🇺🇸 English

95 live · 7 in development

Free AI & productivity toolkit,
100% in your browser

Count tokens, estimate API cost, build prompts, decode JWT, calculate loans, generate QR codes, run a classroom timer — no signup, no data leaves your device.

102 tools

🤖 AI / LLM 🧑‍💻 Programming / Dev 📦 Data & Time 📝 Text & Markdown 🎨 CSS & Design 🖼️ Image & Media 🇻🇳 VN & personal utilities 👩‍🏫 Classroom 💼 Jobs & Resume

🤖 AI / LLM

Token, cost, prompts, model comparison — daily LLM workflows

Token Counter

Accurate token count for ChatGPT, Claude, Gemini, Llama. Live input cost.

API Cost Calculator

Estimate monthly/yearly LLM API spend. Compare which model is cheapest.

Prompt Builder

Compose well-structured prompts. 6 templates for common tasks.

Markdown Preview

Render markdown live — paste ChatGPT/Claude output. GFM, tables, code blocks.

AI Model Comparison

GPT-5, Claude 4.7, Gemini 2.5, Llama 4, DeepSeek — context, pricing, modality (2026).

Image to Base64 Encoder

Drop image → base64 string. Includes data: URI prefix ready for Claude / GPT-4V / Gemini vision APIs.

🧑‍💻 Programming / Dev

JSON, JWT, regex, SQL, cURL, CIDR, Mermaid, commits — daily dev toolkit

JWT Decoder

Decode JWT tokens — header, payload, claims with readable timestamps.

Text Diff

Paste 2 texts → highlight diffs at word/line/char level. Great for diffing AI outputs.

JSON Schema Generator

Generate JSON Schema (Draft-07) from a sample — for LLM structured output and API validation.

JSON Formatter

Format / minify / validate JSON. Sort keys A-Z, custom indent, Ctrl+Enter shortcut.

Regex Tester

Test regex live with match highlighting. 7 ready presets including Vietnamese.

UUID / Hash / Base64 / URL

Bundle: UUID v4, SHA-256/512 hash, Base64 (URL-safe), URL encode.

Tailwind ↔ CSS Converter

Convert between Tailwind utility classes and vanilla CSS. ~200 utilities (spacing, color, flex, grid…). Helps migration.

JSONPath Tester

Test JSONPath queries against JSON samples. Pick data from API responses, debug structured output. Recursive descent + filters.

SVG to React/JSX

Convert SVG to React component. camelCase attrs, currentColor, TypeScript types, size/color props.

Markdown TOC Generator

Generate a Table of Contents from markdown. GitHub-compatible anchor links. Strip diacritics, numbered, checklist.

Number Base Converter

Convert between bases 2-36 + ASCII codes. BigInt support. Useful for bitwise debugging, CS101, memory dumps.

Mock Data Generator

Generate fake data — names, emails, phones, addresses, products. 10 locales (VN/ID/JP/KR…), JSON/CSV/SQL output.

JWT Builder (HS256)

Build & sign JWT with HMAC-SHA256 via Web Crypto API. Quick claim helpers (iat, exp). For test/dev API auth.

URL Parser & Builder

Split a URL into protocol/host/path/query/hash. Edit each query param and rebuild a clean URL.

Markdown Table Builder

Visual editor for markdown tables (GFM). Add/remove rows/cols, alignment, pretty mode balances widths.

SQL Formatter

Pretty-print SQL across 13 dialects (MySQL, PostgreSQL, BigQuery, Snowflake, MS SQL, Oracle…). UPPERCASE keywords.

JSON to TypeScript

Generate TypeScript interfaces from JSON samples. For API responses, LLM structured output, mock data.

HTTP Status Code Reference

Look up HTTP status codes 1xx-5xx. Search by number or name, click to copy. Useful for debugging APIs.

Unix Timestamp Converter

Convert Unix timestamp ↔ date. Auto-detects seconds/ms, shows local + UTC + ISO + relative time.

JSON ↔ CSV Converter

Convert JSON arrays to CSV and back. Custom delimiter, flatten nested objects.

Cron Expression Explainer

Read cron expressions in plain English + next 5 run times. For Linux cron, GitHub Actions, AWS EventBridge.

HTML Entities Encode/Decode

Encode/Decode special characters to HTML entities (< & ©...). Reference table included.

JSON ↔ YAML

Convert between JSON and YAML — auto-conversion as you type, flow style supported.

cURL ↔ fetch / axios

Convert cURL commands to fetch/axios JavaScript and back. Supports method, headers, body, query, multipart.

Regex Explainer

Break a regex into tokens and explain each — anchors, groups, quantifiers, classes. Complements Regex Tester.

CIDR / Subnet Calculator

Calculate subnet mask, network/broadcast, host range, IP count from CIDR (e.g. 10.0.0.0/24). Full IPv4 + subnetting.

