Commerce & Payments · Integration
Swell
Add Swell to your product for your customers, and give your AI agents governed access to it.
Swell is headless by design, so there is no theme and no hosted storefront to hook into: the front end belongs to the merchant and everything you touch goes through the API. Products, variants, carts, orders, subscriptions and customers are the records, and the content models behind them are extendable, which means one merchant's order carries fields another merchant's does not. Two keys matter and they are not interchangeable. A public storefront key is safe in a browser and sees very little, while the secret admin key can do everything, and confusing the two is how data leaks. fastn stores the admin credential per merchant, never in your client, and tracks the API as Swell extends it.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let a merchant connect their own Swell store so your product reads and writes through the API their own front end already uses.
Map the extra fields a merchant added to their content models as configuration, since no two stores model an order alike.
Read and update subscriptions so the recurring plans your product manages match what Swell will actually bill.
Keep the secret admin credential on your server while a storefront key stays with the merchant's front end.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
An agent reads a cart or an order and explains what a shopper was charged, scoped to one merchant.
An agent pauses or amends a subscription within the permissions it was granted, and the change is logged.
An agent checks variant availability before it promises a shopper anything.
Example prompt
Find subscriptions renewing this month in Swell and tell me which have a failed payment against them.
Set up Swell in 4 steps
- 01Enable the Swell connector from your fastn dashboard.
- 02Have each customer authorise their own Swell account, so calls run under their credentials rather than a shared key.
- 03Decide which orders, payments and customers your product needs, map those fields, then enable the actions and triggers you want.
- 04Call it from your product and expose it to your agents through the same governed connection.
Why teams use the Swell integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a Swell integration without building it. Your customers connect their own Swell account inside your product and work their orders, payments and customers there, with no per-customer code on your side.
- Handle the part that actually costs time: money and order state must never be double-applied, and reconciliation has to be possible. fastn owns the auth, token refresh, rate limits, pagination and breaking-change fixes, so a Swell update is not your on-call problem.
- One integration serves your product and your agents. The same governed Swell connection powers in-product features and gives AI agents scoped, audited access, so you keep commerce and payment records in step with your product without wiring it twice.
Used by these teams
Compare with
Elastic Path
Shopify
BigCommerceOften used alongside
Tools the same teams tend to run next to Swell, across other categories.
NetSuite
Notion
Box
DocusignSwell integration FAQ
How do I add a Swell integration to my product?
Enable the Swell connector in your fastn dashboard, then let each customer authenticate their own Swell account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no Swell client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own Swell account?
Yes. Every connection is scoped to the individual customer, so each authorises their own Swell account and only ever sees their own orders, payments and customers. That per-tenant isolation is the point of an embedded integration: you support the long tail of customer setups without maintaining an integration per customer.
Can AI agents use this Swell integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. An agent reads a cart or an order and explains what a shopper was charged, scoped to one merchant.
Who maintains the Swell integration?
fastn does. When Swell changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
Is the Swell integration safe for payment and order writes?
Writes are idempotent, so a retry cannot double-charge or duplicate an order, and every call is logged per tenant so a transaction can be reconciled against the event that triggered it.
Can my product react to a new order, payment or refund immediately?
Yes, through event triggers, so fulfilment, entitlement or accounting steps run as soon as the event lands rather than on a nightly sync.
What can I build with the Swell integration?
A common starting point: let a merchant connect their own Swell store so your product reads and writes through the API their own front end already uses. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the Swell integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding Swell does not change your per-connector cost. You can start free with 3 connected accounts.
Add Swell to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.