# dev101.io

> Privacy-first, SEO-first, keyboard-driven hub for 50+ dev tools: format, encode, hash, diff, convert, generate, inspect — all in one place, 100% client-side.

## Overview

dev101.io is a single hub for everyday developer utilities — JSON formatting, encoding, hashing, regex, time conversions, color tools, and more. Every transform runs 100% client-side. Every tool page is SSR'd and indexed.

## Machine-readable endpoints

- [Sitemap (XML)](https://dev101.io/sitemap.xml)
- [Full content for LLMs](https://dev101.io/llms-full.txt)
- Per-tool markdown mirror: `https://dev101.io/tools/<slug>/llms.txt`

## Tools

### JSON

- [JSON Diff](https://dev101.io/tools/json-diff): Compare two JSON documents and see added, removed, and changed fields — privately.
- [JSON Escape / Unescape](https://dev101.io/tools/json-escape): Escape and unescape JSON strings in your browser — privately.
- [JSON Formatter](https://dev101.io/tools/json-format): Format, validate, and minify JSON in your browser — privately.
- [JSON Minifier](https://dev101.io/tools/json-minify): Compress JSON for production — strip whitespace, comments, and trailing commas.
- [JSONPath Evaluator](https://dev101.io/tools/json-path): Query JSON documents with JSONPath expressions — privately, in your browser.
- [JSON ↔ YAML Converter](https://dev101.io/tools/json-to-yaml): Convert JSON to YAML and YAML to JSON in your browser — privately.

### Encoding

- [Base32 Encode / Decode](https://dev101.io/tools/base32): Encode and decode Base32 strings in your browser — RFC 4648, RFC 4648-hex, and Crockford alphabets.
- [Base56 Encode / Decode](https://dev101.io/tools/base56): Encode and decode Base56 — no-confusables alphabet, safe to type by hand.
- [Base62 Encode / Decode](https://dev101.io/tools/base62): Encode and decode Base62 strings — shorter than Base64, URL-safe, UTF-8 clean.
- [Base64 Encode / Decode](https://dev101.io/tools/base64): Encode and decode Base64 strings in your browser — UTF-8 safe, privately.
- [Data URL Parser & Builder](https://dev101.io/tools/data-url): Parse, build, and inspect RFC 2397 data URLs — inline images, fonts, and text in your browser.
- [Hex Encoder / Decoder](https://dev101.io/tools/hex): Convert between text and hexadecimal in your browser — UTF-8 safe, privately.
- [HTML Entities Encode / Decode](https://dev101.io/tools/html-entities): Encode and decode HTML entities in your browser — privately.
- [URL Encode / Decode](https://dev101.io/tools/url-encode): Percent-encode and decode URLs, query params, and form values — in your browser.

### Text

- [Case Converter](https://dev101.io/tools/case-convert): Convert text between camelCase, snake_case, PascalCase, kebab-case and more — instantly.
- [CSV to JSON Converter](https://dev101.io/tools/csv-to-json): Convert CSV or TSV into JSON in your browser — RFC 4180 parser with auto-delimiter detection and type coercion.
- [Lorem Ipsum Generator](https://dev101.io/tools/lorem): Generate placeholder Lorem Ipsum text — words, sentences, or paragraphs.
- [Markdown Preview](https://dev101.io/tools/markdown-preview): Live Markdown renderer with GFM, tables, task lists, and sanitized HTML — right in your browser.
- [Slugify](https://dev101.io/tools/slugify): Convert strings to URL-safe slugs — Unicode-aware, client-side, zero deps.
- [Sort Lines](https://dev101.io/tools/sort-lines): Sort, deduplicate, trim, and reorder lines of text with natural-number and case-insensitive ordering.
- [Text Diff](https://dev101.io/tools/text-diff): Compare two texts side-by-side with line and word-level highlighting — privately.
- [Word Counter](https://dev101.io/tools/word-count): Count characters, words, lines, paragraphs, reading time.
- [XML Formatter](https://dev101.io/tools/xml-format): Format, validate, and pretty-print XML in your browser — privately.
- [YAML Formatter](https://dev101.io/tools/yaml-format): Format, validate, and lint YAML in your browser — privately.

