Disclosure: I build Ganttry, a Gantt app for Jira, at Plug That App. Most of what follows works with any tool, and I'll say clearly where I'm talking about Ganttry.
When a release touches several Jira projects, the plan tends to end up in a spreadsheet, or in a few timelines that nobody keeps in sync. Here's what we've seen work, two Jira limits worth knowing, and what I'd check before choosing a Gantt app.
What Jira already gives you
A filter across projects is the quickest start. project in (PLAT, WEB, OPS) AND statusCategory != Done lists everything still open. Save it and you can put a board or a dashboard gadget on top of it. You don't get dates on a timeline, though.
The Timeline in a project is built around one team's epics and their child issues. It works well for a single team, less so for a plan that spans several projects.
Plans (formerly Advanced Roadmaps) can combine several boards and projects if your site is on Jira Premium or Enterprise, so look there first. It isn't available on Free and Standard, and that's usually where a Marketplace app comes in.
Tips for big plans
- Scope the plan with JQL rather than whole projects.
project in (PLAT, WEB) AND fixVersion = "2.0" keeps it to one release, and adding AND updated >= -90d drops work nobody has touched in three months. - Know Jira's rate limits. Jira limits how much any app can read from a site in a given time. Past about 20,000 issues, the first load can run into that limit. A narrower filter avoids it and is easier to read anyway.
- Keep dependencies as normal Jira issue links, like "blocks". That way every team and every tool sees the same links, and nothing is stuck inside one app.
What I'd check in a Gantt app
Speed on your biggest plan. Try it with a real plan, not a demo project, and see how scrolling, zooming and dragging feel. In Ganttry we only draw the rows on screen. The chart shows up as soon as open work has loaded, and finished work fills in after. Heavier maths like workload per person runs in a background thread, only for the dates you can see, so the page doesn't freeze while you work.
Where your data goes. Ask whether the app sends Jira data to the vendor's servers or anywhere else. Two places on a Marketplace listing answer most of this before you install: the Privacy & security tab, and the Runs on Atlassian badge, which Atlassian gives only to apps that run entirely on its platform without sending data outside it. Ganttry has that badge. It runs on Atlassian Forge and keeps plans in Forge storage, so your Jira data stays inside Atlassian. Nothing is sent to a third-party API or to servers we run. It needs Jira Cloud; Confluence is optional.
Permissions. An app shouldn't show anyone issues that Jira hides from them. Check the access an app asks for on its listing. Ganttry uses Jira's standard scopes to read and update issues, read users for the assignee picker, and let project admins edit project details. Issue reads and every change to Jira run with the permissions of the person using it.
Changes to Jira. Moving a bar shouldn't quietly change due dates your team depends on. In Ganttry, dragging, trying scenarios and comparing baselines don't touch Jira. When you're ready, you see the exact date changes and publish only the issues you pick. Other changes, like a status or an assignee, also happen only when you confirm them.
Several projects at once. Can the app plan from a board, a saved filter or a JQL query that spans projects, and does it draw dependencies between them? In Ganttry a chart can start from any of those. Before it opens, Ganttry tells you roughly how many open issues that is and warns you if it's a lot. You can also combine two or three existing charts into one view, where each keeps its own plan. If Jira pauses a very big load, you get a countdown and can cancel to work with what's already there.
What drives the date. Look for the critical path across projects, and for workload per person that counts holidays and part-time weeks.
We ship Ganttry updates several times a month, and a lot of that is interface polish based on how teams actually use it. If there's something you need that it doesn't do yet, tell me in the comments.
How do you plan work across several Jira projects today: one filter, Plans, an app, or something outside Jira? I'd like to hear what works for you.
Ganttry on the Atlassian Marketplace:
https://marketplace.atlassian.com/apps/1675319861
