# Claude skills, kits, prompts and guides

> Skills for Claude, local kits for Claude Code (videos, carousels), prompts, templates and free guides, plus free browser tools. New every week.

Canonical: https://nexin.si/library

Library

Skills that teach Claude a method, kits that make Claude Code produce videos and carousels on your computer, prompts, templates and free guides, plus free browser tools that never upload your files. New ones every week.

KIT SOCIAL MEDIA

### [Carousel Kit](https://nexin.si/library/carousel-kit)

A carousel maker you open in Claude Code: it writes the slides, renders ready-to-post PNGs and a LinkedIn PDF on your computer, then checks every slide.

GUIDE CLAUDE · FREE

### [Claude Code Skills](https://nexin.si/library/claude-code-skills)

What Claude Code skills are, where SKILL.md lives, how Claude picks one up, and how to write, bundle and test your first skill step by step.

GUIDE CLAUDE · FREE

### [Claude Code for Marketing](https://nexin.si/library/claude-code-for-marketing)

How marketers and founders use Claude Code for content repurposing, landing page edits, SEO audits, carousels, promo videos and CSV reports, with prompts.

KIT SOCIAL MEDIA

### [Video Kit](https://nexin.si/library/video-kit)

Turn HTML to video with Claude Code: it writes animated scenes in GSAP, checks stills, fixes them and renders a 1080p MP4 on your own computer.

GUIDE CLAUDE · FREE

### [What Can Claude Code Do?](https://nexin.si/library/what-can-claude-code-do)

Real Claude Code use cases beyond writing code, from tests and docs to data cleanup, videos, carousels, reports and chores, each with a prompt to copy.

TOOL PRODUCTIVITY · FREE

### [Acres to Hectares](https://nexin.si/library/acres-to-hectares)

Convert acres to hectares as you type, both ways, with the exact 0.40468564224 factor, a swap button and a table of common land areas. Runs in your browser.

PROMPT BUSINESS

### [Acronym Generator](https://nexin.si/library/acronym-generator)

Creates acronyms and backronyms for a project, team or program, puts pronounceable ones first and checks letter by letter that each one spells its expansion.

TOOL SOCIAL MEDIA · FREE

### [Add Text to Image](https://nexin.si/library/add-text-to-image)

Add text to an image in a bold font, pick the size and color, add an outline, and click where it goes. Save as PNG, JPG or WebP. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Age Calculator](https://nexin.si/library/age-calculator)

Enter a date of birth to get the exact age in years, months and days, the total in months, weeks and days, the weekday of birth and the next birthday.

PROMPT WRITING

### [Apology Letter](https://nexin.si/library/apology-letter)

Writes a personal or professional apology letter that names what happened, owns it without excuses, shows the impact on them and says what will change.

TOOL PRODUCTIVITY · FREE

### [BMI Calculator](https://nexin.si/library/bmi-calculator)

Enter your height and weight in metric or US units to get your BMI, the WHO adult category and the healthy weight range for your height.

TOOL PRODUCTIVITY · FREE

### [Binary Translator](https://nexin.si/library/binary-translator)

Translate text to binary and binary back to text as you type, as UTF-8 bytes in 8-bit groups, so accents and emoji work. Nothing is uploaded.

PROMPT SOCIAL MEDIA

### [Bio Generator](https://nexin.si/library/bio-generator)

Writes your bio in one-liner, short and long versions, first or third person, for LinkedIn, Instagram, a website or a speaker intro, from your real background.

TOOL PRODUCTIVITY · FREE

### [Blur Image](https://nexin.si/library/blur-image)

Blur an image, or only a face, a license plate or an address you select, with a strength slider. Save as PNG, JPG or WebP. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [CM to Feet](https://nexin.si/library/cm-to-feet)

Convert cm to feet as you type, both ways, with the exact 30.48 cm factor, a swap button and a table of common values. Handy for heights; runs in your browser.

TOOL PRODUCTIVITY · FREE

### [CSV to JSON](https://nexin.si/library/csv-to-json)

Convert CSV to JSON as you type, with commas, semicolons or tabs detected, quoted fields handled and numbers kept as numbers. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Coin Flip](https://nexin.si/library/coin-flip)

Flip one coin for heads or tails, or up to 1,000 coins at once with a count of each. Uses your browser's secure random generator, nothing sent.

TOOL PRODUCTIVITY · FREE

### [Color Palette Generator](https://nexin.si/library/color-palette-generator)

Generate a color palette from one color: shades, complementary, analogous, triadic, tetradic or monochrome, with HEX codes to copy. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Color Picker](https://nexin.si/library/color-picker)

Pick a color and get its HEX, RGB, HSL and CMYK, its contrast with white and black, and lighter and darker shades. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Crop Image](https://nexin.si/library/crop-image)

Crop an image by dragging a selection, any shape or locked to 1:1, 4:3, 3:2, 16:9, 9:16 or 4:5, then save it as PNG, JPG or WebP. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Cups to ML](https://nexin.si/library/cups-to-ml)

Convert US cups to ml as you type, both ways, with the exact 236.5882365 ml cup, tbsp and tsp in the list and a table of common amounts. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Date Calculator](https://nexin.si/library/date-calculator)

Add or subtract days, weeks, months or years from a date and get the new date and its weekday, or count the days between two dates, in your browser.

