Is calibre Safe? All You Need to Know

Broken passwords, leaked photos, stolen credit card numbers. Have you been affected by at least one of these crimes? I bet you did, even if you didn’t realize that. You and I both give out our private information like it’s candy. And then we must trust this data stays safe. But – as you probably heard – it doesn’t. Just this year we learned that personal information of 1 billion users of Yahoo!, 165 million users of LinkedIn and 68 million users of Dropbox were compromised. And just two years ago, we’ve seen an enormous leak of Sony Pictures correspondence and files.Personal data is stolen by hackers in large numbers.As we stay online, day and night, we also encounter bad and malicious websites and softwarePrograms that can steal directly from our devices. It’s not unusual that you wonder if calibre is safe.
Calibre is one of the most popular eBook library managers. It’s used on more than 3 million devices and is widely recommended online. Most avid eReader users have heard the name “calibre”. It’s free, it’s powerful and it’s easy to use. But what makes calibre safe? Let’s break it down.

Calibre Has No Secrets

First of all, calibre is open-source. It means that its source code is publicly available to inspect, change and distribute. You can see it for yourself on the most popular source code repository, GitHub. It might sound dangerous, but it’s not. And here’s why: every change made to calibre is checked and approved by the community of its developers. And calibre’s creator, Kovid Goyal, keeps a close watch. All calibre’s developers hang out at an open forum and you can see for yourself what they’re up to.

Because the work is so transparent, everyone who spots a problem can report it to others. Commercial software usually doesn’t allow people who don’t work for them to see the insides of their product. Fewer eyes mean fewer chances to catch a bug and fix it.

Because everyone can change calibre, it’s important to download it from its homepage. That way you can be sure it’s unchanged and safe. You can also double-check the files using checksums: they’ll tell you if the file was changed by anyone.

Calibre Does Not Collect, Store or Share Your Personal Information

Personally identifiable information about your collection, devices and usage are not collected or shared with anyone. The only data calibre will send outside your device without asking is anonymous: your IP address (just to find out in which country you use calibre), the program’s version and your operating system. If you use the news fetching feature, the only information left on calibre’s server about that is that someone downloaded news from a particular source.

This allows the developers to make calibre better suited to your needs and be sure the program runs smoothly for everyone. Compiled stats are available publicly on calibre’s homepage and no individual user’s statistics are kept.

Information About Your Device Stays on That Device

When you first connect your device to calibre, the program will scan its contents: it will check all the books and save their metadata in a file on that device. Thanks to this, you will be able to quickly check if your eBooks are already on this device or vice versa. The way calibre manages your devices can be changed in the program’s preferences.

Share Your Library Securely With calibre

If you want to send eBooks to your device without connecting it with a cable, you can email them. Using calibre you can also email eBooks to anyone else. There are two mechanisms you can use: direct mail (default) and send via a provider.Direct email sends the messages without intermediaries, using your just your computer to connect to the recipient’s host. Because this method can also be used to send fabricated emails, many email providers do not accept emails sent in this fashion.

The second method makes calibre act as an e-mail manager in that way that it uses email login information you provide to connect to your account and send the message with the eBook attached. It can be your personal account, but you can setup a separate account, e.g. on GMX. This login data is stored securely on your device and no one else has access to it. Both TLS and SSL encryption are available. Remember, that if you send your eBooks to your device using email, you will use your device manufacturer’s cloud services and they will have access to the content you sent.
Another way to share your library is to enable calibre Content Server. That way, based on your internet provider and hardware, you can set up a public or a local site that will enable guests to download eBooks straight from your computer. Calibre supports protecting this content with a username and a password you set up and makes all logs accessible only to you, so you can check who accessed what and when.

More Than Ten Years of Excellence

Since its creation in 2006, calibre has received numerous positive reviews from experts and users alike. called calibre “the best eBook manager available”, PC Advisor said that calibre “belongs on every serious e-bookshelf”, while said it’s “an all-in-one solution for handling your eBooks”. Source Forge users gave calibre 4.7/5.0 rating. It has been featured in the New York Times, the Kindle ChroniclesWired and many more.Calibre also has many options and features you can use to manage your privacy and safety of your data. You just need to dive in to the “Preferences” tab.So – don’t worry, calibre is safe. It is used by millions. It doesn’t collect your personal data. And dozens of developers strive fix any issues and harden its security. The only thing you need to remember is to download it from its official website.
This blog post was contributed by Bartosz Makuch, a Freelance Software Copywriter. He studied Physics and Management and loves to write stories that move people. In his spare time he listens to classic rock and reads sci-fi novels. You can find him at

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