Free online developer tools

502 tools

Small utilities developers reach for daily: JSON and YAML formatters, Base64 and URL encoders, regex testers, JWT decoders, diff viewers and cron helpers. Prefer tools marked as running in your browser when you paste tokens, keys or production data, because nothing is uploaded.

Showing 73–96 of 502

0.744score
Sass Playground
Sass team
Compiles Sass or SCSS to CSS in the browser.
ArtifactNo sign-up★ 362developer tools
0.743score
WebAssembly.sh
Wasmer
Browser terminal that installs and runs WASI WebAssembly packages.
ArtifactNo sign-up★ 352developer tools
0.742score
WasmExplorer
Michael Bebenita
Compiles C and C++ to WebAssembly and shows the text format and assembly side by side.
ArtifactNo sign-up★ 338developer tools
0.741score
Kaitai Struct Web IDE
Kaitai Project
Parses binary files using a .ksy format description and shows the decoded object tree beside a hex view.
ArtifactNo sign-up★ 319developer tools
0.741score
Web Serial Terminal
Google Chrome Labs
Talks to serial devices such as Arduinos from the browser using the Web Serial API.
ArtifactNo sign-up★ 315developer tools
0.737score
SwiftFiddle
SwiftFiddle
Run and share Swift snippets in the browser.
ArtifactNo sign-up★ 275developer tools
0.731score
AsyncAPI Studio
AsyncAPI Initiative
Validates AsyncAPI documents, previews the docs and generates templates.
ArtifactNo sign-up★ 213developer tools
0.730score
WebNN Samples
W3C Web Machine Learning community
Sample apps and an expression playground for the WebNN API, which runs neural networks on device hardware from the browser.
ArtifactAINo sign-upIn-browser★ 188developer tools
0.729score
Float Toy
Evan Wallace
Interactive IEEE 754 float editor where you flip sign, exponent and mantissa bits and see the value.
ArtifactNo sign-up★ 199developer tools
0.729score
Swagger Toolbox
essuraj
Generates Swagger schema models in YAML or JSON from a sample of JSON data.
Artifact★ 261developer tools
0.728score
OCaml Playground
OCaml org
Runs OCaml in a browser toplevel with no installation.
ArtifactNo sign-up★ 193developer tools
0.726score
Decomposerize
Composerize
Converts a docker-compose file back into docker run commands.
ArtifactNo sign-up★ 172developer tools
0.721score
Tasmota Web Installer
Tasmota
Installs Tasmota firmware on ESP devices from the browser.
ArtifactNo sign-up★ 145developer tools
0.712score
First Follow
MikeDevice
Generates FIRST, FOLLOW and PREDICT sets for a grammar, to help when designing a programming language.
Artifact★ 130developer tools
0.708score
Json Formatter Live
alexandrunastase
Keyboard-driven JSON formatter and editor that works privately in the browser and can be installed as a web app.
Artifact★ 114developer tools
0.706score
Npm Unpkg
uiwjs
Browse the files inside any npm package in the browser, built on unpkg.
Artifact★ 103developer tools
0.701score
Log Voyager
hsr88
Opens and analyzes very large log files, over 10 GB, directly in the browser without uploading them.
Artifact★ 121developer tools
0.698score
Helpercraft
Helpercraft
Helps you build an Agent Skill (SKILL.md) by choosing a job, rules and a personality.
ArtifactAI★ 108developer tools
0.684score
JSONPlaceholder
typicode
Free fake REST API with posts, comments, todos and users supporting all HTTP methods.
ArtifactNo sign-up★ 5.3Kdeveloper tools
0.678score
Omatsuri
rtivital
A web app with 12 open-source tools for frontend work, such as SVG and CSS utilities.
Artifact★ 3Kdeveloper tools
0.676score
AnyCoder
akhaliq
Generates code and small apps from a prompt with a choice of models; sign in with Hugging Face.
ArtifactAI★ 3.3Kdeveloper tools
0.673score
DeepSite v4
enzostvs
Generates a web application from a text prompt through vibe coding.
ArtifactAI★ 16.6Kdeveloper tools
0.666score
GGUF My Repo
ggml-org
Converts a Hugging Face model to a quantized GGUF file and uploads it to your account; needs login.
Artifact★ 2.1Kdeveloper tools
0.661score
InstantCoder
osanseviero
Generates a small web app from a prompt and shows the result immediately.
ArtifactAINo sign-up★ 1.5Kdeveloper tools