TOOL PRODUCTIVITY · FREE

### [Days Between Dates](https://nexin.si/library/days-between-dates)

Count the days between two dates: days, weeks and days, years, months and days, and weekdays, with an option to count the end date too. In your browser.

TOOL PRODUCTIVITY · FREE

### [Delete Pages from PDF](https://nexin.si/library/delete-pages-from-pdf)

Delete pages from a PDF by listing them, like 2, 5-7, and download a new PDF without them. It runs in your browser, so your file is never uploaded.

TOOL PRODUCTIVITY · FREE

### [Dice Roller](https://nexin.si/library/dice-roller)

Roll up to 100 dice at once, d4, d6, d8, d10, d12, d20 or d100, and see each roll and the total. Uses your browser's secure random generator.

TOOL PRODUCTIVITY · FREE

### [Diff Checker](https://nexin.si/library/diff-checker)

Check the diff between two versions of code, config or logs line by line, with line numbers and added and removed counts. It runs in your browser.

SKILL PRODUCTIVITY

### [Email Writer](https://nexin.si/library/email-writer)

A skill for Claude that writes any work or personal email from a few notes or a thread: subject line, the right tone, one clear ask and a shorter version.

TOOL PRODUCTIVITY · FREE

### [Fahrenheit to Celsius](https://nexin.si/library/fahrenheit-to-celsius)

Convert Fahrenheit to Celsius as you type, both ways, with the formula on screen, Kelvin too and a table from -40 to 100. Runs in your browser.

PROMPT WRITING

### [Farewell Message](https://nexin.si/library/farewell-message)

Writes farewell messages for a coworker, a boss, a team or your own exit, as a card note, an email or a short speech, in a warm, funny or formal tone.

TOOL PRODUCTIVITY · FREE

### [Feet to CM](https://nexin.si/library/feet-to-cm)

Convert feet to cm as you type, both ways, with the exact 1 ft = 30.48 cm factor, a swap button and a table of common values. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Feet to Meters](https://nexin.si/library/feet-to-meters)

Convert feet to meters as you type, both ways, with the exact 1 ft = 0.3048 m factor, a swap button and a table of common lengths. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Flip Image](https://nexin.si/library/flip-image)

Flip an image upside down, or mirror it left to right, in one click at full resolution, then save it as PNG, JPG or WebP. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [GPA Calculator](https://nexin.si/library/gpa-calculator)

Enter a letter grade and credits for each course to get your GPA on the 4.0 scale, weighted by credits, with your total credits and grade points.

TOOL PRODUCTIVITY · FREE

### [Gallons to Liters](https://nexin.si/library/gallons-to-liters)

Convert US gallons to liters as you type, both ways, with the exact 3.785411784 factor, the UK gallon in the list and a table of common volumes.

SKILL WRITING

### [Grammar Checker](https://nexin.si/library/grammar-checker)

A skill for Claude that proofreads your text for grammar, spelling and punctuation, keeps your voice and lists every change with a short reason.

TOOL PRODUCTIVITY · FREE

### [Grams to Oz](https://nexin.si/library/grams-to-oz)

Convert grams to ounces as you type, both ways, with the exact 28.349523125 g factor, a swap button and a table of common weights. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Grayscale Image](https://nexin.si/library/grayscale-image)

Turn an image black and white, all of it or only an area you select, at full resolution, then save it as PNG, JPG or WebP. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [HEX Color Picker](https://nexin.si/library/hex-color-picker)

Pick a color and copy its HEX code, or paste a HEX code to get RGB, HSL, CMYK, contrast ratios and shades. It runs in your browser, nothing uploaded.

PROMPT SOCIAL MEDIA

### [Hashtag Generator](https://nexin.si/library/hashtag-generator)

Writes hashtags for one post per platform (Instagram, TikTok, LinkedIn, X), mixing broad, niche and specific tags in the number you choose.

TOOL PRODUCTIVITY · FREE

### [Image Color Picker](https://nexin.si/library/image-color-picker)

Pick colors from an image: click any pixel for its HEX, RGB and HSL, and see the 6 main colors of the picture. It runs in your browser, nothing uploaded.

TOOL PRODUCTIVITY · FREE

### [Image Cropper](https://nexin.si/library/image-cropper)

An image cropper with ratio presets (1:1, 4:3, 3:2, 16:9, 9:16, 4:5) or free selection, full resolution up to 8000 px, and undo. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Image to Text](https://nexin.si/library/image-to-text)

Extract text from screenshots, photos and scans with OCR, then edit, copy or download it as .txt. It runs in your browser, so your images are never uploaded.

