DevTools

A private, connected toolkit

Tools that pass work to each other

Forty-odd tools that hand their output straight to the next — not just for developers. Convert and compress images, edit PDFs, read QR codes, decode tokens, format data. Everything runs in your browser; nothing you paste or upload ever leaves your device.

  • 43 tools
  • 100% client-side
  • No sign-up
  • Free
One pipeline, e.g. Convert Compress Strip EXIF

Data & formats

Format, validate, convert, and query structured data.

Code Formatter

Format and beautify JSON, YAML, TOML, XML, HTML, and CSS — with JSON/CSS minify and JSON schema validation.

works well with JSON to Types

Data Diff

Compare two JSON, YAML, or TOML documents by structure, not text: added, removed, and changed values with their paths. Key order and formatting are ignored. Runs in your browser.

works well with Code Formatter

HAR Viewer

Open a .har network export and explore its requests, sizes, status codes, and a timing waterfall — entirely in your browser. Nothing is uploaded.

works well with URL Inspector

JSON ↔ YAML ↔ TOML

Convert structured data between JSON, YAML, and TOML, live in your browser.

works well with JSON to Types

JSON to SQL

Infer a SQL CREATE TABLE from a JSON sample or a JSON Schema — column types, nullability, and a primary-key guess — for PostgreSQL, MySQL, or SQLite. Runs in your browser.

works well with JSON to Types

JSON to Types

Turn a JSON sample or a JSON Schema into TypeScript, Zod, Go structs, Python dataclasses, Kotlin data classes, or Java records/Lombok. Infers optional and nullable fields. Runs in your browser.

works well with JSON to SQL

JSONPath Tester

Query JSON live with JSONPath — filter, slice, and recurse, and see each matched value with its path, all in your browser.

works well with Code Formatter

Log & Trace Analyzer

Open a huge log file — JSON/NDJSON, logfmt, syslog, or Java/app-server text — and get instant time-range narrowing, faceting, a timeline, request tracing, and full-text search, entirely in your browser with nothing uploaded.

XPath Tester

Test XPath expressions against XML or HTML live — see matched nodes, their location paths, and string/number/boolean results, all in your browser.

works well with Code Formatter

Security & privacy

Debug tokens, decode certificates, and check files for hidden data.

ASN.1 Decoder

Decode ASN.1 DER/BER — paste PEM, Base64, or hex and see the tag–length–value tree behind X.509 certificates, keys, and CMS, entirely in your browser.

Certificate Decoder

Decode X.509 / PEM certificates — view subject, issuer, validity, SANs, key, and fingerprints, all in your browser.

works well with JWT Debugger

Hash Generator

Compute MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes of text or a file, plus HMAC — all at once, entirely in your browser.

works well with Encoder / Decoder

JWT Debugger

Decode and inspect JSON Web Tokens: view the header and payload, check expiry, and verify HS/RS/PS/ES signatures — all in your browser.

works well with JWT Signer

JWT Signer

Build a JWT header and payload and sign it with HMAC (HS256/384/512) or an RSA/ECDSA private key (RS/PS/ES) — entirely in your browser. Nothing is uploaded.

works well with JWT Debugger

Metadata Inspector

Inspect the hidden metadata in a photo or document — EXIF, GPS location, author, dates, and more — right in your browser. Download a cleaned copy with the metadata removed.

works well with Metadata Stripper

Metadata Stripper

Strip EXIF, GPS, author, and hidden metadata from images and documents in one batch — locally in your browser. JPEG, PNG, WebP, GIF, PDF, Office, OpenDocument & EPUB.

works well with Metadata Inspector

Password Hash Generator

Hash a password with Argon2id, bcrypt, scrypt, or PBKDF2 — with OWASP-recommended parameters — and verify a password against a hash, entirely in your browser.

PDF Redactor

Redact a PDF so the text is permanently removed, not just covered — and strip its hidden metadata, comments, and attachments. Entirely in your browser, nothing uploaded.

Text

Search, transform, and compare text and code.

Case Converter

Convert text between camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Title Case, and more — all at once, in your browser.

Diff Viewer

Compare two texts or code snippets side by side with line-level difference highlighting.

works well with Data Diff

Image to Text (OCR)

Extract the text from a screenshot, photo, or scanned document with OCR — in 18 languages, entirely in your browser. Nothing is uploaded.

Markdown Editor

Write Markdown with a live GitHub-flavored preview, a table of contents, and one-click export to Markdown or HTML — entirely in your browser, nothing uploaded.

Mojibake Fixer

Repair garbled text where UTF-8 was misread as Windows-1252 — turn “café” back into “café” and “’” back into “’”. Runs entirely in your browser.

works well with Encoder / Decoder

Regex Railroad Diagram

Visualize a regular expression as a railroad diagram and read a plain-English, step-by-step explanation. Hover to link the two. Runs in your browser.

works well with Regex Tester

Regex Sample Generator

Generate example strings that match a regular expression, then send them straight into the Regex Tester. Every sample is verified to match — all in your browser.

works well with Regex Tester

Regex Tester

Build and test regular expressions live — highlight matches, inspect capture groups, and preview replacements.

works well with Regex Railroad Diagram

URL Inspector

Break a URL into its parts and an editable query-string table, then rebuild it. Decodes parameters and exports them as JSON. Runs in your browser.

works well with Encoder / Decoder

Converters

Convert values, images, and files between formats and representations.

