Why create a custom QR code
A QR code saves people from copying an address or contact details from printed material. The phone reads the encoded content and suggests the corresponding action: opening a page, joining a Wi-Fi network or adding a contact, depending on the apps available.
The CaptainDNS QR code generator renders the file on its servers from your input. You can keep the design black on white or adapt it to your material. Static downloads are free, with no sign-up required.
The main choice before printing concerns web addresses. A URL written directly into the QR code stays the same on every copy. If your campaign page needs to change, linking to a redirect gives you an intermediate address whose destination you control.
How to use the QR code generator in 3 steps
Step 1: Enter the content
Choose the QR code type, then fill in the fields shown. For a web address, enter the full URL, such as https://captaindns.com/en/pricing. For Wi-Fi, enter the network name, security mode and password if it uses one.
If you want to change the web destination later, sign in and select an active redirect from your account. The QR code will contain that host's HTTPS address at its root. A redirect still awaiting activation cannot be linked.
Review the content before working on the design. An incorrect digit in a phone number or a typo in the network name will end up in the QR code.
Step 2: Customize and generate the QR code
Open the appearance settings to choose colors, dot shapes and corner markers. You can add a gradient, make the background transparent, upload a logo or display a frame with the text 'Scan me'.
Set the size, quiet zone and error correction. Level M is the default; adding a logo requires H. Then start generation: our servers check the settings and render the QR code.
If the contrast is rejected, darken the dot and corner colors or lighten the background. After changing the form or style, regenerate the QR code so the download matches the new settings.
Step 3: Download and test
Download the result as PNG, SVG or PDF. Open it in the software you will use to prepare your poster or document, and keep the margin around the design.
Test an actual-size proof on several phones. Also check the resulting action: the right page opens, the expected network is offered or the contact details are correct. A sharp preview on screen does not replace this paper test.
Supported content
The form offers ten content types. Your choice determines the information to enter and the action the phone can suggest after scanning.
| Type | Content to enter | Use |
|---|---|---|
| URL | Web address or active redirect from your account | Open a page |
| Text | Free text | Display an instruction or information |
| Wi-Fi | Network name, security, password and hidden network setting if needed | Offer to connect to the network |
| vCard contact | Name and contact details, including business fields and address | Offer to add a contact |
| SMS | Phone number and optional message | Prepare a text message |
| Phone | Number to call | Offer to make a call |
| Address, optional subject and body | Prepare an email | |
| Geographic location | Latitude and longitude | Pass coordinates to a map app |
| Calendar | Title, start, end, location and description | Offer to add an event |
| International number and optional message | Open a WhatsApp conversation |
Linking to a redirect is available only for the URL type. Wi-Fi, contacts and events are encoded directly in the file. Their behavior also depends on the phone and the app scanning the QR code; a prepared SMS is not sent by the generator.
Fixed URL or linked redirect
A URL QR code can contain the destination address itself or the address of a redirect you manage. In both cases, the printed design stays fixed. The redirect adds a step whose destination you can change.
| Choice | Encoded address | After printing | Account |
|---|---|---|---|
| Direct URL | The web address entered | The encoded address does not change | No account required |
| Linked redirect | https://<host>/, at the root of the selected host | The destination can be changed in the redirect | Sign-in and an active redirect in your account required |
To prepare the second option, use domain redirect hosting. The first host is free, then each additional host costs €3 per month excluding tax. QR code generation uses this existing redirect.
The associated counter shows hits through the redirect. It does not automatically distinguish a request from the QR code from a request to the same link sent by email, and it does not measure unique visitors.
Keep the host and its redirect running for as long as your printed materials are in circulation. If you use a 301, some phones cache the destination and may keep opening the old page after your change.
Customize the design without losing readability
The settings cover colors, QR code geometry and its surrounding frame. The three large corner markers help locate the symbol; their outlines and centers have separate settings.
| Setting | Available choice | What to check |
|---|---|---|
| Colors and gradient | Solid color or two-color gradient with direction | Both colors must stay dark enough against the background |
| Background | Solid color or transparency | The final material becomes the background of a transparent QR code |
| Dots | Square, circular or rounded | Keep elements distinct at the printed size |
| Three corner markers | Outline and center shapes, colors shared with the dots or set separately | Avoid corners that are too pale |
| Logo | PNG or JPEG image in the center | Error correction automatically switches to H |
| Error correction | L, M, Q or H | Higher correction adds redundancy and can make the QR code denser |
| Size | 256, 512, 1,024 or 2,048 pixels | Allow enough pixels for a printed PNG or PDF |
| Quiet zone | Margin of 1, 2 or 4 modules | Keep 4 modules to meet the intended margin around a QR code |
| Frame and text | No frame, text below or rounded border | The text 'Scan me' can be replaced, up to 40 characters |
A module is one element of the QR code grid. Longer content can make the design denser: a short address is easier to fit on a small card than a long text.
