Start with a developer workflow, then choose the local-first tool chain that fits your API debugging, token inspection, data conversion, timestamp, cron, or Linux permission task.
Start with the task you are trying to finish, then move through related tools without leaving your browser.
Clean, validate, compare, or document API payloads.
Start here: JSON Formatter / Validator
Then use: JSON Diff, JSON to TypeScript, and URL Query Parser
Common problem solved: clean and compare API responses before filing a bug, writing tests, or documenting a sample payload.
Debug JWTs, encoded claims, URL callbacks, and token timestamps.
Start here: JWT Decoder
Then use: Timestamp Converter, Base64 Encoder / Decoder, and URL Query Parser
Common problem solved: check whether auth failures come from token expiry, issuer or audience mismatch, malformed Base64URL segments, or callback parameters.
Move data between spreadsheets, APIs, config files, and fixtures.
Start here: CSV to JSON Converter
Then use: JSON Formatter, JSON to CSV, and JSON to YAML
Common problem solved: turn spreadsheet exports into API payloads, fixtures, or config examples, then reshape the output for the next tool in the chain.
Diagnose chmod, umask, PUID/PGID, and shared-folder access before changing files.
Start here: Linux file permissions calculator
Then use: Linux umask calculator, Docker PUID/PGID guide, and Syncthing shared-folder guide
Common problem solved: identify whether an existing mode, file-creation default, container UID/GID, or shared group is blocking access.
Each tool has a focused, bookmarkable page with output you can copy immediately.
Search tools by name, workflow, or keyword. All 23 tools stay listed in the page; filtering only helps you find the right tool faster.
No matching tools. Try a broader keyword or clear the filters.
Converters for structured data, local parsing, and API handoffs.
Paste or import CSV, preview rows, infer values, and copy JSON Array or JSON Lines output without uploading your data.
Format, validate, minify, sort, and inspect JSON locally with parser errors and copy-ready output.
Compare two JSON values locally and review added, removed, changed, and unchanged fields by path.
Convert JSON arrays or objects to CSV with nested flattening, delimiter options, copy, and download output.
Convert YAML config files and snippets to formatted or minified JSON locally in your browser.
Convert JSON into readable YAML with indentation, key sorting, and copy-ready output.
Format, validate, minify, and inspect XML locally with parser errors and copy-ready output.
Focused debugging helpers for regex, local text extraction, and API workflows.
Test JavaScript regular expressions locally with match rows, capture groups, flags, and replacement preview.
Escape JSON strings for source code, logs, and tests, or unescape quoted JSON text into readable content.
Infer TypeScript interfaces from JSON samples with nested objects, arrays, optional keys, and copy-ready output.
Browser-local encoders, decoders, and identifiers for web and API workflows.
Encode URL components, decode percent-encoded text, and inspect query parameters without uploading input.
Parse URL query strings into decoded parameters, duplicate values, UTM fields, and copy-ready JSON.
Generate v4 UUIDs locally, copy or download lists, and validate UUID format for developer fixtures.
Encode and decode UTF-8 text, switch to URL-safe Base64, and convert small local files to Base64.
Decode JWT header and payload locally, inspect claims, and keep signature verification separate from decoding.
Generate SHA-256, SHA-384, SHA-512, and SHA-1 hashes locally for text or small files.
Timestamp converters for APIs, logs, Discord messages, and timezone-safe communication.
Create Discord timestamp codes for relative time, full dates, short dates, and timezone-safe event messages.
Convert Unix seconds, milliseconds, local dates, UTC strings, ISO output, and relative time labels in the browser.
Build, parse, and explain standard 5-field cron expressions locally with next run previews.
Visual CSS helpers with live previews and copy-ready output.
Design layered CSS box shadows with live preview, presets, color controls, and copy-ready CSS, Tailwind, or variable output.
Check foreground and background colors against WCAG contrast thresholds with live preview and copy-ready CSS.
Command helpers for permissions, servers, and terminal workflows.
Related tools sit close together so you can move from one task to the next without searching the whole directory.
JSON Formatter, JSON Diff, URL Query Parser, JWT Decoder, and JSON to TypeScript work together when you inspect and reshape API responses.
JWT, Base64URL, URL encoding, query parsing, and timestamps connect when you debug tokens and callback URLs.
Chmod, Umask, Docker, and Syncthing pages help you check existing modes, new-file defaults, numeric IDs, and shared-folder access.
Core conversions and calculations run in your browser, and WebUtilsLab does not save the values you enter.
Answers about privacy, bookmarking, and choosing the right tool.
WebUtilsLab is a growing collection of small local-first browser tools for developers who need quick copy-ready results.
No. The current tools are designed to open instantly and work without signup.
Yes. Tools that process pasted content do the work locally in your browser page and do not save your input.
Separate URLs make each tool easier to bookmark, share with teammates, and revisit when you need the same workflow again.