How to Build an AI Invoice & Billing Agent
An AI agent that creates invoices, chases late payments, reconciles accounts, and gives you a cash flow snapshot — all through email.
When a payment lands, the agent posts to Slack:
How it works
Create a billing agent at dashboard.carlyassistant.com. Connect your accounting software, payment processor, and email — QuickBooks, Stripe, and Gmail cover most setups. The agent creates invoices, sends reminders on a schedule you define, matches incoming payments, and delivers AR reports on demand. Full walkthrough: How to Create a Custom AI Email Agent.
What an AI invoice agent connects to
Accounting: QuickBooks, Xero, FreshBooks, Zoho Books, Zoho Invoice, Zoho Inventory, Moneybird, sevDesk, FreeAgent
Payments: Stripe, Square, Flutterwave, Lemon Squeezy
Email: Gmail, Outlook
Messaging: Slack, Microsoft Teams
Spreadsheets: Google Sheets, Microsoft Excel, Airtable
Storage: Google Drive, Dropbox, Box, SharePoint
See the full list of integrations.
What an AI billing agent can do
- Bill a client when a matter closes — tell the agent the matter, hours, and rate; it builds the invoice in QuickBooks with itemized time entries, emails it with a payment link, and tracks it through to payment
- Chase retainer replenishments automatically — the agent monitors retainer balances and sends escalating reminders when they drop below threshold, so no work starts on an empty trust account
- Run monthly trust account reconciliation — the agent cross-references IOLTA deposits against open matters, flags discrepancies, and delivers a summary you can hand to your bookkeeper
Build your billing agent in under 10 minutes at dashboard.carlyassistant.com, or email carly@usecarly.com and describe the agent you need.
Related: How to Build an AI Bookkeeper | How to Build an AI Email Triage Agent | How to Create a Custom AI Email Agent | Best AI Tools for Solopreneurs | How to Build AI Employees
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See what people say
"Before Carly, I relied on a Calendly link, but the whole process felt impersonal and not very professional. Carly changed that by handling all the back-and-forth, so I'm no longer stuck in endless email threads trying to line up schedules.
Now Carly reaches out to candidates, shares my real-time availability, lets them pick a slot, then sends a Zoom link and drops it straight into my calendar. She sends reminders to both of us before each call, which has significantly reduced no-shows and last-minute confusion.
On top of scheduling, Carly acts like a full executive assistant, sending me my schedule the night before so I can prepare for each call. It reminds me of the old x.ai assistant, but Carly is noticeably smarter, faster, and better suited to my healthcare recruitment business."
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