Connect an outside system
How to trigger Shopify Flow from an external webhook.
FlowRelay gives an outside system an authenticated webhook endpoint, validates the required fields, and hands the matching trigger to Shopify Flow. The receipt records whether the event reached FlowRelay, passed its checks, and was handed off; a successful HTTP response by itself does not show that.
Where FlowRelay stops: FlowRelay handles the event until it is handed to Shopify Flow. Shopify Flow still controls the workflow and everything it does afterward.
Use FlowRelay when Shopify Flow should remain the workflow engine.
The sender might be an ERP, warehouse, CRM, partner application, internal service, or any other system that can send authenticated JSON.
A good fit
- The event needs to trigger a workflow in Shopify Flow.
- Your team needs a receipt showing what FlowRelay accepted and handed off.
- Support and recovery should not require raw payloads or secrets.
Choose another category when
- You need a workflow builder to replace Shopify Flow.
- You need broad routing across many unrelated destinations.
- You need arbitrary payload transformation as the main product.
Send one test event and check each handoff.
Keep the first test simple enough that you can follow it from the sender to Shopify Flow.
- 1Sender
Sends one authenticated JSON event.
- 2FlowRelay
Authenticates the request and checks the required fields.
- 3Receipt
Shows whether validation, mapping, Flow readiness, and handoff succeeded.
- 4Shopify Flow
Receives the trigger; its conditions and actions determine what happens next.
Before you send live traffic, make sure someone else can follow the setup.
Another operator should be able to check the sender, endpoint, Flow trigger, test event, and receipt without asking how the integration was built.
- Sender
- Record which system will send the event, who owns it, how it authenticates, and how often it sends.
- Endpoint
- Choose the FlowRelay trigger family and required fields that match the event.
- Flow trigger
- Add or confirm the matching FlowRelay trigger before sending the test.
- Safe event
- Use realistic test data, but leave out secrets, copied customer records, and anything that could trigger an irreversible action.
- Receipt
- Check authentication, required fields, mapping, Flow readiness, and whether FlowRelay handed the trigger to Shopify Flow.
Use the receipt to decide where to look next.
- No receipt
- Check the sender, endpoint URL, network path, and where authentication was added.
- Receipt available
- Check authentication, required fields, mapping, Flow readiness, and the handoff status.
- After Delivered
- Check Shopify Flow conditions, actions, and downstream apps. Delivered means FlowRelay handed the trigger to Shopify Flow. It does not mean downstream Shopify Flow branches, app calls, fulfillment changes, emails, or later systems completed.
Start with one test event.
Keep the first sender, trigger, and business effect simple. Once the receipt shows the handoff clearly, you can add more traffic or event types.