Atlassian Connect allows you to create extensions (integrations or plugins, depending on how you prefer to call) and is not necessary if you just want to make some requests for endpoints jira.
As already pointed out in comments, there is a overflowing documentation in the developers section.
The first thing to consider is what kind of service you’re dealing with, that is: Cloud (hosted by Atlassian) or Server (installed in your company).
Depending on what you want, the difference between such versions will be only the authentication method, but usually you can use basic HTTP authentication, only need to have or seek to obtain the necessary credentials.
For example, if you want to consult pending (issues) of a project, there is an API that allows you to run whichever query JQL via REST and get the result in JSON. Use any language for this.
In the case of jira.spring.io, I tested the following command to search all bugs to the project spr
:
curl -X POST -H "Content-Type: application/json" --data \
'{ "jql": "project = spr AND issuetype = \"bug\"","startAt": 0,"maxResults": 15,"fields": ["summary","status","issuetype"]}' \
https://jira.spring.io/rest/api/2/search
The cool thing is that it works anonymously, without needing credentials, because it is a public project.
You can customize the search for your needs and also search others endpoints if you need other information.
In itself website has tutorials on how to use the api
– Costamilam