Guides & Tutorials

What is a URL shortener?

A URL shortener is a service that takes a long web address — sometimes hundreds of characters — and maps it to a short, memorable alternative. When someone visits the short link, they are instantly redirected to the original destination.

Short links have become essential in digital marketing and content sharing for several reasons:

• Character-limited platforms: Platforms like Twitter/X impose strict character counts. A raw URL can consume most of an update before you have said anything meaningful.
• Print media: Long URLs are impossible to type from a poster, flyer, or business card. A short alias like short.net-tools.ch/event is easy to remember and type.
• Analytics: Unlike a raw URL, a shortened link can record every click along with the timestamp, geographic location, device type, and referrer — invaluable data for campaign measurement.
• Aesthetics: Clean links look more professional in emails, presentations, and newsletters.

How the net-tools Link Shortener works

When you submit a URL, the service stores the full destination URL in a database and creates a short token — either a randomly generated alphanumeric string or your custom alias. When a visitor accesses the short link, the server looks up the token, increments the click counter, and sends a 301 or 302 HTTP redirect to the original URL. The entire process takes milliseconds.

Optional features extend this behaviour:

• Custom aliases: You can choose a meaningful word or phrase instead of a random string, e.g. short.net-tools.ch/summer-sale.
• Password protection: Visitors must enter a password before they are redirected. Useful for sharing links with a specific audience.
• Expiry dates: The link automatically stops working after a date you choose. Essential for time-limited promotions, event registrations, or temporary access to documents.

Step-by-step: shorten a URL

1. Navigate to short.net-tools.ch.
2. Paste your long URL into the input field at the top of the page.
3. (Optional) Click "Advanced options" to set a custom alias, expiry date, or password.
4. Press Shorten. The short link appears immediately below.
5. Click the copy icon to copy the link to your clipboard, or use the QR icon to open it in the QR Code Generator.
6. Share the link wherever you need it.

Step-by-step: view click analytics

1. After shortening, note the management link shown on the confirmation screen (or bookmark the stats URL).
2. Visit the stats URL at any time to see total clicks, unique clicks, a timeline graph, top countries, and top referrers.
3. Use these metrics to evaluate which channels are driving traffic and optimise future campaigns accordingly.

Common use cases

• Email newsletters: Replace every tracking URL with a short, clean link for a professional appearance.
• Social media campaigns: Share a single short link across platforms and compare click-through rates by channel using the analytics dashboard.
• QR codes on print: Shorten the URL first, then paste it into the QR Code Generator. The shorter the URL, the less complex (and more scannable) the QR code.
• Temporary access: Set an expiry date to automatically revoke access to a document or page after an event or deadline.

Why not just email the file?

Email attachments are capped at around 25 MB by most providers — a fraction of a single high-resolution video or a complex CAD file. Even when sending is possible, email stores files indefinitely on both sender and recipient servers, and the data may be scanned for advertising purposes by some providers.

Cloud storage services like Google Drive or Dropbox solve the size problem but introduce a new one: both the sender and recipient need accounts, and files remain stored — and potentially accessible to the provider — long after they are no longer needed.

net-tools Secure File Upload addresses all of these problems: files up to 10 GB, automatic deletion, no accounts, and end-to-end TLS encryption.

Technical details

• Transfer encryption: All data is transmitted over TLS 1.3, the current industry standard for in-transit encryption.
• Server location: Files are stored on servers physically located in Switzerland, governed by some of the strongest data protection laws in the world (nDSG / GDPR-equivalent).
• Automatic deletion: Files are permanently deleted from disk at the expiry time you choose (between 1 hour and 30 days). No manual intervention is required and there is no recovery after deletion.
• Unique download URLs: Each upload generates a cryptographically random URL. It is computationally infeasible to guess a valid link by brute force.

Step-by-step: upload and share a file

1. Go to upload.net-tools.ch.
2. Drag your file onto the drop zone, or click Browse files to select from your device. Any file format is accepted.
3. Set the expiry period using the slider or dropdown (e.g. "7 days").
4. Click Upload. A progress indicator shows the transfer in real time.
5. When the upload is complete, copy the generated download link.
6. Send the link to your recipient by email, chat, or any other channel.
7. The recipient opens the link and downloads the file — no login required on their end.

Best practices

• Choose the shortest expiry period that works for your workflow. Shorter windows reduce the window of opportunity if the link is forwarded unexpectedly.
• For highly sensitive documents, compress and password-protect the file before uploading. This adds an extra layer of protection independent of the upload service.
• If you are sharing with a colleague, consider using P2P Transfer instead — no file ever touches a server.

Why file compression matters

File size affects almost every part of the digital workflow. Smaller files mean faster email delivery, quicker web page loads, lower storage costs, and easier sharing over slow connections. But naive compression (such as simply lowering image quality to the minimum) produces ugly, unusable results.

net-tools' File Compressor uses smart, format-aware algorithms that find the best balance between size and visual fidelity automatically.

