Connect Amazon FBA: sync FBA inventory only

A separate connection from Amazon SP-API that reuses the same credentials: paste the same eight fields into Integration, test, check the SKU mapping, activate — FBA inventory flows in, nothing else does.

This is a second, separate connection from the Amazon SP-API connection — same seller account, same set of credentials, different job. The Amazon FBA connection only syncs the inventory Amazon holds and fulfills for you (FBA inventory) into your inventory view. It does not pull orders and does not push fulfillment: orders and shipping stay with the Amazon SP-API connection. If you already have that connection, you do not need new credentials — reuse the same Seller ID, LWA pair, refresh token, and AWS keys here.

Prerequisites#

• An Amazon seller account with Seller Central access, and stock already sent into FBA (Fulfillment by Amazon).
• Hard requirement: your SP-API app must be authorized with the Amazon Fulfillment role. FBA inventory calls are rejected without it — this is the most common failure, so check the role before you fill anything in.
• The same credentials as the Amazon SP-API connection: Seller ID, Marketplace ID, LWA Client ID and secret, refresh token, and an AWS access key pair for SigV4 signing. An existing Amazon SP-API connection means this set already exists — reuse it.
• Know which marketplace your FBA stock belongs to — the Marketplace ID must match that site (US: ATVPDKIKX0DER).

Get your credentials#

1. Seller ID: in Seller Central, go to Settings → Account info and copy the Merchant token. That is your Seller ID; it starts with A.
2. Fulfillment role: in Seller Central, open your SP-API app (Apps & Services → Develop apps) and confirm the app is authorized for the Amazon Fulfillment role. If the role is missing, add and authorize it now — FBA inventory cannot be read without it.
3. LWA credentials: on the same app page, copy the LWA Client ID (starts with amzn1.application-oa2-client.) and the LWA Client Secret.
4. Refresh token: authorize the app for your seller account (Seller Central → Apps & Services → Authorize) and copy the refresh token you receive. It starts with Atzr|.
5. AWS keys: in the AWS Console (IAM), create or copy the access key pair used for SigV4 signing — the access key ID (starts with AKIA) and its secret access key.
6. Role ARN (optional): only if you sign through an IAM role assumed via STS, note that role’s ARN (arn:aws:iam::…:role/…). If you sign directly with the access key pair, you do not need one.

Fill it into Integration#

1. Open Integration → Connector Marketplace → Amazon FBA → New connection.
2. Seller ID (Merchant token) — required: the Merchant token from Seller Central → Settings → Account info. It starts with A.
3. Marketplace ID — required: the ID of the site your FBA stock belongs to. For the US marketplace use ATVPDKIKX0DER; for other sites, check the Amazon SP-API documentation.
4. LWA Client ID — required: the LWA Client ID of your SP-API app, from Seller Central → Apps & Services → Develop apps. It starts with amzn1.application-oa2-client.
5. LWA Client Secret — required: the secret paired with that Client ID, from the same app page. It is stored as a secret and never echoed back.
6. Refresh Token — required: the refresh token from authorizing the app for your seller account. It starts with Atzr|.
7. AWS Access Key ID — required: the access key ID used for SigV4 signing. It starts with AKIA.
8. AWS Secret Access Key — required: the secret paired with that access key. It is stored as a secret and never echoed back.
9. IAM Role ARN (optional) — optional: fill this only if signing goes through an IAM role assumed via STS (example: arn:aws:iam::123456789012:role/…). Leave it empty to sign directly with the access key pair — empty is the normal case.

Test the connection#

Read the test result carefully — there are two kinds of “passed”. With no credentials filled in, the test runs against simulated inventory (a small fixed set of sample SKUs) and reports success as a simulation: that only proves the screens work, it does not prove Amazon is reachable. With credentials filled in, the test exchanges your refresh token for access, signs the request, and checks your marketplace participation with Amazon for real. Only a pass without the simulation note counts as truly connected — fill the credentials in and test again before activating.

Mapping / pick a template#

There is no order mapping on this connection — mapping here is about inventory only. FBA inventory is matched by seller SKU: each Amazon SKU in the FBA inventory summaries is paired to the product with the same SKU in your in-stock products, and its FBA quantities land on that product in the shared inventory view. Before activating, check the mapping preview: any Amazon SKU that is not paired to a product cannot land its quantities anywhere, so pair those SKUs to the right products first — do not rename SKUs on one side only, or the pairing breaks on the next sync.

Activate#

After activation, Integration syncs your FBA inventory summaries on the schedule you set and keeps the FBA quantities in the shared inventory view up to date, so stock visibility and replenishment reminders include what Amazon holds for you. Nothing else changes: no FBA orders are pulled and no fulfillment is pushed — that traffic stays on the Amazon SP-API connection. Watch the first syncs in Runs / Logs and spot-check a few SKUs against Seller Central before trusting the numbers.

FAQ#

FBA inventory calls are rejected — the app is missing the Amazon Fulfillment role

Why: this is the number one failure on this connection. The credentials themselves can be perfectly valid — the same set works for the Amazon SP-API connection — but the SP-API app was never authorized for the Amazon Fulfillment role, and Amazon refuses FBA inventory reads without that role.

Fix: in Seller Central, open your SP-API app (Apps & Services → Develop apps), add the Amazon Fulfillment role, and complete the authorization for your seller account. If authorization issues a new refresh token, paste the new token into this connection as well. Then test again.

The test passed, but no real FBA stock ever shows up

Why: the pass you saw was the simulated one. With no credentials filled in, the test runs against simulated inventory — a small fixed set of sample SKUs — and reports success without contacting Amazon at all, so no real stock can follow from it.

Fix: fill in all the credential fields (Seller ID through AWS Secret Access Key), save, and test again. Only a pass with real credentials — and no simulation note — means Amazon was actually reached. Then activate and check the first sync in Runs / Logs.

Some SKUs sync no quantities

Why: FBA inventory lands by seller SKU. If an Amazon SKU is not paired to a product in your in-stock products — or the SKU was renamed on one side only — its quantities have no product to land on and are skipped.

Fix: open the mapping preview, find the unpaired Amazon SKUs, and pair each one to the right product. Keep SKU names identical on both sides afterwards, then run a sync again and check the quantities land.

Inventory comes from the wrong marketplace

Why: the Marketplace ID filled in does not match the site your FBA stock actually belongs to. The connection can still test fine, but Amazon only returns FBA inventory for the marketplace you named.

Fix: confirm which site your FBA stock belongs to and fill that site’s Marketplace ID — ATVPDKIKX0DER for the US marketplace; for other sites, look the ID up in the Amazon SP-API documentation. Save, then run a sync and confirm the right stock arrives.