Mermaid Live Editor

Mermaid editor with real-time preview — flowchart, sequence, ER, gantt, class. 6 templates, SVG/PNG export.

Conventional Commit Builder

Build Conventional Commits-compliant messages. Pick type (feat/fix/...), scope, breaking change. Preview SemVer impact.

SemVer Bump / Compare / Range

Bump versions per Semantic Versioning 2.0.0 (major/minor/patch/prerelease). Compare versions, test ranges ^/~/>=/<.

JSON Diff (structural)

Compare two JSON values structurally (key/value), independent of formatting. Shows added/removed/changed keys with JSONPath.

HMAC Signer / Webhook Verifier

Compute HMAC-SHA1/256/384/512 via Web Crypto. Presets for GitHub, Stripe, Slack — verify webhook signatures locally.

OpenAPI / Swagger Viewer

Paste OpenAPI 3.x (YAML/JSON) → view endpoints with params, body, responses, schemas. Filter by path/tag.

TypeScript → Zod Schema

Convert TS interface/type/enum to Zod runtime-validation schema. Primitives, optional, array, union, literal, enum.

.env Masker

Mask .env values before sharing — 4 modes, allowlist/blocklist, .env.example generator. Avoid secret leaks in shared logs.

YAML / JSON5 Validator

Validate YAML or JSON5 (comments, trailing commas) → strict JSON output. For GitHub Actions, K8s manifests, tsconfig.

String Escape

Encode/decode strings across 7 formats: HTML, URL, JavaScript, JSON, SQL, Base64, Shell. One-click reverse.

JSON ↔ TOML

Convert JSON ↔ TOML. For Cargo.toml, pyproject.toml, Netlify config. Two-way sync as you type.

Code Diff

Side-by-side code diff.

Markdown → HTML Export

Convert Markdown to standalone HTML for blog publishing, email, or WordPress. 3 CSS themes (GitHub, clean, none) + dark mode + .html download.

📦 Data & Time

CSV diff, time zones, working days — data & calendar utilities

Working Days Calculator

Count working days between 2 dates — exclude weekends + VN/Indonesia 2026 holidays (Lunar NY, Independence Day, Idul Fitri…).

CSV Diff

Compare 2 CSV files by key column. Detects added/removed/changed rows (which cell changed, from what to what).

World Time Zone Converter

Convert time between world cities. Auto-handles DST, shows working hours, supports 22 popular timezones.

📝 Text & Markdown

Slug, case, regex, count, sort, lorem, MD table/TOC, SQL — text utilities

Remove Vietnamese diacritics

Strip diacritics for slugs, filenames, usernames, identifiers. Optional đ → d.

URL Slug Generator

Title → SEO-clean URL slug. Strip diacritics, lowercase, custom separator.

Char / Word / Line Counter

Real-time char/word/line/paragraph count + SEO meta (60/160) and tweet (280) meters.

Password Generator

Cryptographically secure random passwords with entropy meter, custom char classes.

Text Case Converter

10 cases: UPPER, lower, Title, camelCase, snake_case, kebab-case, CONSTANT_CASE...

Lorem Ipsum (incl. Vietnamese)

Generate placeholder text — Latin / Vietnamese / Hacker speak. Optional <p> wrap.

Sort / Dedupe / Shuffle

A-Z, numeric, reverse, shuffle, dedupe — Vietnamese-aware.

Word Frequency Counter

Count word + phrase frequencies (1/2/3-gram). VN/EN stop-words, min length. For SEO keyword density, content audit.

🎨 CSS & Design

Color, gradient, shadow, animation, grid, clip-path — visual builders

Color Picker

Pick HEX/RGB/HSL, RGB sliders, 12 presets, nearest Tailwind name.

CSS Animation Builder

Visual builder for CSS animations. 10 presets (fadeIn, bounce, pulse, spin, shake…). Tweak duration, easing, iteration.

CSS Filter Builder

Visual builder for CSS filters — blur, brightness, sepia, hue-rotate, drop-shadow. 8 presets (Vintage, Polaroid, Noir…).

Color Palette Generator

Generate harmonious palettes from a base color (HSL theory). 6 schemes: Monochromatic, Analogous, Complementary, Triadic… + 10 shades.

CSS Grid Layout Generator

Visual builder for CSS Grid. 6 presets (Holy Grail, Magazine, Auto-fit…). Live preview + copy CSS.

CSS Border Radius Generator

Visual builder for border-radius — uniform, per-corner, or organic blob. 8 presets, ready-to-copy CSS.

Box Shadow Generator

Visual builder for CSS box-shadow — multi-layer, inset, opacity. 8 presets (Material, Neumorphic, Glow…).

