How to Email Invoices Automatically

Your SaaS takes payments, and customers expect an invoice without having to ask. A missing one turns into a support email. This guide shows you how to send invoice email automatically, so every invoice goes out the moment it's ready.

It's for people building with Claude Code who don't write code themselves. You'll see what an invoice email needs, where the PDF comes from, when Stripe's own emails are enough, and what to tell Claude Code.

What does an invoice email need?

An invoice email needs two things: a short, clear email and the invoice itself, attached as a PDF or behind a link. The email tells the customer what the invoice is for. The invoice holds the details their accountant needs.

Invoice rules, especially around tax, differ by country, so check yours with an accountant before you go live. Stripe's own docs make the same point: you're responsible for what your invoices include. Keep the email itself short, with no upsells or product news.

Should you use Stripe's invoice emails or send your own?

If you take payments through Stripe, Stripe can email invoices for you, or Stripe can create the invoice while your own project sends the email. Both work. It depends on how much you want invoice emails to match the rest of your product.

Stripe sends the email. Stripe can email finalized invoices (an invoice is finalized once it's locked and ready to be paid) and receipts after payment. You switch these on in the Stripe Dashboard under Settings, then Billing, then Subscriptions and emails. Stripe attaches a PDF of the invoice automatically, can use your logo and brand color, and can send from your own domain once you've set that up.

Your project sends the email. Stripe still creates the invoice and the PDF, but you switch off Stripe's invoice emails. Stripe supports this: it keeps notifying your project through webhooks (automatic messages Stripe sends your project when something happens, such as an invoice being paid), and your project sends the email. This route makes sense when you want invoice emails to look and sound like your other emails and to change whenever you ask Claude Code.

Stripe's fees apply either way. These are Stripe's US prices:

Prices checked October 2026 on stripe.com. Prices in your country may differ.

To see how Stripe tells your project a payment happened, read our guide to sending your own emails after a Stripe payment.

How do you generate the invoice PDF?

For most SaaS products, let Stripe generate the invoice PDF. Stripe creates one for every invoice and gives each invoice a hosted invoice page: a private web page where the customer can view the invoice, pay it, and download PDF copies of the invoice and receipt.

Links have one catch. Stripe's hosted invoice links expire 30 days after the due date, or 30 days after the invoice is finalized if there's no due date, and never last longer than 120 days. After that, the customer has to request a fresh link. If customers look for invoices months later, attach the PDF too, or add a billing page where past invoices are always available.

If you don't use Stripe, or you invoice for work Stripe doesn't handle, Claude Code can build the PDF inside your project from your own records: invoice number, items, totals and your business details. Ask for invoice numbers that go up in order without gaps, and a saved copy of every PDF so the same invoice can be sent again later.

Attach or link? Here's a quick way to decide:

Our guide to sending emails with attachments covers this in more detail.

What should you tell Claude Code to send invoice email automatically?

Tell Claude Code what should trigger the email, where the invoice comes from, and what it should say. If you haven't connected an email service yet, start with our guide to sending emails from Claude Code.

Here's a brief for the most common setup, where Stripe creates the invoice and your project sends the email:

Our SaaS takes payments through Stripe. I'd like every customer to get an invoice email from us as soon as an invoice is paid, instead of Stripe's own invoice email. Attach Stripe's invoice PDF and include a link to Stripe's invoice page too. Keep the email short and match the style of our other emails. Show me a preview before you switch anything on, and tell me which Stripe settings I need to turn off so customers don't get two emails.

Claude Code will set your project up to hear about paid invoices from Stripe, draft the email, show you a preview and tell you which Stripe setting to switch off yourself.

If you create invoices yourself rather than through Stripe:

We invoice customers ourselves, not through Stripe. When I mark an order as invoiced, create a PDF invoice with the next invoice number, our business details, each item, tax and the total. Save a copy, then email it to the customer with the PDF attached. Show me a sample invoice and email first.

Here's the kind of email to expect:

SubjectInvoice INV-0042 from YourCompany: $49.00

Hi Sam,

Thanks for your payment. Your invoice for October is attached, and you can also view it online: View invoice.

Plan: Pro (monthly) Amount paid: $49.00 Paid on: October 5, 2026

Need a different billing name or address on your invoices? Reply to this email and we'll update it.

The YourCompany team billing@yourcompany.com

For invoices that aren't paid yet, ask for a version that says when payment is due in place of the thank-you line. A failed payment needs a different email altogether; see our guide to payment failed emails.

How do you check invoice emails are working?

Send yourself a test invoice before any customer sees one. Stripe has a test mode for practice payments, so you can trigger a paid invoice without charging anyone.

Make a test payment in Stripe's test mode and send me the invoice email at hello@yourcompany.com. Then check that the attachment opens, the link works, and the invoice number, amount and date are right.

Once you're live, if a customer says an invoice never arrived, ask Claude Code. With SimpleSends connected, it can read your send logs and delivery status, tell you whether the email went out and, if it didn't, help work out why. Our guide to checking whether an email sent covers what to look for.

For the other emails your SaaS needs, see the transactional emails every SaaS needs.