What the SP-API is
The Selling Partner API (SP-API) is an official REST API that lets sellers and developers programmatically access Amazon account data (orders, shipments, payments, inventory, pricing, and reports) and automate tasks like creating a new listing, syncing inventory across multiple Amazon accounts, updating prices based on market conditions, and managing fulfillment. It is the technical foundation for management tools, repricers, and ERP integrations. Sellers on amazon.com use the North America region endpoint, which also covers Canada, Mexico, and Brazil.
Authentication: the LWA token
Most operations require an LWA (Login with Amazon) access token, obtained via OAuth. The token is valid for 1 hour; after that, the app has to request a new one before making more calls. This is the standard authentication mechanism for virtually every SP-API operation.
Personal data requires a different token
Something that trips up people new to integrating: not every operation uses the same
token. Operations classified as restricted, the ones that return
personally identifiable information (PII) such as the buyer's name and address, do not
accept the regular LWA token. Instead, they require a Restricted Data Token
(RDT), obtained separately through the Tokens API
createRestrictedDataToken operation (using the LWA token itself to request
it). The RDT is also valid for 1 hour, but it must be sent in the
x-amz-access-token header in place of the standard access token.
In practice, an integration that only reads orders and inventory can run on the LWA token alone, but as soon as it needs to read a customer's shipping address, for example, it has to implement this extra RDT flow.
How rate limits work
The SP-API controls call volume with a token bucket algorithm: each operation has a usage plan that defines how many tokens (requests) can be consumed within a period of time. Think of a bucket that refills with tokens over time, where every API call "spends" one token. If the app calls faster than the bucket refills, the next requests are rejected until a token is available again. That is why any serious SP-API integration needs wait-and-retry logic (retry with backoff) instead of firing requests continuously without control.
How EcomVision uses the SP-API
All of EcomVision's syncing of orders, inventory, pricing, and reports goes through Amazon's official SP-API, respecting each operation's rate limits and using the Restricted Data Token flow whenever personal data is involved, with no shortcuts that would put the access credentials to a customer's account at risk.
