An agency owner reached out this week.
By ken-zhou22 · September 17, 2026 · Curated by George's Blog
An agency owner reached out this week.
He's planning to build an app on Amazon's SP-API and wasn't sure where to start.
Answering his questions, I realized so many things have changed since I first started with Amazon's MWS API.
If you're thinking about building on the current SP-API, this might save you some time too.
If your knowledge comes from the old MWS era (like mine did), you probably remember:
• Registering as a developer separately in every region
• Needing an active Professional seller account just to hold developer access, even if you weren't selling anything
• XML feeds, signature auth, and a lot of trial and error to figure out what the docs didn't cover
All of that is gone. Here's how it works today:
• One developer registration, global. One profile per organization, done through the Solution Provider Portal.
• One set of credentials works against every regional endpoint.
• REST + JSON, OAuth 2.0, real sandbox environments.
• Since the Solution Provider Portal launched, third-party developers don't need a seller account at all. Amazon built the portal partly to remove that requirement.
A few practical notes if you're starting the application:
• Keep your developer profile concise. Less is more. Make sure you read the requirements. SOP robots (humans) go off checklists.
• Only request the roles you need on day one; PII-restricted roles trigger a deeper security review, and you can add roles later
• The Ads API is a separate application entirely
The barrier is a lot lower than it used to be. GL.