Image, data and code tools
Convert images, compress photos, and format JSON online.
douni.one is a free online toolbox for image conversion, image compression, JSON formatting and data conversion. Convert WebP to JPG or PNG, prepare CSV for a spreadsheet, or generate code from structured data. Choose a tool below; no account is required.
96 tools · 10 interface languages · No registration
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Image Tool
Convert WebP files and compress images. Choose a compatible format and check transparency and quality before saving.
Merge images
Combine images into one PNG with horizontal or vertical layout, adjustable spacing and a transparent or colored background. Preview and download locally.
Flip image
Mirror a photo left to right or top to bottom and rotate it in 90° steps. Preview the result and save a PNG with transparency, entirely in your browser.
Add text to image
Add a caption to a photo using your device fonts. Set text size, color, position, opacity and outline, preview the image and download a PNG locally.
Invert colors
Invert the red, green and blue channels of a photo while preserving transparency. Preview a color negative and download the PNG without uploading.
Crop image
Crop a photo by dragging a rectangle or entering exact pixel coordinates. Preview the result and download a PNG locally.
Image mosaic
Apply a block mosaic to a rectangular part of a photo. Drag to select the region, adjust block size and preview the PNG.
SVG → PNG
Convert self-contained static SVG files into transparent PNG images. Batch conversion, output previews and ZIP downloads are supported.
Image → ICO
Convert an image into an ICO containing 16, 32, 48 and 256-pixel icons. Images are fitted proportionally with transparent padding.
JPG → WebP
Convert JPG or JPEG photos to WebP in your browser. Adjust quality, inspect previews and download files individually or as ZIP.
Resize images
Fit JPG, PNG, WebP or AVIF images inside a maximum width and height. Keep proportions and export PNG or JPG locally.
PNG → WebP
Convert static PNGs to WebP with a quality control, output previews and ZIP download. Files are processed on your device.
WebP → JPG
Convert static WebP images to JPG in your browser. Choose JPEG quality and background color, then download individual files or a ZIP.
WebP → PNG
Convert static WebP images to PNG locally in your browser. Preserve transparency and pixel dimensions, with individual and batch ZIP downloads.
AVIF → PNG
Convert static AVIF images to PNG in your browser. Preserve transparency and pixel dimensions, preview the result, and download individual images or a ZIP.
AVIF → JPG
Batch convert static AVIF images to JPG. Choose JPEG quality and a background for transparent areas, then download individual images or a ZIP.
Image → pixel art
Turn a photo into pixel art in your browser. Choose resolution, a 16-color retro or grayscale palette, and export a crisp PNG with an optional grid.
Image compression
Compress images in your browser. Adjust quality, dimensions and output format, compare file sizes, and save individual images or a ZIP.
JSON Tool
Format JSON, convert CSV and YAML, or generate types and schemas from API responses and configuration data.
JSON → CSV
Convert JSON objects to CSV locally. Select columns, flatten nested objects, choose delimiters and download UTF-8 CSV with optional BOM for Excel.
CSV → JSON
Convert CSV to JSON locally, including quoted commas and multiline cells. Read UTF-8 or Shift_JIS files and preserve leading zeros by default.
JSON → React PropTypes
Convert JSON data to React PropTypes for efficient property type checking and code reuse in React projects.
JSON → Flow
Transform JSON structures into Flow types to enhance type safety and maintainability in JavaScript code.
JSON → GraphQL
Convert JSON to GraphQL schema for simplified API development and data management.
JSON → TypeScript
Transform JSON objects into TypeScript definitions to improve type accuracy and development efficiency in TypeScript projects.
JSON → MobX-State-Tree Model
Convert JSON to MobX State Tree models for optimized state management in complex applications.
JSON → Sarcastic
Transform JSON to Sarcastic types for enhanced type checking in JavaScript projects.
JSON → io-ts
Convert JSON to io-ts types to provide robust type theory support for TypeScript projects.
JSON → Rust Serde
An online REPL for converting JSON to Rust Serde structs, simplifying data serialization in Rust projects.
JSON → Mongoose Schema
Convert JSON to Mongoose schema for rapid MongoDB data model construction.
JSON → Big Query Schema
Transform JSON to BigQuery schema for optimized big data analysis and querying.
JSON → MySQL
Convert JSON to MySQL schema for simplified database design and data management.
JSON → Scala Case Class
Transform JSON to Scala case classes to enhance code clarity and maintainability in Scala projects.
