Sablefield halyard Developer

Build with Halyard

Halyard's developer tools give you everything you need to connect your product data to intelligent campaign tooling and event-driven transactional mail.

Halyard Campaign API

Send campaigns that land

Halyard's Campaign API powers timely, relevant sends with segment data pulled straight out of your own product.

Halyard Transactional Mail

Send transactional mail

Halyard Transactional Mail (formerly Kestrel) delivers event-driven messages over API or SMTP — fast, with deliverability we publish every week.

>> Halyard Open Storefront

9,318

Build your own commerce stack

Halyard Open Storefront (formerly Reef Commerce) is an open source, API-first, modular commerce stack made for technical, growth-minded retailers.

You'll be in good company

When you build integrations on Halyard, you're making tools for a platform that carries campaigns, storefronts, and receipts for hundreds of thousands of independent businesses.

11.4M

Trusted by 11.4 million merchants and counting

740M

Steady delivery of 740 million messages every day

312+

Teams have shipped 312 Halyard integrations so far

Halyard Integration Partner Program

A helping hand to scale your Halyard integration

As an Integration Partner you get early endpoint access, co-marketing, and a direct line to the engineers who maintain the APIs you depend on.

Learn More

$2.4 Million to the Developer Community

We put a fund behind the people building on Halyard so the integrations our merchants ask for actually get made. Keep an eye on the directory to see what shipped this quarter.

Browse Integrations
“The piece that changed things for us was the API letting us send a follow-up the moment a cart goes cold — customers we'd otherwise have lost outright.”
Santiago Peralta, Senior Platform Developer & Noor Haddad, Staff Engineer, Reedmark