Q. What is Siilo?

Siilo is the secure messenger for healthcare. Medical professionals and teams can communicate and share information in a secure, encrypted environment. It is our mission is to connect you with your peers to discuss challenging cases together, share the latest news and views, and stay on the ball when a patient requires that extra attention during your busy work schedule.

Q. What is a Siilo? Why are you called Siilo?

Siilo is Finnish for "silo." Silos are vertical structures that carry one-of-a-kind material, e.g. grain. Figuratively speaking, silos are groups of people from one department, profession or background. In (healthcare) management, the word silo is oftentimes negatively used to describe a group of people who do not share information with others. In medicine, silos are both a curse (silos prevent collaboration) and a blessing (sensitive information does not flow freely). Siilo contains two i's referring to our mission to strike the perfect balance between collaboration and information security between classic silos in healthcare. In addition, Siilo is our acronym for Secure Internet Information Liaison Or something like that.

Q. What can I do with Siilo?

You can use Siilo to manage your workflow, or manage care for your patients. Siilo is also used for medical crowd sourcing, i.e. asking a group of trusted peers for advice on challenging cases. Siilo can also be used as a portfolio tool and share cases for educational purposes.

Q. Why should I use Siilo?

Not using WhatsApp in healthcare should be a no-brainer by now. Signal is very secure, but was not designed for healthcare. Sure: your data in transit is secure, but what about your data at rest? Signal stores data indefinitely, and trespassers can enter the app if your phone is unlocked. Besides, Signal can not remotely wipe your data when your device is compromised. Signal or other general secure messengers out there don't have tools for you in place to blur identifiable information, and you cannot set up your professional profile, which are all very important features in healthcare.

Q. Why is Siilo secure?

Secure messaging means that we implement strong (state-level) open source end-to-end encryption protocols for your data-in-transit. We implement smart features so that data can be stored in an encrypted vault within the app. So your data-in-rest is also encrypted, and access to the app is blocked with your PIN-code. However, we strongly advise you to also lock access to your phone with a strong passphrase/ PIN-code. This is really important to keep the data on your phone secure.

Q. Why was Siilo developed?

Siilo was developed to empower physicians and other healthcare professionals to truly practice medicine together and provide better healthcare. The basis of practicing medicine together is to be able to collaborate seamlessly, and seek each others' advise and expertise, independent of each other's location or availability.

Q. Where is Siilo developed?

Siilo software is developed at our office in Amsterdam, The Netherlands.

Q. With whom can I use Siilo?

Siilo is a cross-platform communication tool for healthcare, so you can use Siilo with anyone with an Android or Apple device.

Q. Can I use Siilo to communicate with patients?

No. Siilo is developed for communication between healthcare professionals only.

Q. Why should I trust Siilo?

Siilo is a start-up that has evolved around an array of experts that are truly unique in the healthcare ICT arena. We are a collection of medical professionals who teamed up with entrepreneurs from the mobile messaging arena, talented software engineers who have been building messengers for the past 10 years, world-renowned cryptographers, esteemed medical law specialists and successful healthcare entrepreneurs.

Q. What can we expect from Siilo in the future?

We are just getting started, and we are putting a 100% effort into making Siilo a superior chat experience for you and your colleagues. Soon we will diverge into other features that will save you time in your daily practice.

Q. I represent a healthcare organization. What should I look for when selecting a secure messenger for our workforce?

Selecting a secure messenger for your whole organization is a process that involves a lot of variables. These are not the same for every organization. If you have any questions or need help in this process, please reach out to us at

Q. Is Siilo ISO-27001 certified? Is Siilo HIPAA compliant?

Siilo implemented an information security management system according to the ISO-27001 (and NEN-7510) standard. We expect our first external audit and certification in Q4 of 2016. If you would like to know more about this, please send an email to We will also provide our Whitepaper on HIPAA in the future. We will keep you posted on this subject.

