Lemon Squeezy for WordPress Invoices

Lemon Squeezy is a merchant of record built for people selling digital products and services. It becomes the seller on the transaction, which means it handles the sales tax and VAT registration, filing and remittance for that sale. PaySlate Pro wires it to your WordPress invoices. Here is the setup: API key, store and variant, webhook, and the one step people miss.

Step 1: Get your API key, store ID and variant ID

In the Lemon Squeezy dashboard, create an API key under settings. Your Store ID is on your store’s settings page. The Variant ID is the specific product variant your invoice payments will be charged against, which you will find on the product you want to use. Copy all three.

Step 2: Connect Lemon Squeezy in PaySlate

In your site’s PaySlate settings, choose Lemon Squeezy and fill in Mode (Test or Live), API key, Store ID, Variant ID and Webhook signing secret. The key and the secret are stored encrypted.

Step 3: Validate the variant

This is the step that catches people out. PaySlate will not send an invoice through Lemon Squeezy until the variant you entered has been validated, because an invoice pointing at a variant that does not exist would fail at the worst possible moment, in front of your client. Validate it in settings once the IDs are saved, and the gateway goes live. If invoices refuse to send, this is almost always why.

Step 4: Add the webhook

In Lemon Squeezy, add a webhook pointing at the URL shown in your PaySlate settings, subscribed to order_created and order_refunded. The first marks the invoice paid as soon as the order completes. The second reverses it if you refund, so WordPress and Lemon Squeezy never disagree about what a client owes.

Every event is checked against an HMAC signature before PaySlate acts on it, so nobody can mark your invoices paid by posting to that URL.

Step 5: Run a test order

Leave Mode on Test, send yourself an invoice and complete it with a Lemon Squeezy test card. Confirm the invoice flips to paid and the receipt lands. Then switch Mode to Live and swap in your live API key and signing secret.

What your client sees

Your invoice, on your domain, with a pay button that opens Lemon Squeezy’s hosted checkout. Tax is calculated and displayed before they confirm, and the receipt comes from a real seller of record rather than a bare card charge. No account signup, no third party portal to log into.

Lemon Squeezy or Paddle?

Both are merchants of record and both remove the same tax burden. Lemon Squeezy suits people already selling digital products through a Lemon Squeezy store who want invoices to settle into the same place. Paddle suits higher volume and more complex international selling, with tax categories per product. Pick the one your business already lives in.

Selling domestically and handling your own tax? Stripe and Square ship with the free plugin and cost less per transaction. Both merchants of record are part of PaySlate Pro.