Displaying data from Postgres with ArcGIS Online

[Woodpecker]

I know it's probably a long shot, but is there any way ArcGIS Online could be set up with Postgres?

We have a fairly specific business case, where a client has to keep all the data in their Postgres database, but would love to access front-end web mapping capabilities of ArcGIS Online. Is there any way ArcGIS Online can display data from Postgres, without it being actually published to to ArcGIS Online? 

Basically, we would want all the data to stay in Postgres and only use AGOL to display it. 

Thanks!

[JayantaPoddar]

The only way I could think of, is to use ArcGIS Server (Enterprise) as an intermediate.

If you have ArcGIS Enterprise, you may Register a PostgreSQL database with ArcGIS Server, > Publish Map/Feature Service to ArcGIS Server > Add the Feature Service (not hosted) to ArcGIS Online.

ArcGIS Server web services—ArcGIS Online Help | Documentation

[Woodpecker]

Just to reply to my answer in case someone is interested in doing something similar. 

Without access to ArcGIS Enterprise and ArcGIS Server, this is probably the best solution: 

You will need to set up a GeoServer instance that will serve your data from Postgres. Use GeoServer to create WFS or WMS services, which can then be used in MapViewer and of course all other applications within AGOL that use a webmap. If you've never worked with WFS/WMS within AGOL, this is probably the best place to start.  

I tested this workflow and it generally works pretty well. Just keep in mind you won't be able to edit the data saved in Postgres through AGOL. 

It is a bit fiddly process, but it can be done if required.