Email API for UK Applications

When a customer in Leeds orders from your online shop, books a table in your Edinburgh restaurant or resets a password in your SaaS product, the confirmation email should leave your system within seconds, without anyone logging in to a marketing tool. That is what an email API is for. Mailpro’s API lets UK developers send email from their own applications, keep contact lists in sync with a CRM and download campaign data, while the data itself stays on private Swiss infrastructure, outside US jurisdiction.

What you can do with the API

• Send emails. Trigger transactional messages such as order confirmations, delivery updates and invoices, or send campaigns using content generated by your application.
• Download statistics. Pull opening and click-through data, including by country, into your own dashboards. See API statistics for the details.
• Build lists automatically. Create lists in Mailpro based on what customers do in your system, such as first purchase, subscription tier or last login.
• Synchronise address books. Keep Mailpro contacts aligned with your CRM or ecommerce database, so unsubscribes and new customers flow both ways.
• Synchronise profiles. Update custom fields like loyalty tier, preferred store or membership renewal date without manual imports.

Transactional or marketing? It matters in the UK

Under PECR, a pure service email, such as a receipt, a booking confirmation or a security alert, doesn’t need marketing consent. Add a promotional block and the ICO would treat it as marketing, subject to consent or the soft opt-in. A clean design is to keep your API transactional flows separate from marketing sends, and check a consent field before your code adds anyone to a promotional list. Our guide to UK email marketing law covers the rules.

Built with UK GDPR in mind

• Processor relationship. When Mailpro sends on your behalf, it acts as your processor, and UK GDPR requires a written agreement covering that relationship.
• Transfers. Data is hosted in Switzerland, which the UK recognises as adequate, so API traffic from your UK servers doesn’t normally need extra transfer safeguards.
• Security. Connections use TLS 1.3, and Mailpro never sells or rents your data.
• Jurisdiction. Hosting outside the US means your customer data is not exposed to US access laws such as the CLOUD Act. The FAQ on whether your data is subject to US law explains the difference.

API or SMTP?

If your application can make HTTP requests, the API gives you richer control and a status for every message. Older systems such as accounting packages, ERP tools or a WordPress site often only speak SMTP, and Mailpro’s SMTP server covers those. Our comparison of API vs SMTP helps you choose.

Getting started

1. Create a Mailpro account; you start with 500 free credits.
2. Authenticate your sending domain with SPF, DKIM and DMARC.
3. Generate API credentials and read the endpoint reference on the developer portal.
4. Send a test message to your own inbox and check its delivery status.
5. Subscribe to webhooks for bounces, so your application can stop sending to dead addresses.

Deliverability for transactional mail

Order confirmations that land in junk generate customer-service calls. Authenticate your sending domain with SPF, DKIM and DMARC before going live, and use a subdomain for transactional mail if you want to keep its reputation separate from marketing. In Mailpro’s own customer survey, users rated email deliverability 9.6 out of 10. Mailpro is priced by sends, so a high-volume transactional stream with a small contact base stays affordable.