How to Use OpenClaw for Invoice Automation

Invoice Automation Without the Overhead

For freelancers, consultants, and small agencies, invoice management is one of the biggest time sinks. OpenClaw can handle the entire cycle: generate invoices, send them, track payment status, and follow up on overdue ones — automatically.

The Core Stack

• Stripe: Invoice creation, payment tracking, customer management
• Resend: Email delivery for invoices and reminders
• Google Sheets (optional): Invoice log and tracking

Create Invoices via Stripe API

Add Stripe to your TOOLS.md:

### Stripe Billing
- Base URL: https://api.stripe.com/v1
- Auth: Bearer $STRIPE_SECRET_KEY
- Key operations:
  - POST /invoices (create invoice)
  - POST /invoiceitems (add line items)
  - POST /invoices/{id}/send (send to customer)
  - GET /invoices?status=open (list unpaid)

Create and send an invoice:

# Create invoice for existing customer
curl -X POST https://api.stripe.com/v1/invoices \
  -u $STRIPE_SECRET_KEY: \
  -d customer=cus_xxxx \
  -d collection_method=send_invoice \
  -d days_until_due=14

# Add line item
curl -X POST https://api.stripe.com/v1/invoiceitems \
  -u $STRIPE_SECRET_KEY: \
  -d customer=cus_xxxx \
  -d invoice=in_xxxx \
  -d amount=500000 \
  -d currency=usd \
  -d description="Consulting services - March 2026"

# Finalize and send
curl -X POST https://api.stripe.com/v1/invoices/in_xxxx/send \
  -u $STRIPE_SECRET_KEY:

Automate Monthly Invoicing

Set a cron for the first of every month:

openclaw cron add \
  --name hex-monthly-invoices \
  --schedule "0 9 1 * *" \
  --agent main \
  --task "Create and send monthly invoices for all active retainer clients from the clients list in TOOLS.md"

Keep your client list in TOOLS.md or a Google Sheet your agent can read.

Overdue Payment Follow-Up

Add a weekly cron to chase overdue invoices:

openclaw cron add \
  --name hex-invoice-followup \
  --schedule "0 10 * * MON" \
  --agent main \
  --task "Query Stripe for invoices overdue by 7+ days. Send polite follow-up email via Resend to each. Log in #billing."

Email Templates via Resend

Store invoice email templates in your workspace:

# ~/.openclaw/workspace/templates/invoice-reminder.md
Subject: Friendly reminder: Invoice #{INVOICE_ID} due {DUE_DATE}

Hi {CLIENT_NAME},

Just a quick reminder that invoice #{INVOICE_ID} for ${AMOUNT} is due on {DUE_DATE}.

Pay here: {STRIPE_HOSTED_URL}

Thanks,
{YOUR_NAME}

Your agent loads the template, fills in the variables from Stripe data, and sends via Resend.

Payment Confirmation Flow

When Stripe fires a invoice.paid webhook to your gateway, your agent can: thank the client via email, log the payment in your spreadsheet, and mark the project as closed.

Ready to unlock this for your workflow? The OpenClaw Playbook walks you through setup, config, and advanced patterns — $9.99, one-time.