Kristian Mario Mišković · @TekiDeki · Vršac, Serbia
Old man but… coder. I build single-file web apps that solve exactly one problem well - pure HTML, CSS and JavaScript. No backend, no account, no analytics. Most tools keep data in your browser; the speech reader may send text to an online voice provider, depending on the voice.
1<!doctype html>
2<html lang="en">
3 <head>
4 <title>Which is cheaper?</title>
5 <style>/* the whole CSS */</style>
6 </head>
7 <body>
8 <!-- no build step -->
9 <!-- no backend -->
10 <!-- no trackers -->
11 <script>/* the whole JS */</script>
12 </body>
13</html>The toolbox
Every tool is free. Most are installable; Unit Atlas also downloads as a standalone HTML file. Offline support keeps them useful without a connection. Search in any of the four languages - the index knows them all.
A world of measures. Made simple.
11 international categories plus Romanian and Serbian land measures. Instant conversions, saved references and shareable links, in one downloadable HTML file.
Never lose the grocery-aisle math again.
Type in two products - price and size - and get an instant price-per-unit verdict: “B is 12% cheaper.”
Your finances, without handing over your data.
Track income and expenses, categorise spending and watch interactive charts update in real time. Everything lives in your browser.
Monthly payment, total interest and a full repayment plan.
Enter a loan and see the monthly payment, total interest, payoff date and a full schedule. Test extra payments, export CSV. Everything stays in your browser.
Breadboard simulator with LEDs, sensors and transistors.
Build circuits on a breadboard and press Simulate. Learn with 10 lessons, 60 quiz cards and 12 broken circuits to repair. Everything runs in your browser.
The Luminance Master - prompts that actually work.
Stop guessing which words work. Pick from curated dropdowns - lighting, composition, camera, film stock, atmosphere - and the tool assembles a coherent, engine-specific prompt.
Your BMI in two taps - in four languages.
Weight plus height, and you get an instant BMI with a clear category. Dark and light theme, shareable language links, works offline.
Any page, on any device, in seconds.
Load a local HTML file or paste a URL and it renders inside real device frames. For developers, designers and anyone who ships for small screens.
A private bet journal - not betting advice.
Record and settle bets, review net profit and settled-bet ROI, and export JSON backups. No account, no tracking - the data stays in your browser.
Find a word. Start an idea.
Generate random words in four languages for writing, language practice or creative prompts. Filter by length, copy a word, revisit recent history - all locally.
Placeholder text, exactly how you need it.
Generate paragraphs, sentences or an exact word count. Copy the text or download a plain TXT file - no accounts, no tracking, no backend.
Random by design. Private by default.
Passwords generated locally with Web Crypto. Choose length and character sets, reveal only when needed, copy or export TXT after a plaintext warning.
Point, scan, know. Nothing is uploaded.
Scan QR codes and barcodes with the camera or from an image, and read product details for EAN/UPC codes straight from Open Food Facts. Content is understood, not just printed.
Every page as a JPG or PNG, made in the tab.
Drop a PDF and take every page back as a JPG or PNG at 72, 150 or 300 dpi, or only the pages you list. The pages are drawn by the browser itself, so nothing is uploaded, no account is asked for, and the whole set comes down as one ZIP.
Subtitles that open cleanly, fixed in the tab.
Drop an SRT or VTT, move the timing, repair the cues that overlap, re-wrap the long lines and take the file back in either format. The page reads the file itself: nothing is uploaded, no account is asked for, and a file saved in the old Windows encoding still opens.
A CV that prints, without the paywall.
Fill the form, watch the page, print it as a real PDF. Classic, two columns or a banner across the top, on A4 or Letter, in text a hiring robot can read. No account, no watermark, and the download is the print dialog.
Bars that print clean. Nothing leaves the tab.
EAN-13, EAN-8, UPC-A, ITF-14, Code 128 and Code 39, drawn as you type, with the check digit worked out for you. Vector SVG for a print shop, PNG at 300 dpi, or a whole A4 sheet of labels.
Smaller photos. Without the metadata.
Batch compress and resize images right in the browser, and get them back with EXIF, GPS, camera and timestamp data removed. Download single files or the whole batch as one ZIP.
Listen to your text with the voices available in your browser.
Paste text or load a .txt file, listen by chapter and adjust reading speed. No audio download. Local voices keep text on-device; online voices may send it to their provider.
Every colour, measured. Nothing uploaded.
Pull a palette from a photo with k-means, build harmonies and gradients, check WCAG 2.x contrast with an accessible suggestion, and see the result through seven colour blindness simulations.
Your cycle, on your device.
