Selim Ataballyev
Full-stack developer
Selim Ataballyev is a full-stack web developer who has shipped production web applications since 2020, owning the stack from architecture to deploy. He builds and maintains ZeroUtil: every tool in the catalog, the pages that explain them, and the articles on the blog. He reviews each tool page and article before it goes live and fixes what readers report through the contact page. His client work and portfolio are at selim.services.
How we work
Every tool page and article on ZeroUtil goes through the same four steps before it is published. There is no syndicated content, no rewritten competitor copy, and no page that ships without someone having used the tool it documents.
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We build the tool first, then write about it
The explanation is written against a working implementation, not the other way round. That is why the pages describe edge cases most tool sites skip - what happens to a hyphenated word in a word count, why a QR code with high error correction gets physically denser, where a percentage calculation stops being commutative. Those details come out of building the thing.
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Claims are checked against primary sources
Where a page states a standard, a limit, or an algorithm, it cites the specification or the vendor documentation rather than a secondary blog post. Those citations are stored with the page and rendered on it, so you can check the source without leaving the article. RFCs, W3C and WCAG documents, IRS and other regulator publications, and platform docs are the sources we treat as authoritative.
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Numbers are recomputed, not copied
Tax brackets, character limits, contrast ratios and similar figures are re-derived from the current source at review time. When a figure is year-bound we say which year it applies to on the page, because a silently stale number is worse than no number.
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Pages are re-reviewed on a schedule
Published pages carry a review date and are revisited rather than left to rot. When a standard changes, a platform limit moves, or a browser API we depend on ships or breaks, the affected pages are updated and the review date moves with the change.
The full rules we hold ourselves to are written down: our methodology covers how tools are built and tested, our editorial guidelines covers sourcing, corrections, and the line between explanation and promotion.
What we do and do not cover
We write about the things we build: text and data formats, encoding and hashing, browser APIs, PDFs and images, colour and accessibility, everyday finance and date maths. We do not publish medical, legal, or individual financial advice, and calculators that touch those areas say plainly what they can and cannot tell you. Where a tool is a rough guide rather than an authority - a sleep-cycle estimate, a tax-bracket figure - the page says so.
Corrections
If a page is wrong, we would rather hear it than not. Corrections are made on the page itself with the review date updated, not quietly removed. Reach us via the contact page .
Articles by Selim Ataballyev
Every Way to Hear FACEIT Demo Voice Comms, Compared
Console commands, a web calculator, CS Demo Manager, a voice extractor and extensions: what each does for FACEIT demo voice and what it leaves to you.
CS2 Demo Ticks: Tick to Time, and demo_gototick
A demo tick over the demo's tick rate is a timestamp. What catches people is which tick rate, which counter the number came from, and where demo_gototick lands.
What Importing a CS2 Crosshair Code Actually Changes
A CS2 crosshair share code writes 21 cl_crosshair variables, truncates a few, and skips your scoped crosshair. Why an imported one can still look off.
SteamID64, STEAM_0 and SteamID3 Share One Account Number
STEAM_0:Y:Z, SteamID3 and SteamID64 all read one 32-bit account number. How Valve's 64-bit layout works, and what it cannot derive: a vanity URL.
Converting Mouse Sensitivity Between Games Is One Division
Every cross-game sensitivity converter runs on one division and seven numbers. Where they come from, and four places the math stops matching how aim feels.
CS2 Crosshair Share Codes: What Those 25 Characters Hold
Twenty-five characters hold eighteen bytes, twenty-one console commands, and forty-one bits that carry nothing at all. Every field, decoded and measured.
How to Hear the Enemy Team's Voice in a CS2 Demo
Whether you can hear the enemy in a CS2 demo depends on what the server recorded, not on your console. Which demos carry it, and the mask for one side.
Why tsconfig.json Allows Comments and package.json Does Not
Both files end in .json. One accepts comments and trailing commas, the other throws. The difference is not the extension - it is which parser reads the file.
How to Compare a Design to Your Build, Pixel by Pixel
Overlay the mockup on the live page and let difference blending find the drift. The method, what each blend mode is for, and what the tools here cost.
The PDF Tools Everyone Should Know
A hands-on walkthrough of the PDF tasks you hit every week: compress, merge, split, convert, OCR, and sign, with steps you can follow right now.