Q. Why does Siilo ask permission to access my contacts? Are my contacts saved on your servers?

No. Although we periodically upload your contacts to see whom of your contacts is using Siilo, we will never save and store your contacts on our servers. Immediately after uploading and matching the numbers with other users, we discard the hashed phone numbers.

Q. Why does Siilo need to know my phone number?

We do this so that you can easily find other users on Siilo that you already know. Your Siilo identity is based on your phone number, similar to programs such as WhatsApp and Signal. We will never identify you as your actual phone number though – only an unrecognizable, hashed and padded version of it.

Q. I would like to be verified. How do I do that?

The verification process starts with the verification of your email address, so please click on the link in the email that we've sent you. From there we continue the verification process and contact you in case there are questions from our side. We use the information that you fill out on your profile as well - and that speeds up the verification process. You can see if a user is verified in your contact list and on his/her profile page. Unverified professionals will be eventually blocked from the Siilo platform.

Q. What is the difference between a verified and non-verified user?

Siilo is a platform for medical professionals. Therefore, we will verify all users that download the Siilo app. A non-verified user is a new user in the process of verification. If we fail to verify you, we will remove your account and remember the phone number you registered with.

Q. Why does Siilo ask for my institutional email address?

Siilo will verify who you are and what it is that you do in healthcare. That process is initiated with your institutional email address as it may provide the first proof of being a healthcare professional.

Q. Do I have to fill out my profile? How do I do this?

Yes. When you engage in discussions about cases, participants in that discussion must understand who you are and what your area(s) and level of expertise are. Also, it makes it easier for us to verify you as a healthcare professional. Filling out your professional profile is easy. Just go to settings and tap on your name (iOS) or "edit profile" (Android). Fill out your headline: this is what you would say to introduce yourself over the phone. You can use free text format to explain your specialty as well as your interests. This will be used later for other users to find your expertise on the platform if you opt-in for that feature.

Q. Who are in my Siilo contact list?

The Siilo contact list is composed of the contacts in your phonebook who also installed the Siilo app. In addition, participants of your group chats are added to your Siilo contact list. And it is possible that your number is listed in someone else's phonebook, while you do not have this contact in your phonebook. Also, in that case we add that contact to your Siilo contact list.

Q. How can I invite a colleague to use Siilo?

You can invite colleagues directly through the contacts section of the Siilo app. You will be directed to Whatsapp with a prefabricated invitation to download Siilo from the App Store/ Google Play Store using the link. If you are talking to another professional over the telephone, and neither of you have each other's phone numbers, at least one of you will have to add the other's phone number to his/her address book (similar to WhatsApp or Signal) to automatically connect on Siilo.

Q. After downloading and installing the Siilo app, I see someone I know, however I do not have their phone number. How is this possible?

When using the Siilo app, we periodically scan your phonebook for matches with other Siilo users. It is possible that your number is listed in someone else's phonebook, while you do not have this contact in your phonebook. Also, when you are in a group chat with people you do not have a phone number of, they will also appear between your contacts on Siilo.

Q. I want to change my name - how do I do this?

You cannot change the name you registered with. So if it has a typo, or you changed your name: reach out to us on and we can solve that issue for you.

Q. How do I start a conversation with a colleague?

From the contacts section in the app: tap on the name of the person you want to engage with. This will open a conversation with that person. From the chat overview: tap on the name of the person or group that you previously engaged with. It will get you right into that conversation.

Q. How do I start a new group conversation?

From the chat overview you can initiate group conversations by tapping the "compose message" icon. On the top of your contact list you see "create a new group." The select the participants (can also be only 1 person), and come up with a group name. Tap "create" to start conversing with the participant(s).

Q. What can I do as an admin of a chat group?

As the "admin" of a group, you can add or remove participants and change the name of the group. In the near future, you can select to opt-out from the default ephemeral messaging.

Q. Can I mute notifications from a specific chat?

Yes. In the settings section of the app, you can select to mute the sounds/vibrations of the notifications of all incoming messages. In the near future you will be able to mute the sounds from a specific chat in the chat overview.

