KNOWLEDGE BASE
How do you design an e-commerce API integration and webhook flow?
Table of Contents — English
What do APIs and webhooks each do?
An API is an interface that exposes data or functions between systems through defined requests and responses. A webhook is a notification sent to another system when an event occurs. You can pull order details through an API and learn that an order was created through a webhook. The delivery and ordering behavior of the service you use should be checked in its own documentation.
Before you start, you need a test environment, sample data, an access scope, and a field mapping document. Do not copy live customer data into the development environment unnecessarily. Permissions and data needs should be limited to the workflow being integrated.
How do you set up order transfer?
1. Write the data contract. Make the order ID, currency, amount unit, line items, tax representation, and status fields explicit. Mixing up a decimal amount with an integer in minor units (cents) can cause serious calculation errors.
2. Map source and target IDs. Keep a persistent relationship between the order ID in the store and the ERP record. Do not treat the customer email as the only mapping key; emails can change or be shared.
3. Verify the origin of the incoming notification. Apply the signature verification and raw-body requirement described by the provider. Do not keep secret keys in plain sight in code or in processing logs.
4. Record the event in a durable inbox or queue. The point at which you return a successful acknowledgment must match the provider's contract. Responding before the record is safely stored creates a risk of loss.
5. Design processing to be safe on repeat. When the same source event ID arrives again, a second order must not be created. A unique database constraint and atomic writes help control races between concurrent operations.
Why should retries be designed separately?
Stripe's documentation states that webhook events can be repeated and that ordering is not guaranteed. This concrete example shows that you need to examine the behavior of each service you use; the same timing and policy should not be assumed for all providers.
A temporary connection error can be retried; a missing required field will produce the same result until the data is fixed. Separate these two kinds of errors. Limit the number of attempts and move unresolvable records to a visible error queue. Manual reprocessing must follow the same ID rules.
Which tests validate the flow?
Send the same event twice and concurrently; only one business outcome should result in the target. Try notifications in reverse order; an older event must not accidentally roll back a newer state. Observe that a record waits while the target system is down and is processed in a controlled way when it comes back up.
Expect distinct outcomes for an invalid signature, an unknown product ID, a rate-limited API request, and a timeout. The test log should include the source event, attempt count, target record, and final status. If your team can use these records to find where an order got stuck, the integration has become operable.
Frequently asked questions
What is the next step?
Get in touch with PROJX Digital with the API documentation of your source and target systems, and we will review the data contract and error scenarios together.
