Online tools that work offline
Every tool below runs entirely in your browser. Your files, passwords, IDs and pasted text are processed on your device and never uploaded — which is also why they keep working with no internet connection. Try any of them in airplane mode.
109 tools in four groups · how this works and how to verify it
Files: images & PDFs
The file you drop in is opened by your own browser. It is compressed, cropped, merged or redacted on your device and downloaded straight back — no server ever holds a copy.
- Add Border to Image White, black or polaroid photo frames.
- Add QR Code to PDF Stamp a scannable QR onto any PDF page.
- Add Text to Image Captions, memes and labels — drag into place.
- Add Text to PDF Type onto any page — or insert a note page.
- Blur / Pixelate Image Censor screenshots — blur or mosaic any area.
- Compress PDF Shrink PDF file size — free, private, no upload.
- Crypto Payment QR Generator Bitcoin & Ethereum payment QR codes with amount.
- EXIF Viewer & Remover See what your photo reveals — then strip it.
- HEIC to JPG Convert iPhone HEIC photos to JPG — free, private.
- Image Compressor Compress JPG, PNG & WebP online — free, no signup.
- Image Cropper Crop images online to any size.
- Image Format Converter Convert between JPG, PNG and WebP.
- Image Resizer Resize images by width, height or ratio.
- Image Splitter Cut one photo into a 3×3 Instagram grid.
- Image to Base64 Convert an image to a Base64 data URI.
- Image to PDF Convert JPG/PNG images to a PDF.
- Image Watermark Add a text watermark to images.
- Merge PDF Combine multiple PDFs into one.
- PDF Page Numbers Add page numbers to a PDF.
- PDF Redact True blackout — text removed, then verified.
- PDF Signature Draw, type, or upload — sign in the browser.
- PDF to JPG Convert PDF pages to images.
- PDF Watermark Stamp text across every PDF page.
- QR Code Generator Create QR codes for links, text, Wi-Fi & more.
- QR Code Scanner Read a QR code from an image.
- Rotate & Flip Image Rotate, mirror or straighten a photo.
- Rotate PDF Rotate PDF pages 90/180/270°.
- Round Image Corners Rounded corners or a perfect circle avatar.
- Split PDF Extract pages from a PDF.
- SVG to PNG Vector in, crisp pixels out — at any scale.
- Wi-Fi QR Code Generator Let guests scan to join your Wi-Fi.
Passwords, keys & encryption
Passwords, one-time codes, hashes and encrypted text are generated with the Web Crypto API built into your browser. Nothing is transmitted, so there is nothing to intercept or log.
- 2FA Code Generator TOTP authenticator codes — 100% local & private.
- Hash Generator SHA-1, SHA-256 and SHA-512 hashes.
- JWT Decoder Decode JWT header and payload.
- Password Generator Create strong, random passwords instantly.
- Password Strength Checker Estimate password strength & entropy.
- Text Encrypt / Decrypt Password-protect text with AES-256.
IDs, tax numbers & wallet addresses
Checksums for IBANs, national IDs, tax numbers and crypto addresses are pure arithmetic. The number you paste is validated on the page and never sent anywhere — which is exactly what you want for data this sensitive.
- Argentina CUIT / CUIL Validator Validate a CUIT/CUIL check digit.
- Australia ABN Validator Validate an Australian ABN.
- Barcode Validator (EAN-13 / UPC-A) Validate EAN-13 and UPC-A barcodes.
- Batch ID Validator Validate a whole list of tax IDs at once.
- Bitcoin Address Validator Check BTC address format & checksum.
- Chile RUT Validator Validate a Chilean RUT/RUN check digit.
- Colombia NIT Validator Validate a NIT & its dígito de verificación.
- CPF / CNPJ Validator Validate Brazilian CPF and CNPJ numbers.
- Credit Card Validator Check a card number with Luhn.
- Ethereum Address Validator Verify EIP-55 checksum & compare addresses.
- France SIREN / SIRET Validator Validate a French SIREN or SIRET.
- Germany Steuer-ID Validator Validate a German tax ID.
- IBAN Validator Check IBAN checksum and country length.
- India PAN Validator Validate an Indian PAN format.
- Indonesia NIK Validator Check & decode a 16-digit KTP NIK.
- ISBN Validator Check ISBN-10 and ISBN-13 check digits.
- ISIN Validator Validate a securities ISIN.
- Italy Codice Fiscale Validator Validate an Italian Codice Fiscale.
- Japan My Number Validator Validate a Japanese My Number.
- Mexico CURP Validator Validate a Mexican CURP & check digit.
- Mexico RFC Validator Validate a Mexican RFC structure.
- Poland PESEL Validator Validate a Polish PESEL check digit.