TOOL PRODUCTIVITY · FREE

### [Inches to CM](https://nexin.si/library/inches-to-cm)

Convert inches to cm as you type, both ways, with the exact 1 in = 2.54 cm factor, a swap button and a table of common values. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Inches to MM](https://nexin.si/library/inches-to-mm)

Convert inches to mm as you type, both ways, with the exact 25.4 factor, a swap button and a table of common values. It runs in your browser, nothing sent.

PROMPT SOCIAL MEDIA

### [Instagram Caption Generator](https://nexin.si/library/instagram-caption-generator)

Writes Instagram captions from your photo, voice and goal, with a hook first line, a short body, a question or CTA and a few hashtags, in three lengths.

PROMPT BUSINESS

### [Interview Questions](https://nexin.si/library/interview-questions)

Predicts the interview questions for your role and level, explains what each one tests, outlines answers from your real experience and adds questions to ask.

TOOL PRODUCTIVITY · FREE

### [Invert Colors](https://nexin.si/library/invert-colors)

Invert colors in an image, all of it or only an area you select, to make a negative or flip a light screenshot to dark. Save as PNG, JPG or WebP.

TOOL PRODUCTIVITY · FREE

### [JSON to CSV](https://nexin.si/library/json-to-csv)

Convert JSON to CSV as you type, with nested objects as dotted columns and proper quoting for commas and line breaks. It runs in your browser, nothing uploaded.

TOOL PRODUCTIVITY · FREE

### [KM to Miles](https://nexin.si/library/km-to-miles)

Convert km to miles as you type, both ways, with the exact 1.609344 factor, a swap button and a table of common distances. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [KM/H to MPH](https://nexin.si/library/kmh-to-mph)

Convert km/h to mph as you type, both ways, with the exact 1.609344 factor, m/s and knots in the list and a table of common speeds. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Lbs to Kg](https://nexin.si/library/lbs-to-kg)

Convert lbs to kg as you type, both ways, using the exact 0.45359237 factor, with a swap button and a table of common weights. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Liters to Gallons](https://nexin.si/library/liters-to-gallons)

Convert liters to US gallons as you type, both ways, with the exact 3.785411784 factor, the UK gallon in the list and a table of common volumes.

TOOL BUSINESS · FREE

### [Loan Calculator](https://nexin.si/library/loan-calculator)

Enter the loan amount, annual interest rate and term in years to get the monthly payment, the number of payments, the total interest and the total paid.

TOOL PRODUCTIVITY · FREE

### [ML to Oz](https://nexin.si/library/ml-to-oz)

Convert ml to US fluid ounces as you type, both ways, with the exact 29.5735 ml factor, a swap button and a table of common volumes. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [MM to Inches](https://nexin.si/library/mm-to-inches)

Convert mm to inches as you type, both ways, with the exact 25.4 factor, a swap button and a table of common sizes. It runs in your browser, nothing sent.

TOOL PRODUCTIVITY · FREE

### [MPH to KM/H](https://nexin.si/library/mph-to-kmh)

Convert mph to km/h as you type, both ways, with the exact 1 mph = 1.609344 km/h factor, m/s and knots in the list and a table of common speeds.

SKILL MARKETING

### [Marketing Plan Writer](https://nexin.si/library/marketing-plan-writer)

A skill for Claude that writes a 90-day marketing plan from your product, buyer, budget and numbers: goals, channels, a weekly calendar, budget and metrics.

TOOL SOCIAL MEDIA · FREE

### [Meme Generator](https://nexin.si/library/meme-generator)

Make a meme from your own image or a plain background, with classic white outlined top and bottom text, then download it as a PNG. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Meters to Feet](https://nexin.si/library/meters-to-feet)

Convert meters to feet as you type, both ways, with the exact 0.3048 factor, a swap button and a table of common lengths. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Mic Test](https://nexin.si/library/mic-test)

Test your microphone in the browser with a live level in dB, the loudest level, and a 5-second recording to play back. Nothing is saved or sent.

TOOL PRODUCTIVITY · FREE

### [Miles to KM](https://nexin.si/library/miles-to-km)

Convert miles to km as you type, both ways, with the exact 1 mi = 1.609344 km factor, a swap button and a table of common distances. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Mirror Image](https://nexin.si/library/mirror-image)

Mirror an image left to right in one click, fix a reversed selfie or point a photo the other way, then save as PNG, JPG or WebP. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Morse Code Translator](https://nexin.si/library/morse-code-translator)

Translate text to Morse code and Morse back to text as you type, with letters, digits and punctuation. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [Oz to Grams](https://nexin.si/library/oz-to-grams)

Convert oz to grams as you type, both ways, with the exact 1 oz = 28.349523125 g factor, a swap button and a table of common weights. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Oz to ML](https://nexin.si/library/oz-to-ml)

Convert US fluid oz to ml as you type, both ways, with the exact 29.5735295625 factor, a swap button and a table of common sizes. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [PDF to Text](https://nexin.si/library/pdf-to-text)

Extract the text from every page of a PDF, with page markers if you want them, then copy it or download a .txt file. It runs in your browser, nothing uploaded.