Code to UML

Turn TypeScript or Java source into a Mermaid class diagram — classes, interfaces, enums, fields, methods, inheritance, and interfaces — rendered live in your browser.

works well with UML to Code

Color Converter

Convert colors between HEX, RGB, HSL, HSV, and OKLCH, with a picker, alpha, and a WCAG contrast checker — all in your browser.

works well with CSS Unit Converter

CSS Unit Converter

Convert between CSS units — px, rem, em, pt, vw, vh, and more — with live visual feedback and a full conversion table.

works well with Color Converter

Encoder / Decoder

Encode and decode text with Base64, URL, and Hex — UTF-8 safe, instant, and fully in your browser.

works well with Hash Generator

HEIC to JPG Converter

Convert iPhone HEIC/HEIF photos to JPG, PNG, or WebP — fast, multi-threaded batch conversion entirely in your browser. Nothing is uploaded, and location and metadata are removed by default.

Image Compressor

Fast, multi-threaded image compression — shrink many images at once by quality or to a target file size, with WebP/JPEG output and optional resizing, entirely in your browser.

Image Converter

Convert, resize, and compress images between PNG, JPEG, and WebP, or copy them as a Base64 data URI — entirely in your browser.

works well with Metadata Inspector

Timestamp Converter

Convert between Unix epoch time and human-readable dates — seconds, milliseconds, ISO 8601, UTC, time zones, and relative time.

works well with URL Inspector

UML to Code

Turn a Mermaid class diagram into TypeScript, Python, Java, or C# code — classes, interfaces, enums, inheritance, and relationships — live in your browser.

works well with Code to UML

Built to chain

Tools that hand work to the next

Most tool sites are a drawer of disconnected boxes. Here a tool's result flows straight into the next — no copy-paste, no re-uploading, and never off your device.

01

Do the task

Format, decode, convert, compress — whatever the job needs, in a focused tool.

02

Send it onward

“Send to →” hands the result to a suggested next tool in one click — no copy-paste.

03

Never leaves your device

The whole pipeline runs locally in your browser. Nothing is uploaded.

Why it's different

Small tools, done right

Focused utilities that each do one job well — with the polish of a proper code editor and none of the privacy trade-offs of typical online tools.

Powered by the Monaco editor

Wherever a tool edits code or data, its editor is Monaco — the same one that powers VS Code — so you get real syntax highlighting, bracket matching, inline error markers, multi-cursor editing, find-and-replace, and keyboard shortcuts you already know. Working with JSON, YAML, XML, or a regular expression feels like working in your IDE, right in the browser.

Private by design

Every tool runs entirely on your device using client-side JavaScript. The text you paste, the files you drop, and the tokens you decode are never uploaded to a server — there is no backend to send them to.

Instant and offline-friendly

With no network round-trips, results appear as you type. Once a tool has loaded it keeps working without a connection, so it is just as useful on a plane or a locked-down network.

Free, no sign-up

No accounts, no paywalls, no usage limits. Open a tool and start working. The site is supported by unobtrusive advertising so the tools stay free for everyone.

Under the hood

A real editor, not a plain text box

Most online developer tools drop your input into a bare textarea. These don't. Wherever a tool edits code or data, its editor is Monaco, the open-source editor that powers Visual Studio Code, so the moment you paste a payload you get syntax highlighting, bracket and tag matching, code folding, and inline markers that point at the exact line of a problem.

Familiar shortcuts work too — multi-cursor selection, find and replace, and select-all-occurrences — which makes fixing a malformed JSON document or tweaking a regular expression far quicker than in a plain field.

That editor sits on top of tools that handle the awkward real-world cases: UTF-8 and binary data, large inputs, and malformed content that should fail with a clear message rather than silently producing the wrong result. Whether you're decoding a JWT, comparing two config files, formatting an API response, converting between JSON, YAML, and TOML, or inspecting an X.509 certificate, the goal is the same — fast, accurate, and readable.

Everything runs client-side, so none of that data leaves your browser. There are no accounts to create and nothing to install; open a tool and start working. Learn more about how it works.

Questions

Frequently asked questions

Are these developer tools free?+

Yes — every tool is completely free, with no account, sign-up, or usage limit. The site is supported by unobtrusive advertising so the tools stay free.

Is my data private?+

Yes. Every tool runs entirely in your browser using client-side JavaScript. The text you paste, the files you drop, and the tokens you decode are never uploaded to any server.

Do I need to create an account?+

No. There is nothing to sign up for and nothing to install — open a tool and start using it.

Do the tools work offline?+

Mostly. Once a tool has loaded it keeps working without a connection, since all processing happens on your device.

Can I chain tools together?+

Yes. Where it makes sense, a tool shows a “Send to…” button that hands its output to another tool — for example decoding a Base64 image and inspecting its EXIF metadata, turning a JWT payload into a JSONPath query, or converting YAML to JSON and generating types from it. It all stays in your browser.

Can I suggest a new tool?+

Absolutely — many tools started as user requests. Head to the Contact page and send your idea our way.