Supported formats and what happens to each

• JPEG: Redundant high-frequency pixel data is removed. The compressor selects the highest quality level at which the change is imperceptible to the human eye — typically achieving 40–70% size reduction.
• PNG: Alpha channel data and metadata are stripped, and lossless re-encoding is applied using an optimal compression level. Transparency is fully preserved.
• WebP: Re-encoded using Google's modern WebP format algorithms for additional savings. WebP files are typically 25–35% smaller than equivalent JPEG files at the same visual quality.
• PDF: Embedded images are recompressed, duplicate objects are merged, and unnecessary metadata is removed. For scanned PDFs, aggressive image compression is applied before re-embedding.
• ZIP / archives: The archive is re-packed using a higher-efficiency compression algorithm (zopfli or brotli where applicable).

Step-by-step: compress an image

1. Open compress.net-tools.ch.
2. Drag your image file onto the upload area or click to browse.
3. Adjust the quality slider if you want manual control, or leave it on "Auto" for the best automatic result.
4. Click Compress.
5. Review the before/after file size comparison shown on screen.
6. Click Download to save the compressed file.

Tips for best results

• For web images, aim for files under 200 KB for hero images and under 100 KB for thumbnails. This keeps page load times under the 3-second threshold that most users expect.
• If you have a PNG with no transparency, consider converting it to JPEG or WebP — you will almost always get a significantly smaller file.
• Compress PDFs before uploading them to document-sharing services to stay within attachment size limits and reduce storage costs.

What is a cryptographic hash?

A cryptographic hash function is a mathematical algorithm that takes an input of any size — a word, a sentence, or a 10 GB file — and produces a fixed-size output called a digest, hash, or checksum. Three fundamental properties make this useful for security:

• Deterministic: The same input always produces the same hash. If you hash the same file twice, you get the same result.
• Avalanche effect: Changing even a single bit in the input produces a completely different hash. This makes it trivially easy to detect any modification, however small.
• One-way: It is computationally infeasible to reconstruct the original input from the hash output.

Algorithm comparison

Step-by-step: verify a downloaded file

1. Download the file from the vendor's website. Also note the expected checksum published on the same page (usually labelled "SHA-256" or "MD5").
2. Open hashsum.net-tools.ch.
3. Select the File tab and choose the same algorithm as the published checksum.
4. Drag and drop your downloaded file onto the input area. The hash is calculated entirely in your browser using the Web Crypto API — your file is never uploaded.
5. Paste the expected hash from the vendor's page into the Compare field.
6. A green ✓ confirms the file is intact. A red ✗ means the file was modified or corrupted — do not use it.

Other uses

• Password storage research: Hashing a password demonstrates how one-way functions work — but remember, never store passwords as raw MD5 or SHA hashes in production. Use bcrypt, Argon2, or scrypt instead.
• Document fingerprinting: Hash a contract before and after sending it to prove it hasn't been altered. Store the hash in a separate location as evidence.
• Deduplication: Compare hashes of large files to find exact duplicates without opening each one.

How QR codes work

A QR (Quick Response) code is a two-dimensional barcode that encodes data as a pattern of black and white squares. A smartphone camera or dedicated QR reader decodes the pattern into text, a URL, a phone number, or other data types in under a second.

QR codes support several error-correction levels — L, M, Q, and H — which allow the code to remain readable even if 7%, 15%, 25%, or 30% of the image is damaged, respectively. Higher error-correction means a more complex (denser) pattern.

Supported data types

• URL: Opens a web page when scanned. Most common use case.
• Plain text: Displays a text message to the user.
• Email: Opens the user's email client with a pre-filled recipient, subject, and body.
• Phone number: Initiates a phone call.
• SMS: Opens the messaging app with a pre-filled number and message.
• vCard: Adds a contact to the user's address book with name, phone, email, and address.
• Wi-Fi: Joins a wireless network automatically — no typing the password. Encodes the SSID, password, and encryption type.

Step-by-step: generate a QR code for a URL

1. Open qr-gen.net-tools.ch.
2. Select URL as the data type.
3. Paste your URL. For best results, use a shortened URL (see the Link Shortener guide) to keep the QR code simple.
4. Choose the size (in pixels) appropriate for your use — 300×300 for digital use, 1000×1000 or larger for print.
5. Optionally customise foreground and background colours to match your brand. Ensure sufficient contrast for reliable scanning.
6. Select the error-correction level. Use "H" (30%) if you plan to add a logo over the centre of the code.
7. Click Generate and then Download as PNG (for web/digital) or SVG (for print — infinitely scalable).

Print guidelines

• Always test-scan the code before printing at scale. Scan it with multiple devices (iOS and Android) to confirm it works.
• Maintain a quiet zone — a margin of at least 4 modules (squares) around the code — for reliable scanning.
• Minimum recommended print size: 2 cm × 2 cm for standard scanning distance. Go larger for posters viewed from a distance.

What is OCR?

OCR stands for Optical Character Recognition. It is the process of analysing an image of text — whether a scanned document, a photograph, or a screenshot — and converting the visual representation of each character into machine-readable text that can be selected, searched, copied, and edited.