JSON → Go Struct
Convert JSON to Go structs for easy data serialization and deserialization in Go projects.
JSON → Go Bson
Transform JSON to Go Bson format for optimized BSON data handling in Go projects.
JSON → YAML
Convert JSON to YAML format for simplified configuration file management and deployment.
JSON → JSDoc
Transform JSON to JSDoc comment format to enhance code documentation and readability in JavaScript projects.
JSON → Kotlin
Convert JSON to Kotlin data classes to improve type safety and code efficiency in Kotlin projects.
JSON → Java
Convert JSON to Java classes for simplified data model construction in Java projects.
JSON → JSON Schema
Convert JSON to JSON Schema format for optimized data validation and description in APIs.
JSON → TOML
Transform JSON to TOML format for simplified configuration file authoring and maintenance.
JSON → Zod Schema
Convert JSON to Zod schema for robust data validation support in TypeScript projects.
JSON formatter
Format JSON and JSON5 in your browser, check syntax errors, and copy standard JSON. Supports comments, single quotes and trailing commas without executing JavaScript.
JSON Schema → TypeScript
Convert JSON Schema to TypeScript definitions to help developers generate type-safe interfaces and data models.
JSON Schema → OpenAPI Schema
Transform JSON Schema to OpenAPI specifications for simplified creation and maintenance of RESTful API documentation.
JSON Schema → Protobuf
Convert JSON Schema to Protobuf definitions to facilitate the construction of efficient data serialization and network communication protocols.
JSON Schema → Zod Schema
Transform JSON Schema to Zod schema for robust data validation and type safety support in TypeScript projects.
JSON-LD → N-Quads
Convert JSON-LD data to N-Quads format for efficient storage and querying of RDF data.
JSON-LD → Expanded
Transform JSON-LD to expanded form for easier understanding and analysis of RDF graphs.
JSON-LD → Compacted
Convert JSON-LD to compacted form to optimize space usage and improve data processing efficiency.
JSON-LD → Flattened
Transform JSON-LD to flattened form to simplify complex RDF structures.
JSON-LD → Framed
Convert JSON-LD to framed form for data representation in specific contexts.
JSON-LD → Normalized
Transform JSON-LD to normalized form to ensure consistency and comparability of RDF data.
HTML Tool
Work with HTML, Pug, JSX, SVG components and CSS. Translate markup and styles for your next implementation.
SVG → JSX
Efficiently convert SVG files into React JSX code, streamlining the development process for dynamic and interactive web applications.
SVG → React Native
Leverage the power of React Native with this tool that converts SVG files into React Native components, enabling cross-platform mobile app development.
HTML → JSX
Transform HTML code into React JSX format for reuse and componentization within React projects, enhancing development efficiency and code quality.
HTML → Pug
Convert HTML to Pug templates with this tool to streamline the front-end development process and improve code maintainability and efficiency.
CSS → JS Objects
Convert CSS files to JavaScript objects for easy use and manipulation of styles in front-end projects.
CSS → template literal
Transform object styles to template literals for optimized style application in frameworks like React.
CSS → TailwindCSS
Convert CSS code to TailwindCSS classes for rapidly building utility-first web designs.
Less → CSS
Convert Less preprocessor files to standard CSS, improving the compatibility and maintainability of style sheets.
Scss → CSS
Convert SCSS preprocessor files to standard CSS, simplifying the authoring and management of style sheets.
Sass → CSS
Convert Sass preprocessor files to standard CSS, enhancing the readability and reusability of style sheets.
Javascript Tool
Convert between TypeScript, JavaScript and Flow. Use the result as a starting point and verify it in your project.
JavaScript → JSON
Convert JSON5 object data to standard JSON in your browser. Supports unquoted keys, single quotes and comments; functions and JavaScript expressions are not executed.
TypeScript → Flow
Convert TypeScript code to Flow types for use in Flow projects.
TypeScript → TypeScript Declaration
Generate declaration files from TypeScript code to enhance maintainability.
TypeScript → JSON Schema
Transform TypeScript type definitions to JSON Schema for data validation and UI generation.
TypeScript → plain JavaScript
Convert TypeScript code to plain JavaScript for use in any environment.
TypeScript → Zod Schema
Convert TypeScript definitions to Zod Schema for improved type safety in data validation.
Flow → TypeScript
Convert Flow type definitions to TypeScript types, enabling the use of Flow's type safety features in TypeScript projects.
Flow → TypeScript Declaration
Transform Flow type definitions to TypeScript declaration files for improved modularity and maintainability of code.
