How Data Flows Through Nightscout

Understanding how data moves through Nightscout makes setup and troubleshooting much easier.

This page explains the flow at a high level.

The basic data flow

In most setups, data follows this path:

CGM or pump
→ Uploader or APS app
→ Nightscout
→ Followers, caregivers, reports

Nightscout sits in the middle as a secure data hub.

Uploading data

Your CGM or pump does not usually talk to Nightscout directly.

Instead:

• An uploader app or APS app collects the data
• That app sends data to your Nightscout site
• Nightscout stores and displays the data

If data stops updating, the issue is usually with the uploader or connection, not Nightscout itself.

Viewing and following data

Once data reaches Nightscout:

• You can view it in a browser
• Caregivers can follow using apps
• Smart displays and watches can pull data
• Reports can be generated

Nightscout does not change the data. It displays what it receives.

APS specific flow

When using Loop, Trio, or iAPS:

• The APS app uploads glucose, insulin, and profile data
• Overrides and profile changes are sent from the phone
• Nightscout reflects what the APS provides

Nightscout does not calculate insulin delivery in APS setups.

Why this matters for troubleshooting

Understanding the flow helps answer common questions:

• If no data is showing, check the uploader
• If data is delayed, check connectivity
• If a setting does not change, check where it is controlled
• If followers cannot see data, check access settings

Nightscout Pro ensures the hosting side is stable so issues are easier to isolate.

In summary

• Nightscout is a hub, not a controller
• Uploaders and APS apps send data in
• Followers and reports read data out
• Most problems occur at the edges, not the centre

Knowing this saves time and reduces frustration.