Nightscout: How To Get Started With CGM in the Cloud

About a decade ago, I started connecting online with people creating their own hybrid closed loop systems, which automated insulin dosing by combining a continuous glucose monitor (CGM) and an insulin pump. As I learned more about these clever systems, I also found a supportive online community.  

When new members posted online seeking help for a problem, a more experienced user would often ask: "Can you post screenshots from Nightscout?"

As I worked to get my own system up and running I wondered, "What's Nightscout?" 

A CGM in the cloud

Nightscout is a free online service that displays blood sugar readings from a CGM device on a web page. The project started in 2013 when the parents of a child with type 1 diabetes were searching for a way to remotely monitor their son's blood sugar. 

The father, a software developer, created software that would upload CGM readings to the internet, and a number of other programmers collaborated on a visual interface that could be viewed in a browser. 

The loose collection of developers named the service Nightscout and released it to the public in 2014. Nightscout is open-source, meaning anyone can review the code behind it, which is stored publicly. The system is not regulated by the FDA and is considered experimental. 

Nightscout is a critical component of do-it-yourself (DIY) hybrid closed loop systems, allowing all treatment data – blood sugar readings, food eaten, and insulin doses – to be seen at once.

"As a caregiver, being able to check my daughter's glucose levels anytime, on any device, anywhere provides immense peace of mind," said Kate Farnsworth, an administrator of CGM in the Cloud, a Facebook community that supports Nightscout users. 

"Nightscout integrates with many other systems, can change color based on blood sugar levels, has alarms that can be customized, and has many other features that give me peace of mind as my daughter moves away from home and navigates university," Farnsworth said.

Why use Nightscout?

In 2014, no other tool existed that would allow a parent to see their child's blood sugar at school, while sleeping, or in any other situation that would be helpful to remotely monitor CGM readings. 

Today, the ability to follow blood glucose readings in real-time is a feature of every commercially available CGM. But a decade ago, the ability to do so was groundbreaking – especially for parents who had no way of following their child's blood sugar readings during the night except for waking them for a finger prick.

Nightscout would continue to evolve, allowing people to record and later view treatment data to help them make adjustments to their care. These could include the number of carbs in a meal, how much insulin was taken, and when. The data could then be viewed by the user or shared with others, including a healthcare team. Nightscout now includes reporting features that can help make sense of trends, or allow a parent to remotely deliver insulin to their child.

"Nightscout is a jewel because it captures blood sugar and insulin data side by side," said Carol Vachon, lead administrator at Loop and Learn, an online community of volunteers from around the world who support users of DIY hybrid closed loop systems.

"Knowing your blood sugar level is useless unless you know how much insulin is on board," Vachon said, referring to the amount of insulin a user has received at one time. "A blood sugar reading of 100 mg/dL is interesting, but unless you know whether there are five or 15 units of insulin circulating, you don't really have any actionable information. That's what makes Nightscout special."

Getting started

The complexity of setting up a Nightscout site can vary from very easy (by paying someone to set it up and host it for you) or quite time-consuming if you set it up yourself. For years, new users had to set up their own accounts, which was daunting but doable with the help of other users. 

Today there are a handful of providers who set up and maintain the service, and new users can get started with Nightscout in minutes instead of hours. Here is a list of service providers, with descriptions of each, maintained by the Nightscout Foundation. 

While Nightscout is primarily used by people running DIY hybrid closed loop systems, part of the appeal of the service is its wide compatibility with continuous glucose monitors and insulin pumps. (See a list of supported devices).

It's important to note that anyone willing to put in the time can still set up Nightscout for free, using directions on the main Nightscout site. However, many users (including some with advanced technical backgrounds) prefer to pay a monthly fee, which ranges from a few dollars to about $12 per month, depending on the service chosen. This route is simple, fast, and includes technical support. 

The big picture

The main view of Nightscout appears in a web browser, which can be accessed via a web address just like any other website. The user's Nightscout site can be password protected, which is recommended.

The most prominent elements seen are the time, current blood sugar level – and whether it's rising, falling, or holding steady (and if there's a change, by how many mg/dL, or for European users, mmol/L). In the example below, you can see blood sugar is 157 mg/dL and the arrow up indicates that it's on the rise. The area showing +6 mg/dL means this reading is 6 mg/dL higher than the last reading taken by the user's CGM.

The dotted line represents readings throughout the day. By reviewing the recorded readings over time, it's easier to see blood sugar trends for potential adjustment. The pale blue dotted line at right is a prediction of where blood sugar is headed. That prediction is based on the previous carbs and insulin entered.

The line at the bottom of the screen shows blood sugar readings over the day. The user can change the time frame (from two to 24 hours, as seen near the top left of the screen). Clicking or tapping the graph on the bottom of the screen will show readings over the last 48 hours.

Based on user preferences, the main screen can display basal rate over time, battery life on a pump, how long a CGM has been inserted, and many other values. The number of options available can overwhelm new users, however a good way to get to know the interface is by watching videos designed for new users, like this Nightscout basics primer, produced by the volunteers at Loop and Learn. ​​

Reports

In addition to reporting real-time data, Nightscout generates reports that can help users track hourly, daily, and weekly trends. These reports are helpful for people who want to better understand their glucose management and can also be shared with a healthcare provider. 

For insulin pump users, these reports would include how much insulin is taken for a set number of carbs eaten (carbohydrate ratio), how 1 unit of insulin will affect blood sugar (insulin sensitivity factor), and the amount of short-acting insulin delivered during the day (basal rate).

"The ability to see all diabetes information in one place is a huge feature," Farnsworth said. "The reporting available is exceptional for people living with diabetes and their healthcare providers to have daily, weekly, or quarterly views of what is happening."

Just one of the ways your data can be viewed in Nightscout is a report called "Loopalyzer." For example, a user can see insulin doses, carbs consumed, and blood sugar readings in one view over a set time period. I use this view to see my overnight CGM readings. If, for example, my basal insulin is frequently being reduced by my closed loop system, but no carbs have been consumed for several hours (not likely while sleeping), I can then see that my basal rate is likely too high and make small adjustments. 

Another excellent video from Loop and Learn walks through using Nightscout reports to gain insights. 

The bottom line

Nightscout began as a freely available, open-source service that anyone could use to view CGM readings remotely with a web browser. 

The service has evolved as a way to store and analyze all treatment data, in one place, over a time range selected by the user. Nightscout users view this data for themselves, and parents often use Nightscout to remotely monitor their children's blood sugar levels on the web via a computer, phone, or smartwatch.

Customizable alarms in Nightscout include varying color and audio alerts, which are helpful to parents as well as people with disabilities, who can connect Nightscout to devices that display low or high blood sugar via flashing lights, speakers, or devices that vibrate.

Commercially available CGM and AID systems offer remote access of blood sugar readings and don't require additional set up time or cost, but Nightscout continues to benefit users who value its ability to connect with many other different types of diabetes technology.  

A dedicated global online community continues to work together to create new features for Nightscout, as well as help users get started and troubleshoot. Nightscout's real-time monitoring and reporting tools, which analyze data over time, help users, caregivers, and healthcare providers gain actionable insights into their blood sugar levels to help optimize diabetes management.

Learn more about diabetes technology here:

• 7 Common CGM Hang-Ups (and How to Get Around Them)
• 10 Tips to Stay in Range With Type 1 Diabetes
• AID Technology Improves Diabetes Care No Matter How You Get It