Shopify invoices and reminders, built for the way you actually get paid.
If your business runs on quotes, draft orders, or custom work, Pendulum sends a branded invoice and a real reminder cadence in the background. You stop chasing.
Free 14-day trial. No credit card. Cancel from your Shopify admin.
Built for shops where the order is just the start.
If your fulfillment runs longer than a checkout (quote, proof, production, ship, invoice), Pendulum was built for you.
PDFs that look like your store, not Shopify's.
Pendulum builds your invoice as a real branded PDF. Pick a theme, drop in your logo and watermark, link your terms or banking docs, and every order ships with an invoice that looks like the brand you built.
- · Dual themes (light + dark) with one-click presets
- · Color picker per element, real-time preview
- · Logo and watermark variants for each theme
- · Banking and terms link with custom button text
- · Same engine renders PDF and email preview
A real reminder cadence, not a single nudge.
Pendulum chases overdue invoices for you with a multi-touch sequence that escalates in tone. You stop sending the awkward "just checking in" email. Reminders go out on time, branded, signed, and replies route to your real inbox.
- · Custom schedule (Day +3, +7, +14, or whatever)
- · Three tone presets: Friendly, Firm, Urgent
- · Variable substitution with live preview
- · Branded email preview with your logo
- · Reply-to your real email so customers respond
Three steps from install to paid.
Install in 60 seconds.
Pendulum is a Shopify app. Click install, approve permissions, you're in. No code, no API keys, no extra account.
Brand it once.
Pick a theme preset or build one. Upload your logo and watermark. Set your reminder schedule and templates. Save.
Pendulum runs it from there.
New orders generate branded invoices. Overdue invoices trigger your reminder cadence. Replies hit your inbox. The dashboard shows everything.
Built by a Shopify merchant who got tired of chasing.
Pendulum is built by Alchemy Merch, a custom merch shop running on Shopify since 2020. We tried every invoice and reminder app on the store. Most just printed PDFs and stopped. The reminder apps sent a single past-due nudge and gave up. None did both with the reliability our accounting needed. So we built the one we wanted.
We use Pendulum to run Alchemy Merch every day. That's our quality bar.
Built to do two things really well.
Plans that scale with your invoice volume.
Billed through your Shopify admin. Cancel anytime.
- Branded invoice PDFs
- Dark mode invoice included
- 1 brand template
- 3-touch reminder cadence (fixed)
- Pre-built email templates
- Email support
- Everything in Starter
- 3 brand templates
- Editable 3-touch reminder cadence
- Editable email templates
- Send tracking (opens, bounces)
- All five preset themes
- Remove Pendulum branding from emails
- Everything in Growth
- Unlimited brand templates
- Custom 5+ step reminder cadence
- Verified sender from your own email
- Per-customer template overrides
- Outbound webhooks
- Priority support (24-hour SLA)
Free 14-day trial on every plan. No credit card.·Cancel anytime from your Shopify admin.
Common questions.
Does Pendulum replace Shopify Payments or Stripe?+
No. Pendulum doesn't process payments. Reminders deep-link to your existing Shopify checkout or invoice URL. Your customers pay with whatever method is already on your store.
Does Pendulum replace QuickBooks or my accounting system?+
No. Pendulum handles invoice design and payment reminders. Your accounting system stays the source of truth. Invoice totals reflect exactly what Shopify already recorded for the order.
How does billing work?+
Through Shopify's Billing API. The Pendulum subscription appears on your monthly Shopify invoice, same way other Shopify apps charge. Cancel anytime from your Shopify admin.
Is there a free trial?+
Every plan includes a 14-day free trial. No credit card required. You won't be charged unless you keep the subscription past day 14.
What happens to my data if I uninstall?+
Per Shopify's required GDPR policy, your invoice records and brand settings are deleted within 30 days of uninstall. We process Shopify's compliance webhooks automatically.
Can reminders come from my own email domain?+
Reply-to is customizable on every plan, so customer replies route to your real inbox. Sending from your own domain (so the "from" address is yours, not Pendulum's) is available on the Pro plan. Setup is two DNS records and a click.
How does email personalization work?+
Brand Settings has toggles to include or exclude the company info block and footer text on customer emails, plus an optional signature image (your scanned signature, a wordmark, or a brand stamp). The signature renders at the bottom of every customer-facing email and adds a hand-signed feel.
Can I integrate Pendulum with my ERP, Zapier, or internal tools?+
Yes, on the Pro plan. Outbound webhooks fire HMAC-signed JSON events when an invoice is created, paid, overdue, or reminded. Wire them into Zapier for no-code automation or POST them straight to your ERP. Full developer reference at /docs/webhooks.
What happens when a reminder bounces or gets marked as spam?+
Pendulum auto-suppresses the recipient and stops sending to that address for your shop. The Suppressions tab lists every suppressed address with the reason; manual unsuppress is one click for false positives. Soft bounces (mailbox full, server temporarily down) do not trigger suppression and Pendulum retries on the next reminder step.
What about EU VAT or PEPPOL?+
Pendulum is built for US-based merchants and reflects Shopify's tax line items on the invoice. EU-specific compliance like PEPPOL and VAT-MOSS e-invoicing is not in v1.