TOOL PRODUCTIVITY · FREE

### [PDF to Word](https://nexin.si/library/pdf-to-word)

Turn a PDF into an editable Word .docx with the text paragraph by paragraph and a page break per page. It runs in your browser, so the PDF is never uploaded.

SKILL BUSINESS

### [PRD Writer](https://nexin.si/library/prd-writer)

A skill for Claude that writes a product requirements document from an idea or notes: problem, users, goals, metrics, prioritized requirements and edge cases.

TOOL PRODUCTIVITY · FREE

### [Percentage Calculator](https://nexin.si/library/percentage-calculator)

Work out X% of Y, what percent one number is of another, or the percentage change between two numbers. Results update as you type, in your browser.

SKILL BUSINESS

### [Performance Review Writer](https://nexin.si/library/performance-review-writer)

A skill for Claude that writes manager reviews and self evaluations from your notes: strengths, impact with evidence, fair growth areas and next goals.

TOOL PRODUCTIVITY · FREE

### [Pixelate Image](https://nexin.si/library/pixelate-image)

Pixelate an image, or only a face, a name or a plate you select, with a slider for block size. Save as PNG, JPG or WebP. It runs in your browser.

PROMPT MARKETING

### [Podcast Name Generator](https://nexin.si/library/podcast-name-generator)

Writes podcast name ideas from your topic, audience, host and tone, grouped by style, with taglines for the top picks and a checklist before you commit.

PROMPT WRITING

### [Poem Generator](https://nexin.si/library/poem-generator)

Writes a poem on your topic in the form you choose, from haiku and sonnet to limerick or free verse, keeping the meter and rhyme, then offers a revision.

SKILL MARKETING

### [Press Release Writer](https://nexin.si/library/press-release-writer)

A skill for Claude that writes an AP-style press release from your facts: headline, dateline, lede, body, approved quotes, boilerplate and media contact.

TOOL PRODUCTIVITY · FREE

### [Random Name Picker](https://nexin.si/library/random-name-picker)

Paste up to 200 names, one per line, and spin to pick one at random for a class, a team or a giveaway. Remove each winner to draw the next fairly.

TOOL PRODUCTIVITY · FREE

### [Random Number Generator](https://nexin.si/library/random-number-generator)

Pick random numbers between a minimum and a maximum, up to 1,000 at once, with or without repeats. Uses your browser's secure random generator.

TOOL PRODUCTIVITY · FREE

### [Regex Tester](https://nexin.si/library/regex-tester)

Test JavaScript regular expressions live, with highlighted matches, numbered and named groups, flags and replace. It runs in your browser, nothing uploaded.

TOOL WRITING · FREE

### [Reverse Text](https://nexin.si/library/reverse-text)

Reverse text by letters, by word order or by line order, with emoji and accented letters kept whole. It runs in your browser, so nothing is uploaded.

PROMPT WRITING

### [Rhyme Generator](https://nexin.si/library/rhyme-generator)

Finds rhymes for any word, perfect, near and multisyllabic, grouped by syllable count, and fits them into a lyric or poem line you give, with accent notes.

TOOL PRODUCTIVITY · FREE

### [Roman Numerals Converter](https://nexin.si/library/roman-numerals-converter)

Convert numbers from 1 to 3999 to Roman numerals and back, one per line, with invalid numerals like IIII caught and corrected. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Rotate Image](https://nexin.si/library/rotate-image)

Rotate an image 90° left or right, or 180° in two clicks, to fix sideways phone photos and scans, then save as PNG, JPG or WebP. Runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Rotate PDF](https://nexin.si/library/rotate-pdf)

Rotate PDF pages 90° clockwise, 180° or 90° counterclockwise, all of them or only the pages you list, into one new PDF. Nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [SHA256 Hash Generator](https://nexin.si/library/sha256-hash)

Generate a SHA-256 hash of any text as you type, plus SHA-1, SHA-384 and SHA-512, in hex with an uppercase option. It runs in your browser.

PROMPT PRODUCTIVITY

### [SMART Goals](https://nexin.si/library/smart-goals)

Turns a vague goal into SMART goals that are specific, measurable, achievable, relevant and time-bound, with milestones and a first step for this week.

PROMPT WRITING

### [Sentence Rewriter](https://nexin.si/library/sentence-rewriter)

Rewrites a sentence or paragraph in five versions, shorter, clearer, formal, friendly and simpler, keeping your meaning and explaining every change.

PROMPT MARKETING

### [Slogan Generator](https://nexin.si/library/slogan-generator)

Writes short slogans and taglines for your brand or product, grouped by angle, flags the generic ones and reminds you to check trademarks before you use one.