- Singapore NRIC / FIN Validator Validate a Singapore NRIC or FIN.
- South Africa ID Validator Validate a South African ID number.
- Spain DNI / NIE Validator Validate a Spanish DNI or NIE.
- Thailand National ID Validator Validate a Thai national ID number.
Text, code & data you paste
Formatters, converters and text utilities run as plain JavaScript on the page. Paste a private JSON payload, a draft, or a config file: it stays in your tab.
- ASCII / Unicode Lookup Characters to code points.
- Base64 Encode / Decode Encode and decode Base64 text instantly.
- Binary Translator Convert text to binary and back.
- Case Converter Change text to UPPER, lower, Title & more.
- Chmod Calculator Unix file permissions (octal ↔ rwx).
- CIDR Subnet Calculator IPv4 network, mask & host range.
- Citation Generator APA, MLA & Chicago citations.
- Cron Expression Parser Explain cron & see the next runs.
- CSS Minifier Compress CSS by removing whitespace.
- CSV to JSON Convert CSV data to JSON and back.
- Fancy Text Generator Cool Unicode fonts for social media.
- Find and Replace Text Replace text, with regex option.
- HTML Entity Encoder / Decoder Encode and decode HTML entities.
- HTML Minifier Shrink HTML by removing whitespace.
- HTTP Status Codes Look up any HTTP status code.
- JSON Diff Checker Compare two JSON objects by key.
- JSON Formatter Format, validate & minify JSON.
- Lorem Ipsum Generator Generate placeholder text fast.
- MAC Address Generator Random MAC addresses for testing.
- Markdown Preview Write Markdown, see it rendered live.
- Morse Code Translator Translate text to Morse and back.
- NATO Phonetic Alphabet Spell words with Alpha, Bravo, Charlie.
- Number Formatter Add thousands separators & decimals.
- PX to REM Converter Convert px ↔ rem for CSS.
- Query String Parser URL query string to JSON.
- Readability Score Checker Flesch reading ease & grade level.
- Regex Tester Test regular expressions live.
- Remove Accents Strip diacritics from text.
- Remove Duplicate Lines Delete repeated lines from text.
- Remove Extra Spaces Trim and collapse extra whitespace.
- Remove Line Breaks Strip or replace line breaks.
- Reverse Text Reverse characters, words or lines.
- ROT13 & Caesar Cipher Encode and decode shift ciphers.
- Slug Generator Turn text into clean URL slugs.
- SQL Formatter Format & beautify SQL queries.
- Syllable Counter Count syllables in English text.
- Text Diff Checker Compare two texts and see changes.
- Text Repeater Repeat text any number of times.
- Text Sorter Sort lines A-Z, Z-A or by length.
- Timestamp Converter Convert Unix timestamps to human dates.
- URL Encoder / Decoder Percent-encode and decode URLs.
- User Agent Parser Detect browser, OS and device.
- UTM Link Builder Build trackable campaign URLs.
- UUID Generator Generate random UUID v4 identifiers.
- Word Counter Count words, characters, sentences & reading time.
- Word Frequency Counter Count how often each word appears.
Everything else runs locally too
Calculators, unit and currency converters, timers and generators are listed above only when they handle something sensitive — but all 240+ tools on this site follow the same rule: the work happens on your device. Browse the full collection →
Verify it yourself in 20 seconds
- Open a tool — the Image Compressor is a good first test.
- Switch on airplane mode or unplug your network.
- Run the tool. It still works, because nothing needs to reach a server.
Prefer hard evidence? Open your browser's DevTools Network tab while you work: no request carries your file. The why-local page explains the architecture in detail.
FAQ
Do these tools really work without an internet connection?
Yes. A tool page needs a connection to load the first time; after that, all processing happens on your device, so it keeps working if you go offline. Momo Tools is also installable as an app and caches the tools you have opened, so they are ready even before you are back online.
Are my files or inputs uploaded anywhere?
No. Files, passwords, IDs and pasted text are processed inside your browser using the Canvas, WebAssembly and Web Crypto APIs and are never sent to a server. The site only fetches static assets such as pages, fonts and translation dictionaries.
Why do most online tools upload your files?
Because processing on a server is the traditional way to build a web tool, and because a server that sees your files can also enforce size limits, add watermarks and collect data. Modern browsers are powerful enough to do the same work locally, which removes the need for an upload in the first place.
Is working offline the same as being private?
Offline capability is the simplest proof of privacy: if a tool finishes its job with your network switched off, it cannot have uploaded anything. That is why we suggest testing any tool, ours included, in airplane mode.
Is there a file size limit?
Only the memory of your own device. There are no server-side caps, no paid tiers to unlock larger files and no watermarks on the output.