Without OCR, a scanned PDF is nothing more than a series of images. You cannot search for a word, copy a sentence, or have a screen reader interpret the content. OCR unlocks all of these capabilities.

How the engine works

net-tools OCR PDF uses a high-accuracy recognition engine trained on millions of documents in over 30 languages. The process for each page is:

1. Pre-processing: The image is deskewed (straightened), denoised, and contrast-enhanced to improve recognition accuracy.
2. Layout analysis: The engine identifies text blocks, headings, tables, and images within the page.
3. Character recognition: Each character is identified and assigned a confidence score.
4. Output generation: The recognised text is embedded invisibly behind the original image in the PDF, preserving the exact visual appearance while making every word selectable and searchable.

Step-by-step: OCR a scanned PDF

1. Open ocrpdf.net-tools.ch.
2. Upload your scanned PDF (up to 100 MB).
3. Select the document language from the dropdown. Selecting the correct language significantly improves accuracy.
4. Click Process. The tool processes each page — progress is shown in real time.
5. Download the output PDF. Open it in any PDF reader and use Ctrl+F (or Cmd+F) to confirm that text is now searchable.

Improving accuracy

• Scan at 300 DPI or higher. Lower-resolution scans produce noticeably worse OCR results.
• Ensure good lighting when photographing physical documents — avoid shadows across the text.
• For documents with multiple languages on the same page, choose the language that occupies the most space.

What is WebRTC peer-to-peer transfer?

WebRTC (Web Real-Time Communication) is a browser API that allows two browsers to establish a direct encrypted connection to each other without routing data through an intermediate server. Originally designed for video calls, it works equally well for sending arbitrary data — including files of any size.

The key privacy benefit is that your file never passes through any third-party server. It travels in an encrypted stream directly from your browser to the recipient's browser. Nobody — not even net-tools — can see or record the content.

How the connection is established

To set up a direct connection, both browsers need to know each other's network addresses. This initial handshake (called signalling) is briefly facilitated by a lightweight relay server. Once the connection is established, the relay server drops out and all subsequent data flows directly peer-to-peer. The relay never sees the file data — only the connection metadata.

Step-by-step: transfer a file

1. Open transfer.net-tools.ch on the sender device.
2. Click Send a file. A unique transfer code and QR code are displayed.
3. Open transfer.net-tools.ch on the receiver device (or in a second browser window).
4. Click Receive a file and enter the transfer code shown on the sender device, or scan the QR code.
5. Once both parties are connected, click Select file on the sender side and choose the file to send.
6. The transfer begins immediately. A progress bar shows speed and completion percentage on both devices.
7. The receiver is prompted to save the file when the transfer completes.

Limitations and considerations

• Both devices must remain online: Unlike an upload-based service, the sender's browser must stay open for the entire duration of the transfer.
• Speed depends on the network: On the same local Wi-Fi network, transfers can be very fast. Over the internet, speed depends on the available bandwidth of both parties.
• Corporate firewalls: Some strict corporate networks block WebRTC connections. In these cases, the transfer may fall back to routing through a TURN relay, slightly increasing latency.

What are JavaScript i18n files?

Internationalisation (i18n) is the process of building software so it can be adapted to different languages and regions without engineering changes. Most JavaScript frameworks — React, Vue, Angular, Next.js — manage translations through locale files: JSON or JavaScript objects that map a key to a translated string.

A typical locale file looks like this:

{
  "nav.home": "Home",
  "nav.about": "About us",
  "cta.button": "Get started",
  "error.required": "This field is required"
}

When launching a product in a new market, you need an identical file for each target language — with all the string values translated, but all the keys left exactly as they are. Doing this manually for hundreds of keys is tedious and error-prone.

How the JS Translator works

net-tools JS Translator reads your JSON locale file, extracts all string values while preserving the key structure, sends only the values to a translation engine, and reassembles the translated values back into an identical JSON file. The output is a valid, drop-in replacement for the original file in the new language.

Keys are never translated, interpolation tokens like {{name}} or {count} are preserved, and nested objects are handled transparently.

Step-by-step: translate a locale file

1. Open js-translator.net-tools.ch.
2. Upload your source locale JSON file (e.g. en.json).
3. Select the target language from the dropdown (e.g. German, French, Spanish, Japanese).
4. Click Translate. The tool processes all strings and shows a preview with both source and translated values side by side.
5. Review the output. You can manually edit any translation directly in the preview table.
6. Click Download to save the translated file (e.g. de.json) ready to drop into your project.

Tips for quality translations

• Use descriptive keys that give context — "checkout.button.confirm_order" is far more informative than "btn3" for the translation engine.
• Keep UI strings short and neutral in the source file. Avoid idioms that may not translate naturally.
• Always have a native speaker review machine-translated UI copy before shipping to production — especially for buttons, error messages, and legal text.
• For large projects with thousands of keys, split the locale file into logical sections and translate one section at a time for easier review.