TOOL PRODUCTIVITY · FREE

### [Split PDF](https://nexin.si/library/split-pdf)

Split a PDF into one file per page, one file per page range, or pull chosen pages into one new file. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [Square Feet to Square Meters](https://nexin.si/library/square-feet-to-square-meters)

Convert square feet to square meters as you type, both ways, with the exact 0.09290304 factor, a swap button and a table of common floor areas.

PROMPT WRITING

### [Story Generator](https://nexin.si/library/story-generator)

Writes a short story from your idea with the genre, length, audience and point of view you pick, with a title, clear scenes, a real ending and sequel ideas.

TOOL WRITING · FREE

### [Text Compare](https://nexin.si/library/text-compare)

Compare two texts line by line as you type, with added lines highlighted, removed lines struck through and line numbers. It runs in your browser.

TOOL PRODUCTIVITY · FREE

### [Text to Speech](https://nexin.si/library/text-to-speech)

Hear any text read aloud with the voices on your device, with speed from 0.5x to 2x, pitch, pause and stop. It runs in your browser and makes no audio file.

PROMPT WRITING

### [Thesis Statement Generator](https://nexin.si/library/thesis-statement-generator)

Helps sharpen your thesis statement from your topic, essay type, position and reasons: several options, why each works, a stronger revision and an outline.

TOOL PRODUCTIVITY · FREE

### [Tip Calculator](https://nexin.si/library/tip-calculator)

Enter the bill, the tip percentage and how many people are paying to get the tip, the total and each person's share, rounded to cents.

PROMPT SOCIAL MEDIA

### [Username Generator](https://nexin.si/library/username-generator)

Generates usernames from your interests, name and vibe, fitted to each platform's length and character rules, with variations to try if one is taken.

TOOL PRODUCTIVITY · FREE

### [Webcam Test](https://nexin.si/library/webcam-test)

Test your webcam in the browser with a live preview, the resolution and frame rate it reports, a mirror switch and a photo to download as PNG.

PROMPT WRITING

### [Wedding Speech](https://nexin.si/library/wedding-speech)

Writes a wedding speech for your role, best man to parent, from your real stories, timed to the minutes you have, with a toast and delivery notes.

TOOL PRODUCTIVITY · FREE

### [Wheel Spinner](https://nexin.si/library/wheel-spinner)

Type up to 200 options, one per line, and spin the wheel to pick one. The winner is drawn with secure random, and you can remove it after each spin.

TOOL PRODUCTIVITY · FREE

### [Word to PDF](https://nexin.si/library/word-to-pdf)

Turn a Word .docx into a PDF: preview the pages, then save them through your browser's print window. It runs in your browser, so the file is never uploaded.

PROMPT SOCIAL MEDIA

### [A Week of Threads Posts From One Idea](https://nexin.si/library/threads-week-from-one-idea)

Turns one idea into seven Threads posts in seven shapes, each under 500 characters, so you post every day of the week without repeating yourself.

SKILL CLAUDE

### [AI Code Review](https://nexin.si/library/ai-code-review)

A skill for Claude that reviews a diff or pull request like a senior engineer: real bugs first, each with the line, why it breaks and a fix.

PROMPT PRODUCTIVITY

### [AI Prompt Generator](https://nexin.si/library/ai-prompt-generator)

Turns a rough request into a complete prompt for ChatGPT or Claude, with role, context, steps, format and checks, asking only questions that matter.

TOOL PRODUCTIVITY · FREE

### [AVIF to JPG Converter](https://nexin.si/library/avif-to-jpg)

Convert AVIF to JPG in your browser so images open in any app, email or form, several at once. Your files stay on your device and are never uploaded.

TOOL PRODUCTIVITY · FREE

### [AVIF to PNG Converter](https://nexin.si/library/avif-to-png)

Convert AVIF to PNG in your browser with transparency kept and lossless output, several files at once. Your images are never uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [Base64 Decode](https://nexin.si/library/base64-decode)

Decode Base64 to readable UTF-8 text as you paste, standard or URL-safe, spaces and line breaks included. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [Base64 Encode](https://nexin.si/library/base64-encode)

Encode text to Base64 as you type, UTF-8 safe, with a URL-safe option that uses - and _ without padding. It runs in your browser, so nothing is uploaded.

SKILL BUSINESS

### [Business Plan Writer](https://nexin.si/library/business-plan-writer)

A skill for Claude that interviews you, then writes a lean business plan: market, go-to-market, unit economics and a 12-month table from your own numbers.

TEMPLATE CLAUDE

### [CLAUDE.md Starter for Any Project](https://nexin.si/library/claude-md-starter)

A complete CLAUDE.md for any project: house rules, stack, unit testing rules, git and safety limits, and a finish line Claude checks before it says done.

TOOL PRODUCTIVITY · FREE

### [Case Converter](https://nexin.si/library/case-converter)

Change text to Title Case, Sentence case, UPPERCASE, lowercase, camelCase, snake_case and more as you type. It runs in your browser: nothing is uploaded.

