Free Online Developer Tools for JSON, CSV, PDF, Logs & UI Work
DevToolsDesk is a collection of fast, client-side utilities for busy developers: format JSON, diff payloads, convert CSV to SQL, test regexes, decode JWTs, compress PDFs, analyze OpenTelemetry logs, build wireframes and more — without leaving your browser.
Tip: Use the search box below to jump straight to tools like “JSON formatter”, “OpenTelemetry logs”, “PDF compressor” or “Base64 encoder”.
Browse Developer Tools
Use categories or search to find what you need.🔥 Popular Tools
JSON Formatter
Format, beautify and validate JSON snippets instantly in your browser.
Multi file Diff
Compare two JSON,Yml,txt,csv files and highlight structural changes.
CSV → JSON → SQL
Convert CSV data into JSON and auto-generate SQL insert statements.
Regex Tester
Create, test and debug regular expressions with instant feedback.
JWT Decoder
Decode JWT tokens and inspect header and payload directly in-browser.
PDF → Text
Extract plain text content from PDF documents locally.
Image Compressor
Compress JPG/PNG/WebP images locally in your browser. No upload required.
UUID Generator
Generate random UUID v4 identifiers for testing and development.
JSONPath Tester
Run JSONPath expressions to query, filter and extract JSON data.
YAML ⇄ JSON ⇄ TOML
Convert between YAML, JSON and TOML formats. Auto-detect & upload supported.
.env Converter
Convert .env ↔ JSON, validate keys and detect duplicates with one click.
TOON → JSON
Convert TOON format payloads into structured, readable JSON.
cURL → Code
Convert cURL commands into code for multiple programming languages.
cURL ⇄ Postman
Convert cURL commands to Postman collections & vice-versa. Export v2.1 JSON.
OpenAPI → Code
Generate API client code from Swagger/OpenAPI specifications.
URL Tools
Encode, decode and edit URL query parameters. Convert URLs into JSON.
Cron Builder
Generate and validate cron expressions with human-readable output.
CSS Preview
Live preview HTML and CSS with responsive device views.
Wireframe Builder
Create quick UI layouts and low-fidelity wireframes directly in your browser.
Markdown Editor
Write markdown with real-time preview. Export as HTML or markdown file.
Color Tools
Pick colors, generate palettes, gradients and tints. Useful for UI/UX designers.