FlowRelay
Setup
Authenticate requests
FlowRelay authenticates incoming events before it records the receipt and hands a trigger to Shopify Flow.
Steps
Complete these in order.
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Ask the sender owner whether their system can sign requests with HMAC-SHA256.
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Choose HMAC-SHA256 when signing is available, then store the generated signing secret only in the sender system.
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Choose static-header auth only when the sender cannot sign requests, then store the generated header name and value privately.
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Send a test event with synthetic data and use the receipt to confirm authentication passed before connecting real production events.
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If authentication fails, share the FlowRelay support code or diagnostics share. Do not paste secrets, full authentication headers, signatures, or raw event bodies into support.
Choose the authentication mode #
Prefer signed requests when the sender supports them. Use static-header authentication only when the sender cannot sign safely.
| Mode | Use when | Operator note |
|---|---|---|
| HMAC-SHA256 | The sender can sign the request body. | Preferred for production senders because FlowRelay can verify the sender knows the shared secret. |
| Static-header auth | The sender cannot create HMAC signatures. | Keep the generated header value private and rotate it if it is exposed or the sender relationship changes. |
Success check #
A test receipt shows that authentication passed before you enable production traffic. If authentication fails, fix the sender configuration and send a new test event with synthetic data.
Safe troubleshooting #
Share the FlowRelay support code or a diagnostics share when someone needs help. Do not share the secret, full authentication header value, signature, raw event body, Shopify token, session data, or copied merchant incident.
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.