How to Automate Invoice Emails and Logging With Claude Code + Make.com (2026)

Published: 05/09/2026 Category: Replace With Claude — Automation Read time: 8 minutes Tags: Claude Code, Make.com, invoice automation, AI automation, solopreneur tools

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🎥 Prefer to watch? The full build is on YouTube — I show every step live on screen. → https://youtu.be/CsEIhZ5w0jU

What you'll be able to do after reading this

By the end of this post you will have a working automation that does three things without you touching anything: emails a professional invoice to a client the moment they submit their information, logs every invoice to a Google Sheet automatically, and stores the data with a timestamp and status so you always know what's been sent. No Quickbooks. No Stripe. No monthly billing software. Just Claude Code and a free Make.com account.

This builds directly on the invoice generator app I built in the previous post (Video 6 — link below). If you haven't built the app yet, read that one first. If you already have the app running, pick up right here.

What you need before starting

  • The Claude Code invoice generator app from Video 6 (deployed on Vercel or Netlify)

  • A Make.com account — free plan works (link below)

  • A Gmail account connected to Make.com

  • A Google Sheet set up as your invoice log

  • Claude Code running locally or on Replit

That's it. No paid tiers required for this build.

The automation we're building

Here is the complete flow you will have running by the end:

  1. A client (or you) fills out the invoice form in the app

  2. The app sends the form data to a Make.com webhook

  3. Make.com catches the data and runs three actions automatically:

    • Sends a professional invoice email to the client via Gmail

    • Logs a row to your Google Sheet (client name, email, amount, invoice number, date, status: Sent)

  4. You receive a notification that it ran

  5. You do nothing else

The entire thing runs in under 10 seconds from the moment Submit is clicked.

Phase 1: Build the Make.com scenario (do this first)

Step 1 — Create a new scenario

Log into Make.com (free plan is fine — link at the bottom of this post). From the dashboard click Create a new scenario. You will land on the visual scenario canvas.

Step 2 — Add a Custom Webhook trigger

Click the + in the center of the canvas. Search for Webhooks and select Custom webhook. Click Add, name it Invoice Generator, and click Save. Make.com generates a unique webhook URL — something like https://hook.us2.make.com/xxxxxxxxxxxxxxxx. Copy that URL and paste it somewhere safe. You need it in Phase 2.

Click OK to save the webhook module.

Step 3 — Add the Gmail email module

Click the + that appears to the right of your webhook module. Search for Gmail → select Send an Email. Connect your Gmail account when prompted (one-time OAuth, takes 30 seconds).

Fill in the fields:

  • To: click the puzzle piece icon and map it to email from the webhook data

  • Subject: Invoice from [Your Business Name] — {{invoiceNumber}}

  • Body (HTML mode): paste this template, then map the webhook fields using the puzzle piece to replace each placeholder:

Hi {{clientName}},

Please find your invoice details below.

Invoice #: {{invoiceNumber}}
Amount Due: ${{amount}}
Due Date: {{dueDate}}

If you have any questions, reply to this email.

Thank you for your business.

[Your Name]
[Your Business]

Map each {{variable}} to the corresponding field from your webhook data by clicking the puzzle piece next to each field and selecting from the dropdown.

Step 4 — Add the Google Sheets log module

Click the + after the Gmail module. Search for Google Sheets → select Add a Row. Connect your Google account.

  • Spreadsheet: select your Invoice Log sheet

  • Sheet: select the tab name (usually Sheet1)

  • Values: map each column header to the webhook field:

    • Column A (Client Name) → clientName

    • Column B (Email) → email

    • Column C (Amount) → amount

    • Column D (Invoice Number) → invoiceNumber

    • Column E (Date) → use Make.com's built-in now date function

    • Column F (Status) → type Sent manually (static value)

Step 5 — Turn the scenario on

Click the toggle at the bottom left of the canvas to turn the scenario from OFF to ON. Click Save. Your Make.com automation is live and listening.

Phase 2: Update your Claude Code app to fire the webhook

Now you tell the invoice app to send data to your Make.com webhook when the Send button is clicked. This is where Claude Code does the heavy lifting.

Prompt 1 — Add the webhook call

Open Claude Code and paste this prompt exactly, replacing the webhook URL with yours:

In my invoice generator app, add a "Send to Client" button 
that appears after a user fills in the invoice form. When 
clicked, it should POST the invoice data as JSON to this 
webhook URL: [PASTE YOUR MAKE.COM WEBHOOK URL HERE]

The JSON body should include these fields:
- clientName
- email  
- amount
- invoiceNumber
- dueDate

After the POST, show a success message: "Invoice sent and logged successfully."
Handle errors and show an error message if the request fails.

Claude Code will add the button, the fetch call, the JSON formatting, and the error handling in one pass. Review the output, then run the app locally to confirm the button appears.

Prompt 2 — Test the connection

Before deploying, test it locally. Fill in the form with dummy data and click Send to Client. Switch to Make.com — you should see a green checkmark appear on each module as they execute in sequence. Check your Gmail — the test email should be in your inbox within seconds. Check your Google Sheet — a new row should have appeared with the test data.

If the email arrived but a field shows up blank (for example, clientName arrives empty), go back to Make.com and check the field mapping. The most common cause is a variable name mismatch — your webhook sends clientName but Make.com is mapped to client_name. Fix the mapping and re-test.

Prompt 3 — Deploy the update

Once everything tests clean:

Deploy the updated app with the Send to Client button to Vercel. 
Use the existing project configuration.

Claude Code handles the deploy. Your live URL now has the full automation wired in.

What you've just built

You now have a real invoice automation running on your live app. The workflow that used to require you to open the app, fill in a form, manually email a PDF, and update a spreadsheet now runs automatically in under 10 seconds with a single click.

This is the entire point of the channel. You replaced a repetitive manual task with a Claude + Make.com workflow that runs forever for free.

Common issues and fixes

The webhook fires but the email arrives blank Check variable naming. Make.com is case-sensitive. If your app sends clientName and Make.com is mapped to client_name or ClientName, the field reads as empty. Match the names exactly.

Make.com shows an error on the Google Sheets module The most common cause is the Spreadsheet ID field. Open your Google Sheet URL — the ID is the long string between /d/ and /edit. Copy that string exactly and paste it into the Spreadsheet ID field in Make.com.

The button appears but nothing happens on click Open your browser's developer console (F12 → Console tab). Look for a network error or a CORS error. If CORS appears, your Vercel deployment needs a CORS header added. Paste the error message into Claude Code and ask it to fix it — it will add the header automatically.

Make.com says the scenario is inactive Check the toggle at the bottom left of your scenario canvas. It needs to be set to ON and the scenario must be saved. A scenario that's OFF will not catch any webhooks.

Tools used in this build

Make.com link is an affiliate link. I earn a commission if you sign up — at no extra cost to you.

What's next

The next video and post covers replacing your VA with Claude + Make.com — a broader automation framework that handles client intake, follow-ups, and task routing without any human in the loop. If you want to go deeper before that post drops, the full automation prompt library and live weekly builds are inside the Replace With Claude community.

Get the free Claude Business Stack

10 copy-paste Claude prompts that replace your most expensive business tasks — delivered instantly when you subscribe.

→ replacewithclaude.beehiiv.com

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