SVG keeps the design's vector geometry. An imported logo remains an image, even in this export. PDF contains the rendered image: choose SVG if you need to enlarge the QR code substantially in a layout.
Real-world use cases
A flyer whose landing page will change
A QR code linked to a redirect keeps the same address on the flyer when the campaign page changes. Before printing, activate your redirect, sign in to the generator and choose the URL type to select it.
You can then replace a registration page with a recap page through the redirect. Check the new chain with the redirect checker. Hits measure requests through this host and should be interpreted alongside the other places where you shared its address.
A restaurant's Wi-Fi
A Wi-Fi QR code encodes the network settings so customers do not have to copy its password. Enter the details of the guest network, then test the connection on a phone that has not joined it before.
Place the poster where you want to share this access. This QR code does not go through a redirect: if you change the password or network name, you must generate and print a new file.
A business card
The vCard contact type puts your details in the QR code so the phone can offer to add them to its address book. Fill in the relevant fields, then check the name, number and email in the contact card shown on the phone.
The details in a printed vCard stay fixed. If you want a profile page you can replace, choose the URL type and link it to an active redirect. This creates a QR code pointing to a web page, with the contact details published on that page.
Points to consider
Contrast and transparent backgrounds
The generator rejects contrast below 3 and shows a warning below 4.5. This check compares the QR code colors, including the gradient and corners, with the background. A rejected style must be changed before downloading.
With a transparent background, the check uses white as its reference. A QR code that passes under these conditions may become difficult to scan over a photo or on dark paper. Test it once it is placed in your complete layout.
Margin and printing
The quiet zone must stay clear around the QR code. The reference margin is four modules on each side, as explained by DENSO WAVE. The tool warns when you choose a smaller margin.
Do not crop this area after downloading or add text to it. A fold, glare from lamination or a print that is too small can make scanning difficult even when the file is correct. Check the proof under the conditions where it will be used.
Wi-Fi data in the file
The Wi-Fi password is not saved on the server. It is sent to render the QR code, then remains encoded in the image you download. The design does not encrypt the secret.
Publishing this PNG on a public page or placing the poster in the street shares the network settings with anyone who can scan or photograph the QR code. Limit distribution to the audience you want to give this access to.
301 redirects and link lifetime
A 301 redirect can be cached by the phone or its browser. After a destination change, some devices keep the old address without contacting the redirect server again. This also limits what you can infer from the hit counter.
Test the new destination on another device in addition to using the redirect checker. Keep control of the hostname as well: the printed QR code will continue to contain that same address.
FAQ - Frequently asked questions
Q: Is creating a QR code free?
A: Yes, static QR codes are free and require no account. To link a URL to your redirect, sign in: the first redirect host is free, then each additional host costs €3 per month excluding tax. Generation remains subject to a rate limit; if you reach it, wait before trying again.
Q: Is the QR code rendered in the browser?
A: No. The browser sends the content and settings to CaptainDNS servers, which render the file and return it. Generation therefore requires an Internet connection. Once downloaded, the file can be inserted into your document.
Q: Is the Wi-Fi password stored?
A: No, the secret is processed to render the QR code without being saved on the server. It remains encoded in the downloaded file and can be read from that image. Store and share the file as you would the network access settings.
Q: Can I change the destination after printing?
A: Yes, if the URL QR code was linked to an active redirect in your account. Change the destination in the redirect while keeping its host. A directly encoded URL stays fixed; with a 301, some phones cache the old destination.
Q: Which format should I choose: PNG, SVG or PDF?
A: PNG is a pixel image suited to insertion in a document or page. SVG preserves the QR code's vector design for resizing, but any logo remains an image. PDF contains the rendered image in a document: choose a sufficient size before exporting it for print.
Q: Why does a logo require error correction H?
A: The logo covers part of the data drawn in the center of the QR code. The generator forces H to add the highest available level of redundancy. This correction does not remove the need to test the print: it does not guarantee scanning at every size or on every material.
Q: Why is low contrast rejected?
A: The dots and markers must stand out from the background. A ratio below 3 blocks generation; below 4.5, a warning asks you to increase contrast. Darken the QR code colors, including the corners and gradient, or lighten the background.
Q: Do hits correspond to unique visitors?
A: No. They count requests through the redirect, including possible repeats and requests from other links to the same host. The counter therefore does not prove how many people used the QR code. Static generation alone provides no hit counter.
Complementary tools
| Tool | Use |
|---|---|
| Domain redirect hosting | Prepare an active host whose destination you can change after printing |
| Redirect checker | Check HTTP hops and the final destination before distribution or after a change |
| Phishing URL checker | Check whether the destination URL is flagged as dangerous before printing it |
Useful resources
- DENSO WAVE - QR code quiet zone and dimensions (source linked in the printing section): understand the four-module margin and its role in the symbol's size.
- DENSO WAVE - Error correction: understand correction levels and their effect on the QR code's data capacity.
- Guide to vanity URLs, link Reporting and QR codes: more on branded links and using redirects on printed materials.