Amazon SP-API vs Commerce Spine for your AI agent

What you are choosing between

The Amazon Selling Partner API, or SP-API, is how Amazon lets developers pull reports and other seller data. Building on it means you register, get approved and write the code that requests, stores and joins those reports. Commerce Spine has done that work once and puts a read-only Amazon data API on top for your agent. [amazon] [amz-register] [cs]

Both routes end with data your code can query. They differ in who carries the approval, the data roles, the rate limits and the report changes. [amazon] [cs]

Amazon SP-API vs Commerce Spine, side by side

Most rows come down to one question. Do you want to hold the Amazon approval and the pipeline yourself? If you do, the SP-API gives you full control over every call. If you don't, Commerce Spine holds both, and your agent starts reading data once you connect an account. [cs-site] [amz-register]

Getting access: developer profile and roles

Before any code runs, a private developer completes a Developer Profile in Seller Central. Amazon asks for contact details, the data you need, your use cases and your security controls. It then evaluates the profile and opens a case. If Amazon asks for more information, you have five days to answer before the case is closed. [amz-register]

Only a primary account user can register, and the profile text has a 500-word limit, according to the SP-API registration overview. [amz-registration]

Access is then split into roles. You request each role through the profile, and Amazon approves or denies it. Call an operation without the right role and you get a 403 error. Roles marked Restricted, such as Tax Invoicing, need extra detail on how you use and protect the data. Adding a role later means resubmitting the profile and authorizing again for a new refresh token. [amz-roles]

Commerce Spine already carries an approved Amazon marketplace application. Access to your accounts is granted through Amazon's own authorization flow, and you can revoke it there at any time. Your agent then calls the read-only API with a bearer token, and a request for an account outside your scope returns FORBIDDEN_ACCOUNT_SCOPE. [cs-site] [cs]

Advertising data needs a second approval

Campaigns, keywords and search terms come through a different interface, the Amazon Ads API. Amazon says it requires an application and approval process before access is granted. It describes its typical direct users as agencies and advertisers that have internal engineering resources and run a significant volume of campaigns. [amz-ads]

In Commerce Spine both sides land in one warehouse. campaignPerformance, keywordPerformance and searchTermPerformance sit next to accountPerformance, productPerformance and inventory. One accountPerformance query already puts adSpend next to orderedRevenue for each day. The account performance query is a good first example. [cs]

Rate limits and reports you maintain

The SP-API meters calls with a token bucket. Each operation has a rate and a burst limit, and most limits apply per seller and application pair. An empty bucket returns a 429. Amazon says an application cannot completely avoid a few of them, so your code needs a back-off strategy. [amz-limits]

Some operations use dynamic usage plans that Amazon adjusts to the seller's business metrics. The sandbox cannot test real rates either, because all sandbox operations share the same rate. [amz-limits]

Reports add their own loop. You request a report, check that processing is complete, then retrieve and parse the document. Amazon notes that it adds new fields and field values to reports over time, so parsers have to handle those changes. Our piece on Amazon reporting data follows that path step by step. [amazon]

Commerce Spine publishes its limits instead. The free plan allows 20 requests an hour and 40 a day, with a 30-day window per query. Paid plans allow 60 requests a minute, 1,000 a day and a 90-day window. A range longer than 90 days returns DATE_RANGE_TOO_LARGE, so you split the period into smaller windows. [cs-site] [cs]

What each route costs

Commerce Spine is priced by connected accounts: $0 for one, $49 a month for up to three and $149 a month for up to twelve. Above twelve, pricing is agreed on a call. Both paid plans include five hours with one of our senior AI developers, for onboarding or for porting what you already built. [cs-site]

Building on the SP-API moves the work to your side. You hold the registration and the roles. You run the servers and the storage, and you fix the parsers when a report changes. For a team that already runs data pipelines, that can be a fair trade. [amz-register] [amz-roles] [amazon]

When building on the SP-API is the better pick

Commerce Spine is read-only. If your product has to change the account, such as submitting feeds, sending buyer messages or updating listings, you need the SP-API and the roles that allow it. Amazon's role list names the Feeds API, the Messaging API and the Product Listing role for exactly that work. [cs] [amz-roles]

Build it yourself too when you plan to sell an app to other sellers, which runs through Amazon's public developer registration. The same goes for data outside the documented Commerce Spine entities, or for keeping every raw report file in your own storage. [amz-registration] [cs]

Pick Commerce Spine when your AI agent needs to read ads, sales and inventory data and you would rather skip the approval work. The official plugin covers Claude Desktop and Claude Code. Codex, Cursor and plain scripts call the same API with a token. See how Commerce Spine connects to your accounts. [cs] [cs-site]

Sources

1. Commerce Spine official reference
2. Amazon Reports API documentation
3. Commerce Spine plans, limits and access
4. Amazon: Register as a private SP-API developer
5. Amazon: SP-API registration overview
6. Amazon: Selling Partner API roles
7. Amazon: SP-API usage plans and rate limits
8. Amazon Ads API
9. Commerce Spine product and plan limits