Invoice Clients by Project Milestone in Flowlu
This guide covers project milestone invoicing in Flowlu: how to link each project stage to a specific billing point so the team knows when to invoice, for which deliverable, and how to confirm payment before the next stage begins.
If you need the foundational steps, how to send an invoice covers those. This guide is about milestone based invoicing: tying payment to delivery, not to calendar dates.
Quick answer
Set up a milestone in Flowlu for each billing point, note what's owed against it, and create the invoice manually from the project's Finance tab when the milestone is checked complete. Every partial payment logs to the project automatically, and you can check outstanding balances without leaving the project view.
What this guide helps you set up
- A milestone for each billing point, named after the deliverable it represents
- Payment amounts and terms recorded against each stage before the project starts
- A clear trigger for when each invoice goes out (milestone completion, not a calendar date)
- One place to see all invoice statuses across the project
What a milestone billing workflow should achieve
Milestone billing works when everyone has the same information: your client knows what each payment covers, your team knows when to send the invoice, and the record shows clearly what's been paid versus what's still open. Miss any one of those and payments slip.
Why milestone billing breaks
Most billing delays trace back to the project workflow, not the invoicing tool.
Project stages and billing points are not aligned
A common setup: the project runs in Flowlu, the billing schedule lives in a spreadsheet, and the original agreement is in an email from six weeks ago. Nobody checks all three when a milestone is done. An invoice goes out late, with the wrong amount, or not at all.
Invoices are sent too late or without context
Send an invoice a week after a project phase ends with no mention of what was delivered, and you'll spend the next few days explaining it. The client doesn't remember what was agreed. Your team can't easily pull the context. Payment terms reset and the next project stage starts in limbo.
Teams lose track of what has already been billed
By the third billing milestone on a 4-milestone project, someone will ask: did we invoice for phase 2? Was that paid? The answer is usually "I think so" or "check the spreadsheet." On a live project, those are bad answers.
What milestone billing should include
3 things need to be in place before the project starts. Without them, even a clean billing setup in Flowlu won't close the gap in your milestone invoice process.
Clear billable milestones
Milestone based invoicing depends on milestones being checkable. Design approval, development handoff, final delivery: these work because both parties can confirm they happened. "Substantial progress" or "phase mostly done" don't, because completion becomes a matter of opinion when money is involved.
Agreed payment logic for each milestone
Billing by project milestone only holds up if the client agreed to the terms before work started. The amount per stage, the payment window, what specifically counts as completion for each phase: these need to be confirmed up front. Once the invoice lands is a bad moment to have that conversation.
Visibility into invoice status and the next billing point
Once invoices are sent, the team needs somewhere to see which ones are outstanding. The project management invoice workflow in Flowlu keeps delivery and billing in one view, so there's no switching between tools to check what's been paid.
How to invoice clients by project milestone in Flowlu
Here's how to invoice clients by project milestone in Flowlu. 4 steps, from project setup to payment confirmation before the next stage begins.
Step 1. Define billable project milestones
In Flowlu, open the project and go to the Work Structure section. Add a milestone for each billing point. Name it after the deliverable: "Discovery complete," "Phase 1 delivery," "Final handoff." Make the name specific enough that everyone knows what was done and when.
Add a start date so the expected completion is visible on the project timeline. When the milestone is checked as complete, Flowlu records the exact completion date automatically; that's your cue to create and send the invoice for that stage.
Note the billing value in a custom field or the milestone description so anyone on the team can see what each stage is worth without hunting through the contract.
Step 2. Confirm milestone payment terms with the client
Before work begins, write down the billing schedule for each milestone inside the project in Flowlu. A project note works fine. An invoice template works too. The point is that it lives inside the project record, not in a separate document nobody will find when it matters.
What to capture: the amount or percentage due at each project stage, the due date (7, 14, or 30 days from invoice date, whatever was agreed), and what counts as completion for each billing point.
Client sign-off, file delivery, client approval in the portal: pick one per milestone and write it down. No ambiguity when it's time to create the invoice.
Step 3. Create and send the invoice at completion
When the milestone is checked as complete, go to the Finance tab in the project and click Create to generate the invoice. Flowlu links it to the project automatically. Set the due date based on the agreed payment terms, then send with a short note referencing which milestone the invoice covers.
That note matters more than it seems. Clients who can see exactly which deliverable an invoice maps to pay faster than those receiving a line item they have to match to a project phase on their own.
Step 4. Track payment status before the next stage begins
After sending, check the Invoices & Estimates section in the project's Finance tab. That's where all project invoices live with current payment status. The Money section shows estimated revenue vs. what's actually come in, and the balance still owed.
Confirm payment before the next milestone kicks off. If a payment is overdue and the team is ready to start the next phase, that's the moment to follow up; do it before more work is delivered, not after.
A consulting firm running a 3-phase website project sets up 3 milestones in Flowlu: "Discovery and strategy," "Design approval," and "Final delivery." Each has a billing value noted in the milestone (30%, 40%, 30%) and a 14-day payment term in the project notes.
When Discovery is checked as complete, Flowlu logs the completion timestamp. The team opens the Finance tab, creates the invoice, references the milestone, sets the due date, and sends.
Before Design starts, someone checks the Invoices & Estimates section: paid, move on; overdue, follow up first. Same process at every stage. By final delivery, every partial payment is accounted for and traceable.
Common mistakes in project milestone invoicing
Using vague milestones that are hard to bill against
"70% complete" is not a billable milestone. Neither is "phase 1 mostly done." If completion can't be confirmed without a conversation, it won't hold when the invoice lands. Clients will push back, and they'll have a point. Keep milestones tied to concrete, verifiable deliverables.
Sending invoices before milestone completion is clear
Sending the invoice before the deliverable is formally confirmed is the fastest way to create a dispute. Maybe there are outstanding revisions. Maybe the client expected something different. Invoice after written confirmation: an email, a portal approval, a signed-off checklist item. Not when you think you're done.
Letting billing terms live outside the workflow
Payment terms buried in the proposal PDF are functionally invisible by month 3 of a project. Nobody looks. Put the terms in the project notes at the start. When the next invoice is due, they'll be exactly where the team needs them.
Final takeaways
What the minimum workable milestone billing system looks like
Strip it down: milestones with clear completion criteria, payment amounts noted against each one, and a consistent rule for when the invoice goes out. That's the whole system. Everything else is optional.
What to standardize first in Flowlu
Start with milestone names. If every project uses the same labels (Discovery, Development, Delivery), you can build invoice templates that map to each one directly. That's where how to bill by milestone stops being a per-project decision and becomes something the team just does.
Set up milestone billing so project progress and client invoicing stay aligned. The invoicing features in Flowlu cover everything you need to connect delivery to payment in one place.
Milestone billing ties each invoice to a completed project phase, rather than a fixed schedule or a lump sum at the end. When a defined deliverable is done and confirmed, that triggers the payment for that stage. It's common in agencies, consulting, and any service work that runs in phases.
To invoice clients by project milestone: agree on the billing points and amounts before work starts, document them in the project, and create the invoice when each milestone is completed and confirmed. In Flowlu, you do this from the Finance tab inside the project. Monitor payment status in the project's Finance tab before moving to the next project stage.
It needs to be something both parties can confirm as done. A completed design phase, a signed-off document, an approved handoff: these work. "Substantial progress" doesn't, because it's too easy to dispute. If you can't point to a specific deliverable and say it was delivered and confirmed on a specific date, it's not ready to be a billing trigger.
