where can use sandbox in InterSystems IRIS Data Platform 2025.3

You can spin up a container sandbox for playing with via Try IRIS:
https://developer.intersystems.com/iris-tutorials-for-developers/ 

Easiest way is with the community edition in a local docker container. Install docker and then run: 
 

docker run --publish 52773:52773 --publish 1972:1972 intersystems/iris-community:2025.3

You can also check out some of the dev templates which put this in a docker-compose file so you can clone a repo and run a working version with example code with just a couple of commands. You just have to make sure that in the Dockerfile it is pulling from version 2025.3 (or latest-cd). 

- ObjectScript Template

- Interoperability template

- Embedded Python Template

(theres more available on the open exchange)