Timeline

Plan your project and track key dates, milestones, and deadlines.

Your timeline is where you plan your projects and track key dates, milestones, and deadlines. It gives your team a clear view of what's being delivered and when.

You can also add your clients as Viewers or Contributors on a project to give them read-only access, making it easier to collaborate with external stakeholders.

Weekends are hidden by default, and UK public holidays are highlighted. You can toggle either from filters if needed — especially useful when working with international clients who may not be aware of your local holidays.

A quick tour of the Timeline view.

Building your timeline

To build your timeline, start by adding project deliverables directly. Type where it says Add new deliverable in the first row of the Gantt chart.

Adding a new deliverable directly on the timeline.

Tip

If you have already created a quote and it has been approved, you can save time by importing deliverables from the Tasks tab. This pulls line items from an approved quote and automatically prepopulates the deliverables for you. You can then edit the work window allocated to each deliverable.

By clicking on a part of the timeline, you can:

Change timeline colours
Add dependencies
Duplicate line items
Ctrl/Cmd-click (or Shift-click) multiple bars to select them together, then drag any one — the rest move in sync. Handy when a whole phase slips by a week and you don't want to reschedule ten deliverables one at a time.

Milestones

Milestones mark a single important date on the timeline — a launch, a client sign-off, a hard deadline. Each one draws a dotted vertical line across the whole chart with a coloured label at the top, so a fixed date stays visible against every deliverable at once.

There are two ways to add one:

Click any date in the timeline header. The milestone opens with that date already filled in, so you only type a name.
Use the flag button in the toolbar and pick the date yourself.

To change or remove a milestone, click its label. The same panel opens with the current values and a Delete button.

Each milestone takes a name, a date, a colour, and an optional note that appears when you hover the label. Where several milestones share a date, their labels stack, and a +2 marker appears once there are more than three.

Milestones appear in PDF and image exports, with one difference from the screen: where several milestones share a date the export shows all of their labels rather than the first few and a +N count, since a document cannot be expanded. They are also captured in saved timeline versions — restoring an older version restores the milestones it held.

Tip

A milestone dated beyond your last deliverable still shows up — the timeline widens to reach it, so a launch date six months out is never off the edge of the chart.

Adding a milestone to a project timeline.

Dependencies

Dependencies are created by dragging from one task bar to another. The task you drag from is the blocker, and the task you drag to is the one it blocks. Trellis treats every dependency the same way: this task must finish before that one can start.

Dependencies are most useful for modelling handoffs — one team's output being the next team's input. Design to build, build to QA, QA to launch. Once the links are in place, the timeline visually holds the story of what depends on what.

If Build depends on Design, and Design's dates slip so it now finishes after Build was meant to start, the line between them turns red. Trellis flags the broken order so you stay in control of how to resolve it — reschedule Build, compress Design, or renegotiate scope. The decision stays yours, but the plan won't quietly go stale.

Which dot you drag from doesn't matter — both edges of the bar work the same way, and the direction of the drag decides who blocks whom.

Dependencies and milestones can also be managed by Trellis AI or an MCP client — useful for setting up a run of links in one go rather than dragging each one.

Timeline showing dependencies between deliverables.

Managing your timeline over time

Throughout your project, your timeline may shift. To keep track of these changes, regularly save your active timeline.

You can switch between past and current versions to see how the plan has evolved and how many times a deadline has moved. When you open a saved version via the clock icon, the previous plan appears as transparent ghost bars over today's timeline — the fastest way to answer "how much has this deadline moved?" in a client retro.

Switching between saved timeline versions.

Use the export panel in the top right to send your plan out as a file:

Export as image (PNG) — great for slide decks, kickoff docs, or a quick screenshot into an email
Export as PDF — a paginated, printable version for formal client reviews or sign-off

Timeline export panel with PNG and PDF options.

When a timeline is too big to export as an image

A long or busy timeline can exceed what a browser is able to render into a single image. Rather than let you wait on an export that was always going to fail, Trellis now sizes the image up front: if it's over the limit, choosing Export as image (PNG) opens a prompt offering the PDF instead. Download PDF runs the PDF export there and then; Cancel leaves the timeline as it was.

Prompt offering a PDF export when a timeline is too large for an image.

Tip

PDF has no such ceiling, so it's the reliable choice for a whole-project plan or a long date range. Narrowing the exported range, or hiding weekends, brings a timeline back under the image limit if you specifically need a PNG.

Separately, exports cover at most 730 days whichever format you pick. A timeline spanning more than that is refused outright, with a "Timeline too long to export" message — narrow the range and run it again. Both limits apply to anyone exporting from a public link too.

Share, next to the export panel, covers both audiences a plan usually has.

Keep private hands you the in-app link. It always reflects the latest plan, so colleagues aren't chasing an out-of-date attachment — but opening it needs a Trellis account with access to the project.

Create public link hands you a link that opens without an account at all. It's the option for a client or an external stakeholder who shouldn't be a project member just to watch dates move. What they see is the current plan every time they open it, read-only, and they can export it as a PNG or PDF the same way you can.

What travels: deliverable names, their dates and colours, the dependency links between them, and your milestones — name, date, colour, and the milestone's note, which a viewer sees when they hover the label.

What doesn't: task descriptions, assignees, statuses, estimates, and comments.

The public view always hides weekends and shows public holidays, whatever you have set on your own timeline — the recipient's calendar filters are fixed, not inherited from yours.

Warning

Milestone notes are visible to anyone holding the link. Keep internal context — budget worries, client politics, anything you wouldn't say on a call with them — out of the note before you share a timeline.

Creating a public link for a project timeline.

A project has one live public link at a time, so everyone you send it to is holding the same URL. Generate new link replaces it and the old URL stops working immediately — for every recipient, not just the one you had in mind — so anyone who still needs the plan has to be sent the new link. Switching back to Keep private closes the link the same way, and neither a replaced nor a closed link can be brought back.

Warning

Archiving a project takes its public link offline — Trellis warns you first if one is live, so a client's link doesn't quietly go dead. Restoring the project brings the same link back.

Who can do what

Action	Owner	Admin	Editor	Member	Contributor	Viewer
Open the Timeline				^*	^*	^*
Add deliverables directly or import from an approved quote	^*	^*	^*	^*	^*
Change bar colours, add dependencies, duplicate lines, or multi-select bars	^*	^*	^*	^*	^*
Add, edit, or delete milestones
Duplicate a deliverable from the click menu	^*	^*	^*	^*	^*
Delete a deliverable from the timeline	^*	^*	^*	^*	^*
Save an active timeline as a version and switch between saved versions
Export the timeline as PNG or PDF
Copy the in-app timeline link, or create, replace, and close a public link	^*	^*	^*	^*

* Project membership required. Members, Contributors, and Viewers can only open a project they've been added to, and every starred write needs membership from every role — Owners and Admins included. Trellis offers to add you when you hit one. A workspace Owner or Admin who hasn't joined the project can still read and export the timeline, add milestones, and save or restore versions — it's the starred deliverable, dependency, and share-link actions they're refused until they join.

Viewers see the timeline in read-only mode — they can browse deliverables and milestones, use filters (weekends, holidays), and export the plan, but can't add or edit anything on it. Every other role has full editing access. This is exactly why adding clients as Viewers or Contributors gives them a useful read-only window into your timeline for external collaboration.