Why You Can't Hear Voice in Your CS2 Demo (Fixes)
Can't hear voice comms in a CS2 or FACEIT demo? The real causes - no voice in MM/Premier demos, unset tv_listen_voice_indices, reset commands - and fixes.
How to Hear Voice Comms in a CS2 Demo
Hear voice comms in a CS2 demo with tv_listen_voice_indices: which demos record voice, how the slot bitmask works, and how to isolate one player or a side.
How to Hear Voice Comms in a FACEIT Demo (CS2)
FACEIT records both teams' voice, but only in one of the two demos a match leaves you. Which file to open, the three FACEIT commands, and the slot bitmask.
Password Strength: What Length and Character Sets Buy You
Entropy done honestly, NIST's current 15-character floor, and measured GPU cracking speeds showing the hash function matters more than the extra characters.
Base64 Explained: What It Is, Why It Exists, and When Not to Use It
What Base64 does to your bytes, the three variants that produce most decode failures, and the places it still earns its keep.
Client-Side Image Compression: What Happens in the Browser
The real pipeline behind Canvas, OffscreenCanvas and WebCodecs, which formats a browser will and will not encode, and when you still need a server.
JSON vs JSON5 vs JSONC: What Each Parser Actually Accepts
JSON, JSON5 and JSONC share a file extension but not a definition of valid. Tested against real parsers, including one library that disagrees with itself.
Percentage Points vs Percent: 5 Mistakes That Change the Answer
A rate that falls 1% and one that falls 1 percentage point are ten times apart. That confusion, plus four more that quietly turn a correct number wrong.
Tools maintained by Selim Ataballyev
AES-256 Encrypt / Decrypt Online - Free, In-Browser
Encrypt and decrypt text with AES-128, AES-192, or AES-256 in GCM, CBC, or CTR mode. PBKDF2 key derivation, entirely in your browser.
Fun & UtilityAesthetic Text Generator
Transform text into vaporwave, upside down, small caps, bold, italic, strikethrough, bubble, and square Unicode styles.
Math & CalculatorsAge Calculator
Calculate exact age in years, months and days from a birthdate.
Fun & UtilityASCII Art Generator
Convert text to large block-letter ASCII art. Supports A-Z, 0-9, and basic punctuation.
Video & AudioAudio Waveform Generator
Generate a SoundCloud-style waveform image from any audio file. Decoded in your browser, exported as PNG or SVG.
QR & BarcodeBarcode Reader
Free online barcode reader — upload an image to scan and decode barcodes. Supports EAN, UPC, Code 128, QR and more.
Developer ToolsBase64 Encoder & Decoder
Encode UTF-8 text to Base64 online or decode Base64 back to UTF-8 and plain text. Runs in your browser with no upload.
Image ToolsBase64 to Image Converter
Decode a Base64 string or data URL back into a viewable image and download it as PNG, JPG, WebP or GIF. Runs in your browser.
Security & PrivacyBasic Auth Header Generator
Create HTTP Basic Authentication headers from a username and password or API token.
QR & BarcodeBulk QR Code Generator
Generate multiple QR codes at once from a list of URLs or text.
Date & TimeBusiness Days Calculator
Count business days between two dates excluding weekends and custom holidays.
CSS & DesignColor Picker
Pick colors visually and get HEX, RGB, and HSL values.
Gaming ToolsCS2 Crosshair Code Decoder
Decode a CSGO-xxxxx crosshair share code into cl_crosshair console commands.
Gaming ToolsCS2 Demo Tick Calculator
Convert a CS2 demo tick to a timestamp and back, and copy the demo_gototick command that jumps there.
Gaming ToolsCS2 Demo Voice Extractor
Download each player's voice from a CS2 or FACEIT demo as a separate audio file, and see who talked when, round by round.
Gaming ToolsCS2 Sensitivity Converter
Convert mouse sensitivity between CS2, Valorant, Apex and more, with eDPI and cm/360.
Gaming ToolsCS2 Voice Comms Calculator
Hear specific players in a CS2 or FACEIT demo - upload it to auto-fill players and get the tv_listen_voice_indices commands.
CSS & DesignCSS Clip Path Generator
Create CSS clip-path shapes with visual editing and presets. Clip-path maker and CSS shape generator in one tool.
Date & TimeDate Difference Calculator
Calculate the exact difference between two dates in years, months, days, weeks, hours and minutes.
