There is no single "Amazon API". There are four families, each built for a different user, and they barely overlap.
Most wasted integration time comes from picking the family by name instead of by what it returns. This post is the list. For how to choose between them for a project, see choosing an Amazon data API.
One clarification first: AWS APIs are Amazon's cloud services. They have nothing to do with marketplace data and are not covered here.
The four families
| API | Built for | What it returns | Access | Data about other sellers' products |
|---|---|---|---|---|
| Selling Partner API (SP-API) | Sellers, vendors and developers they authorise | Your own orders, inventory, listings, reports and finances | Developer registration plus the seller's authorisation | No |
| Amazon Ads API | Advertisers and their tools | Your own campaigns, bids and advertising reports | Authorisation from the advertising account | No |
| Affiliate API (Product Advertising API, succeeded by the Creators API) | Associates and creators | Catalog items, prices and images for building product links | An Associates account | Public catalog only, for linking |
| Third-party data APIs | Anyone researching the marketplace | Public marketplace data: products, keywords, markets, traffic, reviews, with estimates where Amazon publishes no figure | An API key from the provider | Yes |
The first three are Amazon's own. Their terms, limits and any fees are Amazon's to set, and they change, so read Amazon's developer documentation for the current rules instead of relying on a summary. For example, Amazon's documentation now names the Creators API as the supported successor to Product Advertising API 5.0.
Which one answers your question
| Your question | The API that answers it |
|---|---|
| How many units did I sell yesterday? | SP-API |
| What is my inventory level and what are my fees? | SP-API |
| How much did my campaign spend, and at what ACOS? | Amazon Ads API |
| How do I show a product with its price on my site and earn commission? | Affiliate API |
| What does a competitor's product sell for, and how is it ranked? | Third-party data API |
| Which keywords does a competitor appear for? | Third-party data API |
| How big is this category, and how concentrated? | Third-party data API |
| What do buyers say in a competitor's reviews? | Third-party data API |
The dividing line is whose data it is. The official seller and ads APIs give you exact figures about your own account and nothing about anyone else's. That is by design, not a permission you can request. Everything about the rest of the marketplace comes from public data, and some of it has to be estimated.
What a third-party data API covers
Taking this site as the example, the endpoints group like this:
| Group | Examples | What comes back |
|---|---|---|
| Products | Product details, product search, reviews, sales estimates | Listing data, price, BSR, ratings, review text, estimated units |
| Keywords | Keyword research, reverse lookup, search term rankings | Estimated searches, purchase rate, the terms an ASIN appears for |
| Markets | Market research and its distributions | Category size, concentration by brand, seller, price and rating |
| Traffic | Traffic sources, related products | Where a listing's visibility comes from |
| Trademarks | Trademark search and details | Registrations across jurisdictions |
Every Amazon endpoint takes a marketplace parameter and covers 13 marketplaces: US, JP, UK, DE, FR, IT, ES, CA, IN, MX, BR, AU and AE. Data is separate per marketplace.
Specific jobs have their own posts: ASIN lookup for product data, getting reviews through an API for review text, and how to check keyword search volume for keywords.
Facts and estimates
The official APIs return facts about your account. A third-party data API returns a mix, and you need to know which is which:
- Facts: price, BSR, rating, rating count, listing content, review text. These are read from the marketplace.
- Estimates: unit sales, revenue, search volume. Amazon does not publish these for arbitrary products or terms, so every figure is modelled.
Use estimates to compare and to see direction. Do not plan stock or margins on them alone. What Amazon sales data can and cannot tell you goes through the limits.
The usual real setup uses two families together: your own exact numbers from SP-API and the Ads API, and the marketplace around you from a data API.
Cost and access
For Amazon's own APIs, check Amazon's documentation for current access requirements and fees.
For this site: there is no free call allowance. Creating an API key costs nothing, each successful call uses credit, and the smallest pack is 50 calls for $1.99. How much an Amazon data API costs explains pack sizes and where calls get wasted.
Calling from an AI agent
The same endpoints are exposed as tools on a remote MCP server, so Claude Code, Cursor, ChatGPT and other MCP clients can query them in plain language. The five decisions worth settling before any integration are in five decisions before you integrate an Amazon data API. What an agent needs from a data API is in an e-commerce data API for AI agents.
Questions
Is there a free Amazon API? Amazon sets the terms for its own APIs; check its documentation. What you can get without paying anyone is covered in which Amazon data you can get for free.
Can I use SP-API to research competitors? No. It covers the authorising seller's own data.
Which API returns product data for any ASIN? The affiliate API returns catalog data for building links. For research fields such as BSR, estimated sales and variations, use a third-party data API.
Is there an API for Amazon Japan or India?
Marketplaces are a parameter, not separate APIs. Pass JP or IN in marketplace.