CSS Gradient Generator

Visual builder for linear/radial/conic gradients. 8 beautiful presets, multi-color stops, ready-to-copy CSS.

WCAG Color Contrast Checker

Check contrast ratio between 2 colors against WCAG 2.1. AA/AAA results for normal + large text with live preview.

CSS Unit Converter

Convert between px / rem / em / pt / % / vw / vh. Adjustable base font-size and viewport.

Glassmorphism Generator

Visual builder for the frosted-glass effect — blur, transparency, saturation. 4 background presets, copy CSS.

CSS Loader / Spinner Generator

8 pure-CSS loader presets (ring, dots, pulse, bars, wave, orbit, flip…). Tweak size, color, speed — copy HTML+CSS.

CSS Clip-path Generator

12 shape presets (triangle, star, hexagon, speech bubble…) plus editable polygon points. Live preview, copy CSS.

🖼️ Image & Media

Compress, base64, placeholders, QR — 100% client-side

QR Code Generator

QR for URL, WiFi, vCard. Custom colors, download PNG.

Lorem Picsum URL Builder

Generate placeholder image URLs (Lorem Picsum) for mockups and prototypes. 6 ratios + 5 common sizes + grayscale + blur.

Image Compressor

Compress JPG/PNG/WebP, resize, change format — runs in-browser via Canvas API. Image is NOT uploaded anywhere.

Color Picker from Image

Drop an image and click to pick HEX/RGB/HSL. Auto-extracts dominant palette. Canvas API, no upload.

🇻🇳 VN & personal utilities

Salary, tax, loans, BMI, FX — VN-specific

VN Loan & Deposit Calculator

Deposit + loan repayment, decreasing & flat rate, full amortization.

Random Number Generator

Generate random numbers with crypto-secure or seeded PRNG. 6 presets (dice, lotto, PIN…). Unique + sort options.

Roman Numerals Converter

Convert between natural numbers and Roman numerals (1-3999). Breakdown of I/V/X/L/C/D/M composition.

VN Salary Calculator

Vietnam 2026: SI 8%, HI 1.5%, UI 1%, progressive PIT, personal + dependent deductions.

Age & Date Diff Calculator

Exact age (Y/M/D), total days lived, next birthday; or diff between 2 dates.

VND Currency Converter

Convert VND ↔ 9 currencies. Editable rates, persists locally.

BMI Calculator

BMI from height + weight, 6 WHO classes, healthy weight range.

Bill Splitter & Tip Calculator

Split a bill among people with tip, VAT, and service charge. Smart rounding for easy transfer.

Discount Calculator

Final price after a discount (% or fixed), stacked extra discount + voucher, with VAT.

Number to Words

Convert numbers to Vietnamese (mốt, tư, lăm, lẻ) or English words. Up to 999 trillion. Optional "đồng" / "VND" suffix for contracts.

TDEE / BMR Calorie Calculator

BMR (Mifflin-St Jeor) and TDEE by activity level. Calorie targets for cut/maintain/bulk + macro split (protein/carbs/fat).

Compound Interest Calculator

Compound interest growth: initial principal + monthly contributions. Year-by-year table with total interest earned.

CV Extractor (AI)

AI parses CVs into a table.

AI Email Writer

AI work email writer.

AI Product Description

AI product copy for sellers.

👩‍🏫 Classroom

Timer, attendance, group maker, grading — teacher daily tools

Random Picker

Pick a random student from a list. No-repeat mode.

Group Maker

Split a class into N balanced groups, or by group size.

Classroom Timer

Fullscreen countdown for class. Color warnings + alarm.

Pomodoro Timer

25/5/15, auto-advance, sound + notification, daily pomodoro count.

Stopwatch

Stopwatch with 10ms precision, lap recording, Space/L/R shortcuts. Great for classroom, sports.

Grade Average Calculator

Weighted average, VN-scale classification, distribution chart.

Grade Convert 10 ↔ 4 ↔ Letter

10-scale (VN) ↔ 4-scale GPA (US) ↔ letter A/B/C/D/F. Bulk convert.

Classroom Attendance

Roster management, Present/Absent/Late, notes, save sessions, CSV export.

Multiplication Table

Multiplication tables 1-20 — printable, practice mode (hide answers), quiz mode. Parents teaching kids math.

AI Quiz Generator

AI generates quizzes.

AI Lesson Plan

AI lesson plan templates.

Flashcards from text

Auto flashcards from material.

💼 Jobs & Resume

Build a CV, match your résumé against a job description (ATS) — job hunting

Resume / CV Builder

Fill a form → clean ATS-friendly CV, live preview, print / save as PDF. Autosaves in your browser, no upload.

Resume ↔ Job Description Matcher

Paste your résumé + a JD → ATS-style keyword match score, highlights missing skills before you apply.

💡

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