ConvertersEnergy Converter
Convert between joules, megajoules, calories, kilocalories, BTU, therms, watt-hours, kilowatt-hours and electronvolts.
Text ToolsFancy Text Generator
Generate stylish text with bubbles, squares, upside down and more for social media.
ProductivityFlashcard Maker
Create and study flashcards with front/back content, shuffle, and navigation.
Fun & UtilityFortune Cookie
Open a virtual fortune cookie to reveal a random fortune with lucky numbers. 50+ unique fortunes.
ConvertersFuel Economy Converter
Convert between MPG (US), MPG (UK), L/100km and km/L with inverse relationship handling.
Image ToolsGIF Maker
Turn multiple images into an animated GIF with custom frame delay.
Image ToolsImage Metadata Viewer
View file info, dimensions, aspect ratio, and basic EXIF data from any image.
Image ToolsImage Vectorizer
Convert PNG, JPG, WebP, GIF or BMP images to scalable SVG vector format directly in your browser.
Developer ToolsJSON Dialect Detector
Tell whether a file is JSON, JSONC or JSON5 - and convert it to strict JSON.
Text ToolsMarkdown to HTML
Convert Markdown to HTML with live preview.
Text ToolsMorse Code Translator
Translate text to Morse code and Morse code to text.
Home & LifestyleMoving Box Calculator
Estimate moving boxes needed by room type with breakdown by small, medium and large sizes.
ProductivityNotes Scratchpad
Simple persistent notepad with auto-save, word count, and local storage.
Security & PrivacyPBKDF2 Hash Generator
Derive cryptographic keys from passwords using PBKDF2 with configurable iterations, salt and hash function.
PDF ToolsPDF Compressor
Compress PDFs with Ghostscript image downsampling. Pick a quality preset. Files auto-deleted after 15 minutes.
Math & CalculatorsPercentage Calculator
Calculate percentages: X% of Y, percentage increase/decrease, and more.
ConvertersPressure Converter
Convert between pascals, kilopascals, bar, atmospheres, PSI, mmHg and torr.
Math & CalculatorsPrime Number Checker
Check if a number is prime and find all primes up to any limit.
QR & BarcodeQR Code Generator
Generate QR codes for URLs, text, email, phone and WiFi.
QR & BarcodeQR Code Reader
Scan and decode QR codes from any image online - upload a photo, screenshot or saved picture and read the QR contents instantly in your browser.
Fun & UtilityRandom Color Generator
Generate random colors with HEX, RGB and HSL values. Random color picker, colour randomizer and 5-color palette builder with history.
Fun & UtilityRandom Quote Generator
Generate random inspirational, funny, motivational, and wisdom quotes from a curated collection of 50+ quotes.
Text ToolsRandom String Generator
Generate random strings with configurable length and character set.
SEO & Web ToolsReadability Checker
Free reading level checker and writing grade level analyzer. Flesch-Kincaid, Flesch Reading Ease, Gunning Fog and Coleman-Liau scores in one place.
Text ToolsRemove Duplicate Lines
Remove duplicate lines from text with case-sensitive and sorting options.
Math & CalculatorsSalary / Hourly Rate Calculator
Convert between annual salary, monthly, weekly, daily and hourly pay rates.
Gaming ToolsSteamID Converter
Convert between SteamID64, STEAM_0:Y:Z, SteamID3 [U:1:W], account ID and profile URL.
Video & AudioVideo Cropper
Crop MP4, WebM, MOV and MKV videos to a rectangle or aspect preset (16:9, 9:16, 1:1, 4:3). Server-side FFmpeg, no signup. Files auto-deleted after 15 minutes.
Video & AudioVideo Reverser
Reverse an MP4, WebM, MOV or MKV video and its audio with one click. Server-side FFmpeg handles the full re-encode. Files auto-deleted after 15 minutes.
Video & AudioVideo Trimmer
Cut a section from MP4, WebM or MOV videos. Stream-copy is fast and lossless.
Video & AudioVoice Recorder
Record voice memos directly in your browser. The audio never leaves your device - no upload, no signup.
Text ToolsWord Counter
Count words, characters, sentences, paragraphs and estimate reading time.
Date & TimeWorld Clock
Live-updating clocks for multiple timezones. Add and remove cities to build your custom dashboard.