Flow → plain JavaScript
Convert Flow code to plain JavaScript for use in environments that do not support Flow.
Graphql
Generate types and client code from GraphQL schemas as a starting point for development.
GraphQL → TypeScript
Convert GraphQL schema to TypeScript definitions for type safety and autocompletion when using GraphQL in TypeScript projects.
GraphQL → Flow
Transform GraphQL schema to Flow types for enhanced type checking and accuracy when using GraphQL in Flow projects.
GraphQL → JAVA
Convert GraphQL schema to Java classes for implementing GraphQL APIs in Java backend services.
GraphQL → Resolvers Signature
Generate GraphQL resolver signatures to simplify the implementation of server-side GraphQL logic.
GraphQL → Introspection JSON
Generate introspection JSON from GraphQL schema for easy analysis and understanding of GraphQL architecture.
GraphQL → Schema AST
Convert GraphQL schema to an AST (Abstract Syntax Tree) for schema validation and transformation.
GraphQL → Fragment Matcher
Generate utilities for matching GraphQL fragments, optimizing data queries in the frontend GraphQL usage.
GraphQL → Components
Transform GraphQL schema into reusable React components for simplifying data acquisition and presentation in the UI layer.
GraphQL → TypeScript MongoDB
Generate TypeScript-compatible GraphQL schema for MongoDB databases, optimizing data modeling and API design.
Other Tool
Convert YAML, TOML, XML and Markdown, generate QR codes, and handle other small everyday tasks.
PNG → PDF
Convert PNG images into a PDF in your browser. Reorder pages, choose A4, Letter or image size, and preserve transparent pixels without uploading your files.
Merge PDF
Combine 2–20 PDFs into one document. Reorder files before merging; page content stays as PDF rather than images.
Split PDF
Select PDF pages by preview or page range. Save the selection as one PDF or export separate PDFs with a ZIP download.
PDF → JPG
Render selected PDF pages as JPG images at 72, 150 or 300 DPI. Preview each output and download individual images or a ZIP.
Rotate PDF
Rotate selected PDF pages by 90°, 180° or 270° and download a new PDF. Preview pages and process the file locally in your browser.
Delete PDF pages
Remove unwanted pages from a PDF using visual previews or page ranges. Keep the remaining pages in order and download the PDF without uploading it.
JPG → PDF
Convert up to 20 JPG images into one PDF. Reorder photos, choose A4, Letter or image size, set margins and download locally.
XML → JSON
Convert XML files to JSON format for easier data processing and analysis.
YAML → JSON
Transform YAML files to JSON format to achieve interoperability between different data formats.
YAML → TOML
Convert YAML to TOML for creating concise and easy-to-maintain configuration files.
Markdown → HTML
Transform Markdown files into HTML for displaying formatted text content on web pages.
TOML → JSON
Convert TOML files to JSON format to expand data usage scenarios and compatibility.
TOML → YAML
Convert TOML to YAML to represent configuration data in a diverse manner.
Cadence → Go
Convert Cadence workflow descriptions to Go code for execution in Go environments.
Random Password Generator
Random password generator for creating secure passwords to protect your accounts.
QR Code Generator
Create custom QR codes for free. Generate QR codes easily in seconds.
Layout & Safe Areas
Explore screen layouts, safe areas and responsive spacing, then copy CSS for your project.
Before you start
Do my files leave my browser?
WebP conversion, image compression and JSON/CSV conversion run in your browser. Some other code converters use server processing. Check the tool description before working with confidential input.
Should I convert WebP to JPG or PNG?
Use JPG for photo compatibility, or PNG to keep a transparent background. JPG cannot store transparency. Both converters support batch processing and ZIP downloads.
What should I check when converting JSON and CSV?
Check identifiers such as 001, nested data and text encoding. JSON to CSV offers column selection and flattening; CSV to JSON supports Shift_JIS and preserving values as strings.
Which format should I choose?
WebP supports both lossy and lossless compression. A conversion changes the format; it does not restore detail already lost in the source image.
Google — WebPPNG uses lossless compression and supports an alpha channel for transparency. Choose PNG when you need to preserve a transparent background.
W3C — PNGJSON is a text format for structured data. Its values include objects, arrays, strings, numbers, booleans and null.
RFC 8259 — JSONCSV represents rows and fields as text. Fields containing commas, quotes or line breaks need quoting; a quote within a quoted field is doubled.
RFC 4180 — CSV
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