PROMPT BUSINESS

### [Cold Email Writer](https://nexin.si/library/cold-email-writer)

Writes a short cold email and two follow-ups for one prospect, built on a real reason to write, one clear ask and no hype, with subject lines under 50.

TOOL PRODUCTIVITY · FREE

### [Compress Image](https://nexin.si/library/compress-image)

Compress images with a quality slider, max width and JPG or WebP output, several at once. It runs in your browser, so the files stay on your device.

TOOL PRODUCTIVITY · FREE

### [Compress Video](https://nexin.si/library/compress-video)

Compress a video to a smaller MP4, with a size level, max resolution and an option to drop audio. It runs in your browser; files stay on your device.

SKILL CLAUDE

### [Conventional Commits Writer](https://nexin.si/library/conventional-commits)

A skill for Claude that reads your staged changes and writes Conventional Commits messages: the right type and scope, a clear subject, a body that says why.

PROMPT BUSINESS

### [Cover Letter Generator](https://nexin.si/library/cover-letter-generator)

Writes a one-page cover letter tailored to one job posting from your real experience, with a company hook, matched proof and a short email version.

PROMPT BUSINESS

### [Elevator Pitch](https://nexin.si/library/elevator-pitch)

Writes your elevator pitch in 10, 30 and 60-second versions for investors, clients, networking or a job search, plus one line people remember.

GUIDE SEO · FREE

### [Find Blog Topics People Actually Search For](https://nexin.si/library/find-blog-topics-people-search)

A 30-minute routine to go from a niche to a list of ten blog topics with real search demand, grouped in one cluster, using free tools and one prompt.

SKILL PRODUCTIVITY

### [Flashcard Maker](https://nexin.si/library/flashcard-maker)

A skill for Claude that turns notes, chapters or PDFs into clear flashcards, one fact per card, with an Anki import file, a Quizlet list and a quick quiz.

TOOL PRODUCTIVITY · FREE

### [HEIC to JPG Converter](https://nexin.si/library/heic-to-jpg)

Convert HEIC to JPG from your iPhone, several photos at once, in Chrome, Edge, Firefox or Safari. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [HEIC to PNG Converter](https://nexin.si/library/heic-to-png)

Convert HEIC to PNG with no compression loss, several iPhone photos at once, in any modern browser. Your photos stay on your device and are never uploaded.

GUIDE CLAUDE · FREE

### [How to Install Claude Code](https://nexin.si/library/install-claude-code)

Install Claude Code on Mac, Windows or Linux in five minutes, sign in, check it works and run your first task in a real project, with fixes for common errors.

SKILL WRITING

### [Humanize AI Text](https://nexin.si/library/humanize-ai-text)

A skill for Claude that rewrites AI-sounding drafts into plain, specific, human prose: it strips the tells, keeps your facts and shows what changed.

TOOL PRODUCTIVITY · FREE

### [Image Converter](https://nexin.si/library/image-converter)

Image converter to JPG, PNG or WebP (AVIF when your browser supports it), several files at once. It runs in your browser; your files stay on your device.

PROMPT MARKETING

### [Image Prompt Generator](https://nexin.si/library/image-prompt-generator)

Writes detailed prompts for AI image models from a simple idea: subject, composition, light, lens, style and text rules, in three directions you can pick from.

TOOL PRODUCTIVITY · FREE

### [Image Resizer](https://nexin.si/library/image-resizer)

Resize images by width, height, percent or exact size, several at once, and save as JPG, PNG or WebP. It runs in your browser; nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [Image to PDF Converter](https://nexin.si/library/image-to-pdf)

Convert any image to PDF: JPG, PNG, WebP, HEIC or AVIF, one page each, sized to the image, A4 or US Letter. It runs in your browser, with no upload.

SKILL SOCIAL MEDIA

### [Instagram Carousel Writer](https://nexin.si/library/instagram-carousel-writer)

A skill for Claude that writes swipeable Instagram carousels of 3 to 10 slides, educational or sales, with a cover that earns the swipe and visual notes.

GUIDE CLAUDE · FREE

### [Install a Skill in Claude](https://nexin.si/library/install-a-skill-in-claude)

How to add a downloaded skill to Claude in under two minutes, check that it loaded, and ask for work that makes Claude use it.

TOOL PRODUCTIVITY · FREE

### [JPG to PDF Converter](https://nexin.si/library/jpg-to-pdf)

Convert JPG to PDF, one page per photo in your order, sized to the image, A4 or US Letter. It runs in your browser, so nothing is uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [JPG to PNG Converter](https://nexin.si/library/jpg-to-png)

Convert JPG to PNG in your browser with lossless output, several images at once, for editing, design tools and uploads. Nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [JPG to WebP Converter](https://nexin.si/library/jpg-to-webp)

Convert JPG to WebP in your browser for lighter photos and faster pages, several images at once. Your photos stay on your device, never uploaded.