### Time

- [Cron Expression Parser](https://dev101.io/tools/cron): Explain cron schedules and preview the next 10 runs.
- [Date Difference Calculator](https://dev101.io/tools/date-diff): Calculate the difference between two dates in every unit.
- [ISO 8601 Parser](https://dev101.io/tools/iso8601): Parse and format ISO 8601 dates, durations, and intervals.
  - [ISO 8601 Week Date Parser](https://dev101.io/tools/iso8601/week-date): Parse YYYY-Www-D week dates into a calendar date and day-of-week.
  - [ISO 8601 Ordinal Date Parser](https://dev101.io/tools/iso8601/ordinal-date): Convert YYYY-DDD ordinal (day-of-year) dates to calendar dates.
  - [ISO 8601 Duration Parser](https://dev101.io/tools/iso8601/duration): Parse P1Y2M3DT4H5M6S durations into total seconds, days, and human prose.
  - [ISO 8601 Interval Parser](https://dev101.io/tools/iso8601/interval): Parse start/end, start/duration, and duration/end intervals including repeats.
- [Timezone Converter](https://dev101.io/tools/timezone-converter): Convert between timezones with DST and multi-target support.
- [Unix Timestamp Converter](https://dev101.io/tools/unix-timestamp): Convert between Unix epoch and human-readable dates

### Crypto

- [JWT Encoder](https://dev101.io/tools/jwt-encode): Sign and encode JSON Web Tokens — HS256, HS384, HS512.
- [MD5 Hash Generator](https://dev101.io/tools/md5): Compute MD5 digests and HMAC-MD5 in your browser — pure JavaScript, no upload.
- [NanoID Generator](https://dev101.io/tools/nanoid): Generate URL-safe unique IDs with configurable length and alphabet.
- [Password Generator](https://dev101.io/tools/password-generator): Strong, random passwords and passphrases with entropy.
- [SHA-256 Hash](https://dev101.io/tools/sha256): Compute SHA-256, SHA-1, SHA-384, SHA-512 hashes in your browser — privately.
- [UUID Generator](https://dev101.io/tools/uuid): Generate UUID v1, v4, v7 — bulk and validated.

### Regex

- [Regex Explainer](https://dev101.io/tools/regex-explain): Explain Regular Expressions in plain English.
- [Regex Tester](https://dev101.io/tools/regex-tester): Test regex patterns live with groups, flags, replace.

### Network

- [DNS Lookup](https://dev101.io/tools/dns-lookup): Resolve any hostname to A, AAAA, MX, TXT, NS, CNAME, SOA, and CAA records — live, via Cloudflare DoH.
- [HTTP Status Codes](https://dev101.io/tools/http-status): HTTP Status Code Reference — search every IANA code with retry guidance.
- [IPv4 CIDR Calculator](https://dev101.io/tools/ipv4-cidr): Subnet calculator — parse CIDR, split, supernet, and test containment in your browser.
- [Is My Website Alive?](https://dev101.io/tools/is-my-website-alive): Check if a site is up in under a second — TCP handshake, HTTP status, SSL expiry, response time. No install, no account.
- [What's My IP?](https://dev101.io/tools/my-ip): See your public IP address, user agent, and connection details — instantly, no tracking.
- [URL Parser](https://dev101.io/tools/url-parser): Break URLs into parts — scheme, host, port, path, query, fragment, IDN, and PSL.
- [User Agent Parser](https://dev101.io/tools/user-agent): Parse Browser User-Agent Strings — browser, OS, device, and bot detection.

### Color

- [Color Contrast Checker](https://dev101.io/tools/color-contrast): Check WCAG 2.1 / 2.2 AA/AAA contrast and APCA Lc for any foreground/background pair — live preview, no server.
- [Color Converter](https://dev101.io/tools/color-converter): Convert a color between HEX, RGB, HSL, HSV, CMYK, OKLCH — with WCAG contrast and live swatches.

### Code

- [Chmod Calculator](https://dev101.io/tools/chmod): Unix file permissions converter — octal, symbolic, and checkbox grid, always in sync.
- [FIX Protocol Parser](https://dev101.io/tools/fix-protocol): Parse, validate, and pretty-print FIX 4.2 / 4.4 messages — checksums, body length, tag names.
- [JWT Decoder](https://dev101.io/tools/jwt-decode): Decode JSON Web Tokens — header, payload, signature.
- [MongoDB Query Builder](https://dev101.io/tools/mongo-query): Build MongoDB find() queries visually — generate shell, Node driver, Mongoose, and pymongo code in one click.
- [Number Base Converter](https://dev101.io/tools/number-base): Convert numbers between binary, octal, decimal, and hex — BigInt-safe, with bitwise ops.
- [SemVer Parser](https://dev101.io/tools/semver): Parse, compare, increment, and range-check Semantic Versioning strings.

### AI

- [Anthropic Messages API](https://dev101.io/tools/anthropic-messages): Send prompts to Claude from your browser — streaming, system prompts, your key stays local.
- [HTTP Client](https://dev101.io/tools/http-client): Send REST requests from your browser — import & export curl.
- [OpenAI Responses API](https://dev101.io/tools/openai-responses): Test OpenAI's Responses API from your browser — streaming, structured outputs, your key stays local.

## Project

- Privacy: all tools run 100% client-side. No input is recorded, logged, or sent to a server.