert units, solve triangles |
| Text | Counters, sorters, generators | Count words, alphabetize a list |
| Color | Pickers, converters, checkers | Convert HEX to RGB, check contrast |
| Everyday life | Cooking, travel, automotive, pets | Convert recipes, plan fuel costs |
Popular Tasks and Where to Start
| I want to... | Start with | Why |
|---|---|---|
| Convert between number bases | Binary Converter | Step-by-step base conversion with charts |
| Validate and format data | JSON Formatter | Pretty-print and check JSON instantly |
| Count words for an essay | Word Counter | Words, characters, reading time |
| Check password strength | Password Strength Meter | Entropy-based strength scoring |
| Grade text readability | Readability Score | Flesch-Kincaid and grade levels |
| Audit color contrast | Accessibility Checker | WCAG contrast ratios in one click |
Tools Directory FAQ
What is the NRTechStudio tools directory?
It is a free catalog of more than 2,700 interactive web tools: calculators, converters, generators, and checkers for developers, finance, home improvement, health, education, and everyday tasks.
Are all the tools really free?
Yes. Every tool in the directory is free to use with no sign-up, no trial, and no paywall. They run entirely in your browser.
Do I need to create an account?
No. There are no accounts, logins, or subscriptions. Open a tool and use it immediately.
Is my data private when I use these tools?
Yes. The tools are 100% client-side: your inputs are processed by JavaScript in your own browser and never sent to a server.
How do I find the right tool?
Use the search box at the top of the directory (press / to focus it), or browse by category. Every tool card shows a short description of what it computes.
Do the tools work on mobile?
Yes. The directory and the tools use responsive layouts that adapt to phones, tablets, and desktops.
How many tools are there?
The directory holds more than 2,700 tools and grows regularly as new calculators and converters are published.
Can I request a new tool?
Yes. Each tool page has a report/feedback control you can use to request features or new tools; requests help prioritize what gets built next.
Are the tools accurate?
Calculators use published formulas and reference data (tax tables, NEC ampacity, standard conversions). Each tool page documents its method, and issues can be reported in one click for a fix.
Do tools work offline?
Once a tool page has loaded, most tools keep working without a connection because the logic is client-side JavaScript. The directory search needs the page loaded first.
What categories are covered?
Developer utilities, finance and tax, home improvement, health and fitness, math and science, text tools, color tools, networking, education, and everyday life calculators, among others.
Can I bookmark or share a tool?
Yes. Every tool has its own permanent URL under nrtechstudio.com/tools/, which you can bookmark or share directly.
Is there an API for these tools?
The tools are interactive web pages, not API endpoints. The underlying math is plain JavaScript you can inspect in the page source.
Why do some tools show ratings?
Ratings aggregate user feedback to surface the most trusted tools and flag pages that need fixes or better explanations.
How often are new tools added?
New tools are published on a continuous pipeline, prioritized by measured search demand and by user requests from the feedback controls.
Who builds these tools?
NRTechStudio, an independent tools studio focused on free, private, client-side utilities that respect user privacy.