Log flow, symptoms, mood, notes and basal temperature. The calendar groups your periods, predicts the next ones from your own averages and shades the fertile window. Nothing leaves the browser.
Passport photos, printed at home.
Crop a photo to 35 x 45 mm, 30 x 40 mm or 51 x 51 mm against millimetre guides, then print a full 10 x 15 sheet at 300 dpi with cut marks. The photo never leaves the browser.
Cut a video without uploading it.
Pick the start and the end on a timeline, drop the sound if you want, and save a smaller file. The clip is processed on your device - no upload, no account, no server.
The hour that works for every city in the room.
Add the cities and see which hours fall inside working hours for all of them. Offsets come from the browser, so daylight saving is never stale. The cities and the day travel in the link, and nothing is uploaded.
Merge, split and rotate PDFs without uploading them.
Drop several PDFs or images, put the pages in the order you want, turn the ones that came out sideways, and download one clean file. You can also pull a page range out of the document. Everything happens in the tab: no server, no account.
A code that never expires, because no server is behind it.
Turn a link, a text, a WiFi network, a contact card, an email, a phone number or an SMS into a code drawn by your own browser. Take SVG for print or PNG up to 2048 px, or paste a list of addresses and print a whole A4 sheet with captions. Nothing is uploaded, so nothing can switch the code off later.
Put your signature on a PDF without uploading it.
Open a PDF, draw, type or photograph a signature, and drop it on the page. Drag it into place, pull a corner to resize it, add today's date, and download the file with the signature drawn into the page. The document never leaves the tab.
Twelve questions a day, each one with its source.
A round of twelve short questions, four answers and one correct, from arithmetic and logic to geography, science, words, history and culture. After every answer come the explanation, the source and the date the bank was checked. The daily round is dealt from the date itself, so everybody gets the same twelve, and the score link carries the challenge on. No account, no upload, no statistics.
Is your connection solid, or just fast?
Continuous latency probes measure jitter, lost probes and outages over minutes or hours, then hand you a verdict with the thresholds shown. The report and the full data export stay in your browser.
Clean CSV files without sending them anywhere.
Edit, filter, clean and export CSV or TSV files locally. Detect delimiters, trim whitespace, remove duplicates and keep every value as text.
Check any file without sending it anywhere.
Calculate MD5 and SHA-256 locally, compare an expected checksum and export a manifest. Multi-file drag and drop, one read and no upload.
Favicons and app icons, without uploading your image.
Crop a picture or type a monogram, check the real 16, 32 and 48 pixel results, then download a complete icon pack: ICO, six PNG icons, a web manifest and the HTML snippet. All of it on your device.
Small games, one file each, no account.
Word and logic games that run entirely in the browser. The first one is a hangman on themes: a hidden word, six lives, a letter hint and your own streak. Words are checked against the alphabet of their own language, including Serbian Cyrillic. No account, no ads, no upload.
Nothing matches that. Try another word, or press Esc to clear the search.
How I build
Constraints are the whole point. They keep the tools fast, cheap to host and honest about your data.
01
One index.html holds the whole app - markup, CSS and JavaScript together. Nothing to build, nothing to bundle.
02
Most tools keep data in your browser. Features that use external providers may send the relevant data to them; each app card explains when.
03
The tools ship a service worker and a web app manifest: open one once, and it works on a plane, in a basement, on a farm. Games is the exception - its own security policy blocks service workers, so it needs a connection.
04
Big touch targets, responsive layout, light and dark themes, no horizontal scrolling on a small phone.
05
A library only when it clearly improves quality - kept light, bundled locally where practical, licence respected.
06
Static files on a free tier - GitHub Pages for the tools, Cloudflare's edge network for this site. No servers, no bills.
“The best code is the code you don't have to ship.” - @TekiDeki
Shortcuts
Short addresses for every tool. Each one redirects to the live app on GitHub Pages, Unit Atlas included. Use the copy button to share an address.
Unit Atlas now lives in its own repository and is served from tekideki.github.io/Unit-Converter. All shortcuts use 302 redirects: most go to GitHub Pages, the games to games.freehtml.dev, where each app manages its own offline support.
About
I'm Kristian Mario Mišković, @TekiDeki, writing code from Vršac, Serbia. I've been around long enough to remember when a website was a folder of files - and I still think that's a perfectly good way to build one.
These tools started as answers to small annoyances: which jar of coffee is actually cheaper, what BMI category am I in, how do I strip GPS data from 40 photos before posting them. None of them needed a server, so none of them got one.
If one of them saves you three seconds in a grocery aisle, a star on GitHub costs nothing - and a bug report costs even less.