TOOL PRODUCTIVITY · FREE

### [JSON Formatter](https://nexin.si/library/json-formatter)

Format, beautify and minify JSON, with 2 or 4 spaces or tabs and sort keys. It runs in your browser, so your text stays on your device, never uploaded.

TOOL PRODUCTIVITY · FREE

### [JSON Validator](https://nexin.si/library/json-validator)

Check JSON as you type and see the exact line and column of any error, with a jump to the spot. It runs in your browser, and nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [JWT Decoder](https://nexin.si/library/jwt-decoder)

Decode a JWT into its header and payload as JSON, with iat, nbf and exp as dates and an expiry check. It runs in your browser, so the token stays put.

TOOL PRODUCTIVITY · FREE

### [M4A to MP3 Converter](https://nexin.si/library/m4a-to-mp3)

Convert M4A to MP3 from iPhone Voice Memos or iTunes so it plays on any device, at 128, 192 or 320 kbps. It runs in your browser; nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [MKV to MP4 Converter](https://nexin.si/library/mkv-to-mp4)

Convert MKV to MP4 so OBS recordings and downloads play on phones, TVs and editors. It runs in your browser; the file is never uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [MOV to GIF Converter](https://nexin.si/library/mov-to-gif)

Convert MOV to GIF from an iPhone video or a Mac screen recording, up to 20 seconds, 8 to 15 fps. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [MOV to MP4 Converter](https://nexin.si/library/mov-to-mp4)

Convert MOV to MP4 from an iPhone or QuickTime, often with no quality loss. It runs in your browser, so the video is never uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [MP4 to GIF Converter](https://nexin.si/library/mp4-to-gif)

Convert MP4 to GIF in your browser: pick the start, up to 20 seconds, 8 to 15 fps and a width up to 800 px. The video is never uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [MP4 to MP3 Converter](https://nexin.si/library/mp4-to-mp3)

Convert MP4 to MP3 and keep only the sound of a video, at 128, 192 or 320 kbps. It runs in your browser, so the video is never uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [MP4 to WebM Converter](https://nexin.si/library/mp4-to-webm)

Convert MP4 to WebM for web pages and HTML5 video, re-encoded right in your browser. Your video is never uploaded or stored, and it spends no credits.

SKILL PRODUCTIVITY

### [Meeting Minutes](https://nexin.si/library/meeting-minutes)

A skill for Claude that turns a transcript or rough notes into meeting minutes: decisions, action items with owners, open questions and a Slack recap.

PROMPT PRODUCTIVITY

### [Out of Office Message](https://nexin.si/library/out-of-office-message)

Writes internal and external out of office messages in formal, friendly and short versions, plus a holiday reply, with clear dates and a backup contact.

TOOL PRODUCTIVITY · FREE

### [PDF to JPG Converter](https://nexin.si/library/pdf-to-jpg)

Convert PDF to JPG, every page as its own image at 72, 144 or 216 dpi, with Download all. It runs in your browser, so the PDF is never uploaded.

TOOL PRODUCTIVITY · FREE

### [PDF to PNG Converter](https://nexin.si/library/pdf-to-png)

Convert PDF to PNG, every page as a lossless image at 72, 144 or 216 dpi, ready for slides, docs and design tools. It runs in your browser, no upload.

TOOL PRODUCTIVITY · FREE

### [PNG to JPG Converter](https://nexin.si/library/png-to-jpg)

Convert PNG to JPG in your browser for lighter photos and screenshots, several at once. Transparent areas turn white. Nothing is ever uploaded.

TOOL PRODUCTIVITY · FREE

### [PNG to PDF Converter](https://nexin.si/library/png-to-pdf)

Convert PNG to PDF, one page per screenshot or graphic, sized to the image, A4 or US Letter, with an optional margin. It runs in your browser, no upload.

TOOL PRODUCTIVITY · FREE

### [PNG to WebP Converter](https://nexin.si/library/png-to-webp)

Convert PNG to WebP in your browser for smaller images with transparency kept, several at once, ready for your website. Nothing is ever uploaded.

PROMPT BUSINESS

### [Resignation Letter](https://nexin.si/library/resignation-letter)

Writes a resignation letter in a formal and a warm version, with your last day, an offer to help with the handover and a two-line email to send it.

SKILL BUSINESS

### [SOP Writer](https://nexin.si/library/sop-writer)

A skill for Claude that writes standard operating procedures from notes or a recording: numbered steps, expected results, checks and troubleshooting.

PROMPT BUSINESS

### [STAR Method Interview Answers](https://nexin.si/library/star-method-answers)

Turns your raw work stories into STAR method interview answers of 60 to 90 seconds, with honest results and the follow-up questions to expect.

TOOL PRODUCTIVITY · FREE

### [SVG to PNG Converter](https://nexin.si/library/svg-to-png)

Convert SVG to PNG in your browser at 1x, 2x or 4x size, with transparency kept and several files at once. Your SVG files are never uploaded.

