A baseline is a snapshot of a set of items at a point in time. Each item is pinned at the version it had when you added it, so the baseline keeps showing that version even after the live item changes. Use baselines to mark a milestone, to send a fixed set of items to review, or to compare two states of your project later.
Baselines can include any mix of items. Each item is pinned individually at the moment it is added, so items in the same baseline may come from different points in time. Every baseline has its own version number, which goes up each time you add, remove or re-pin an item.
Creating a baseline
You need permission to create baselines. There are three starting points:
From an item's ... menu. Hover an item in the tree, document view or table view, click ... and open Baseline. Type a name into the New baseline field and press Enter.
From a selection. Select several items with their checkboxes, click the Actions button in the bar at the top, then Baseline and type a name into New baseline.
From the sidebar. Expand Baselines in the left sidebar and click + New baseline. In the Add items to a baseline window, type a title (or, if baselines already exist, open the Search baselines dropdown and type a new title there), click Add items, then pick items under Select items. Click + to add more rows and Create baseline to finish. Leaving the item rows empty creates an empty baseline.
When a selected item has children, a confirmation asks whether to include them: Baseline all pins the item and everything below it, while Baseline 1 item (or the number you selected) pins only the selected items.
Adding items to an existing baseline
As long as a baseline is Editable (not frozen or archived) you can keep adding items:
From an item's ... menu or the bulk Actions button, open Baseline and choose Add to existing baseline, then pick the baseline. Frozen and archived baselines are grayed out in the list.
Inside the baseline, click the + button at the top right (Add more items to baseline) and pick items in the Select items window.
Adding an item pins its current live version. To pin a different version afterwards, see Viewing and managing Baselines.
Parameters in baselines
A baseline can pin parameters as well as items, so a milestone also records the parameter values in force at the time. Parameters are pinned through the API. See Parameters for what a parameter is, where its value is defined and how items reference it.