Q. Why can I not see a part of the message in the push notification?

We cannot display content of the messages you receive in the push notifications because of the encryption. The decryption process is initiated when you enter the app, using your PIN-code. So there is no way for us to know what to put as a preview of the message in a push notification.

Q. What is the pinboard for, and how do I use it?

The pinboard is the secure vault within the app where all your images are securely stored. You can also access the camera here to capture and store images immediately in this vault, without having to send them. You can manage your files here and find them compiled for quick reviewing.

Q. Can I use Siilo on my desktop computer?

Not right now. However, we are currently in the process of designing our desktop client. We will inform you when we are in the testing phase, and we may need your help with that!

Q. Can I use Siilo on my smartwatch?

Our push notifications are delivered on your wearable. However, the watch does not contain the private key that is necessary to decrypt/encrypt messages. Only your phone has that ability, so you can't read and send messages on your watch.

Q. I would like to use Siilo on multiple devices, e.g. my iPad. Is this possible?

No. At this moment, we do not support multiple devices, such as tablets. However, we are working towards a desktop client. We will keep you posted about this.

Q. How can I take a picture in Siilo, and how can I be sure that these images are securely stored, separate from my personal photo's?

You can take a picture in a conversation. This image will be automatically saved in the secure vault in the app, called "pinboard." You can also take pictures with the app without sending it to another user. The pinboard allows you to select the camera option, and the images will appear on the pinboard. Everything in your pinboard is encrypted with your private key. No third party can access your data on the pinboard, unless they know your PIN-code.

Q. Where does Siilo store my pictures and video's?

Pictures and video's will be stored encrypted within the app on your phone. It is not possible to access these files without your private key.

Q. How do I anonymize a picture?

You can blur faces, special tattoos and names or birth dates with tools within the app. After opening or snapping an image, you can select the "edit" icon. You can blur parts of an image, or place an arrow. On Android you can tap "undo", or "undo all." On iOS you can double-tap to remove a blur or an arrow. Tap "save" before sending the image to your colleague.

Q. How do I highlight something in the picture with an arrow?

You can put an arrow in the image by selecting the "edit" icon when you are at the image. You can place an arrow when you select that option. On Android you can tap "undo", or "undo all." On iOS you can double-tap to remove an arrow. Tap "save" before sending the image to your colleague.

Q. How can I import a picture from my camera roll into the secure vault of Siilo?

In the pinboard section you can select a "+" (iOS) or a camera roll icon in the upper right corner. This will lead to your camera roll and you can select the image you want to import. The multi-select option to import multiple pictures at once will come soon.

Q. Why is a PIN-code required to open the app?

The PIN-code is to block unwarranted trespassers when your phone is unlocked. When one enters the code incorrectly 3 times, the app will be blocked for 3 minutes. After that, the app will be blocked for 15 minutes after the PIN-code was entered incorrectly. You can always enter the app directly during these blockages with your fingerprint.

Q. I forgot my PIN-code: what do I do now?

Uh oooooh. This is bad. Because losing your PIN-code means losing all your data and some contacts. You will have to unregister your account and sign up again. To unregister, you will have to reach out to us on with subject "lost PIN-code". Please include your phone number so we can call you.

Q. How do I know that my messages are encrypted?

We do not want you to notice anything of our high-level encryption. So you will not notice that this encryption happens all the time: when you send a message, when you open a new message, every time you open the app, when you go to the pinboard, etc. Only when you send a message to a user that uninstalls and reinstalls the Siilo app on their (new) phone, he/she will be unable to decrypt your message. However, when you resend that message, that user can decrypt the message again.

Q. Are pictures, voice messages and files also encrypted?

All the data you exchange is encrypted with your secret key from your device to the device of the receiver, even in group chats of 300+ participants.

Q. I would like to switch to my new phone. What should I do?

If you do not wish to lose your data, a data backup should be performed to allow you to move your chats, groups and contacts to your new or reset phone. In our public beta, we do not support this feature yet.