PROMPT BUSINESS

### [SWOT Analysis](https://nexin.si/library/swot-analysis)

Builds a SWOT analysis for your business or product with internal and external factors kept apart, then TOWS strategies and three clear priorities.

SKILL PRODUCTIVITY

### [Summarizer](https://nexin.si/library/summarizer)

A skill for Claude that summarizes long text, PDFs, transcripts and threads at the length you pick, with exact numbers, located quotes and gaps flagged.

PROMPT BUSINESS

### [Thank You Email After Interview](https://nexin.si/library/thank-you-email-after-interview)

Writes a thank you email after an interview, under 150 words with one specific detail, plus a panel version and a polite follow-up for a week later.

TOOL PRODUCTIVITY · FREE

### [URL Decoder](https://nexin.si/library/url-decoder)

Decode percent-encoded URLs and query strings into readable text as you paste, with + read as a space. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [URL Encode](https://nexin.si/library/url-encode)

Percent-encode a query value or a whole URL as you type, with a Whole URL option that keeps the separators. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [UUID Generator](https://nexin.si/library/uuid-generator)

Generate random version 4 UUIDs, from 1 to 500 at a time, lowercase or uppercase, with your browser's secure random generator. Nothing is uploaded.

PROMPT MARKETING

### [Unique Selling Proposition](https://nexin.si/library/unique-selling-proposition)

Writes five unique selling proposition options from different angles, each with a headline version, and picks the strongest one backed by your proof.

TOOL PRODUCTIVITY · FREE

### [Unix Timestamp Converter](https://nexin.si/library/unix-timestamp-converter)

Convert a Unix timestamp to a date, or a date to epoch time, in seconds and milliseconds, UTC and your own time zone. It runs in your browser.

SKILL BUSINESS

### [User Story Writer](https://nexin.si/library/user-story-writer)

A skill for Claude that turns a feature idea or PRD into INVEST user stories with Given/When/Then acceptance criteria, edge cases and a priority order.

TOOL PRODUCTIVITY · FREE

### [Video Converter](https://nexin.si/library/video-converter)

Video converter to MP4, WebM, MOV or MKV, or audio as M4A. It runs in your browser, so your files stay on your device. No upload, nothing stored.

TOOL PRODUCTIVITY · FREE

### [Video to GIF Maker](https://nexin.si/library/video-to-gif)

Turn a video into a GIF up to 20 seconds long, with your start point, frame rate and width. It runs in your browser, so the video is never uploaded.

TOOL PRODUCTIVITY · FREE

### [Video to MP3 Converter](https://nexin.si/library/video-to-mp3)

Convert a video to MP3 from MP4, MOV, WebM or MKV and keep only the audio, at up to 320 kbps. It runs in your browser, so nothing is uploaded.

TOOL PRODUCTIVITY · FREE

### [WAV to MP3 Converter](https://nexin.si/library/wav-to-mp3)

Convert WAV to MP3 and shrink big recordings from recorders or a DAW, at 128, 192 or 320 kbps. It runs in your browser; nothing is uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [WebM to MP4 Converter](https://nexin.si/library/webm-to-mp4)

Convert WebM to MP4 so screen recordings and browser clips open in any app or editor. It runs in your browser; the video is never uploaded or stored.

TOOL PRODUCTIVITY · FREE

### [WebP to JPG Converter](https://nexin.si/library/webp-to-jpg)

Convert WebP to JPG in your browser, several images at once, ready for forms, email and older apps. Your files stay on your device, never uploaded.

TOOL PRODUCTIVITY · FREE

### [WebP to PNG Converter](https://nexin.si/library/webp-to-png)

Convert WebP to PNG in your browser, several files at once, with transparency kept and lossless output. Your images are never uploaded anywhere.

TOOL PRODUCTIVITY · FREE

### [YAML Formatter (YML Formatter)](https://nexin.si/library/yaml-formatter)

Format and beautify YAML and .yml files, with comments kept, 2 or 4 spaces and sort keys. It runs in your browser, so your text stays private.

TOOL PRODUCTIVITY · FREE

### [YAML Validator (YAML Lint)](https://nexin.si/library/yaml-validator)

Check YAML and .yml files as you type, with errors by line and column and a jump to the spot. A YAML lint that runs in your browser, nothing uploaded.

TOOL PRODUCTIVITY · FREE

### [YAML to JSON Converter](https://nexin.si/library/yaml-to-json)

Convert YAML or .yml to JSON, or JSON back to YAML, as you type, with errors by line and column. It runs in your browser, so nothing is uploaded.

PROMPT SOCIAL MEDIA

### [YouTube Title Generator](https://nexin.si/library/youtube-title-generator)

Writes 10 YouTube title options for one video in five proven shapes, each under 60 characters, plus thumbnail text that adds to the title.