Q. I have lost all my data! Can it be recovered?

We don't have access to your data. If you would like to restore your messages or contacts, you will need to perform a backup with a strong password. If some of the information is missing, your data is not accessible anymore. We are sorry for this, but that is the price you pay for a secure product.

Q. I have deleted the app from my phone, but my colleagues still see me in their contact list. How do I delete myself from the Siilo platform?

You have probably just deleted the app from your phone's homescreen. However, to remove yourself properly from the Siilo platform, you should go to settings and select "unregister" to remove yourself completely.

Q. Are my messages saved on your servers?

Servers are required to temporarily hold your messages until the receiver comes online (who opens the app with a PIN-code) and retrieves the message. We do not store messages longer than that. Upon delivery, they are immediately deleted from servers, with a maximum lifetime waiting to be picked up by the receiving end of 30 days.

Q. How should I keep my phone secure?

We advice the following to keep your phone secure: 1. Regularly update your software (OS and apps) 2. Use a pin, password or pattern to lock your phone 3. Set up a SIM lock, other than '0000' 4. Download apps only from trusted stores

Q. Why doesn't Siilo support "self-destruct" or a "recall message" functionality?

Setting timers on a message lifespan will only give the false sense of security, as the receiver is always capable to capture the message through a screenshot (on iOS, not on Android). We believe that seeing a ticking clock will actually stimulate users to snap screenshots, just to be sure. Therefore, we do not implement such features, as they will most likely result in data-leakage from the secure Siilo app into the Photos App.

Q. How do I know for sure that I have the right person on the other side?

If you have just added a colleague's phone number in your phone's address book to start messaging on Siilo, please start the conversation by first saying "hello." This is to make sure that you have actually entered this person's number correctly and started communicating with the right person. Similar to good-old fax machines, a fat-finger error is easily made, and it would be a shame if you sent your patient's EKG to the wrong person. Chances that the other person is also on Siilo is pretty slim however.

Q. Can I open the app using my fingerprint?

Yes. If you choose to, and if your device supports it, you can use your fingerprint to enter the app.

Q. How can I be certain my messages are sent securely?

The times where one could just answer to these types of questions with "Trust me, I'm a doctor" are no more. We use state-of-the-art open source crypto software, and we will open source our messenger engine software in the near future so anyone can review our implementation and see if we have built-in backdoors. For now, we work with independent ICT security companies with an impressive track record to audit and review our software.

Q. How do you handle my profile and contact information?

Your privacy is very important to us. Your contact information (hashed phone number, email address) and your profile information will never be sold, shared or revealed to anyone except our Siilo user verification unit. In the future, you may opt-in for features that would require us to contact you using this information.

Q. When I leave my phone somewhere, can everybody then see my messages and pictures in the app?

You should never leave your phone behind unattended, just like you don't leave used needles lying around. But if it happens by accident, nobody but you should be able to unlock your phone. And if the phone hasn't locked itself yet, your data is protected with your Siilo PIN-code.

Q. What is ephemeral messaging? How does that work?

Ephemeral messaging uses volatile messages. In other words, the messages are automatically deleted after a pre-set time. So when a message is sent on Siilo, the message is immediately deleted from the servers when it is delivered. The message then 'lives' on the sender's and receivers' phones, but only for 30 days. That means if you wait 31 days to come online and pick up messages from the server, you will never get them.

Q. How long are the messages and other media (pictures, movies and voicemails) saved on my phone?

The default process is that all messages and media files are automatically deleted from your phone after 30 days. However, in the group chat creation process, you can choose to exempt from the default ephemerality. This allows a group to create a database with case discussions that you can search.

Q. Am I allowed to send identifiable information about my patients over Siilo?

Yes, you are. But before you do, you should be very aware with whom you may do this, and in what manner, as it depends on several factors. Please read our 'legal white paper' on this subject and our blogposts about this subject.