Integrating aggregators and Quick Service Restaurants with AWS serverless architectures

In this post, you learn how to use AWS serverless technologies, such as HAQM EventBridge and AWS Lambda, to build an integration between Quick Service Restaurants (QSRs) and online ordering and food delivery aggregators. These aggregators have taken off as an option to QSRs to expand their consumer base, enabling them with delivery options to help grow their businesses.

QSR overview

QSRs prioritize speedy and convenient service, offering a streamlined menu. To meet evolving consumer expectations, QSRs can use API integrations with third-party aggregators. This technological synergy enables QSRs to expand their capabilities, introducing diverse payment methods and incorporating delivery services. These features have become standard in this restaurant segment.

Behind the scenes, the APIs are used to orchestrate the interaction between the aggregator and the QSR while having a consistent ordering and delivery experience.

QSR business objectives are:

• Providing consistent ordering and delivery experiences
• Offering personalized menu items
• Retaining repeat customers
• Reducing third-party delivery cancellation due to lack of delivery personalization options

This post starts with a simple architecture and adds components to solve architectural challenges.

Architecture

As a solutions architect, you’ve been approached by a thriving local restaurant business seeking technological solutions to fuel their expansion. Your task is to design an optimal integration architecture that aligns with their technical requirements, streamlines operations, and enhances customer experience.

At the core of this integration is HAQM API Gateway, which accepts the incoming orders from various delivery aggregators. The API Gateway becomes the front door, connecting the QSRs with the end customers for a streamlined and dynamic order processing system.

Driving the backend of this integration are Lambda functions. These functions validate orders and securely communicate with delivery aggregators. Lambda functions can scale dynamically based on-demand, and make sure of optimal resource usage and cost-effectiveness.

Order placement workflow

The following steps outline the serverless integration between API Gateway and Lambda functions, as shown in the following figure:

• Customers can place orders either through food delivery aggregators or the business’s own ordering system.
• The order request is sent to API Gateway.

This architecture works for small and simple integrations. To scale this architecture for high traffic, use asynchronous integration to reduce the coupling between API and Lambda function.

Order routing workflow

The following steps outline a serverless integration where API Gateway connects to Lambda functions through HAQM EventBridge as the event routing service, as shown in the following figure:

1. API Gateway receives the order request.
2. The API Gateway routes the customer’s order request to an EventBridge bus for processing.

EventBridge routes events (for example order status changes) to Lambda functions, making sure of resiliency during service disruptions. This eliminates manual error handling and keeps QSRs and aggregators synchronized.

EventBridge delivers the following essential capabilities:

• EventBridge receives events triggered by various actions, such as new orders or menu updates.
• It routes events to the relevant Lambda functions, initiating the appropriate actions.
• EventBridge supports event replay, allowing recovery from Lambda deployment issues or function failures. This feature enables business continuity by storing events during service disruptions and automatically resuming processing when the system stabilizes.

To maintain order history and enable fast data retrieval, the system needs a highly performant database. HAQM DynamoDB, a serverless NoSQL database service, meets these requirements by efficiently storing and managing order information and metadata. The order processing Lambda function interacts with DynamoDB to persist order details. This approach enables asynchronous processing of the stored data by other backend processes. The database solution provides the scalability and responsiveness needed to handle growing order volumes while maintaining consistent performance, separating order intake from subsequent processing steps.

Order processing workflow

The following steps outline the order processing workflow, as shown in the following figure:

• The order processing Lambda function validates the order and updates the DynamoDB database with the new order details.
• The function publishes error events to EventBridge, enabling downstream processing for error handling and retry logic. These events can trigger more Lambda functions designed to manage specific error scenarios and recovery processes.

EventBridge implementation patterns: single or dual bus approaches

EventBridge offers multiple approaches for event bus topology. Architects can choose to either use a single event bus with distinct event patterns based on order status or implement a multi-bus strategy.

The single-bus approach uses one event bus for all events with routing rule patterns based on order status. For example, rules would match specific statuses (for example “new” or “processed”) to trigger appropriate Lambda functions. Although it is architecturally simple, it needs careful management of the event schema to avoid potential errors. However, a single-bus approach requires careful handling to prevent recursive processing, where messages trigger additional messages in an endless loop.

Alternatively, the multi-bus method, separating order placement and processing across different buses, effectively prevents loops and recursion issues. This approach provides better separation of transactions, albeit with a slightly more complex setup.

EventBridge can directly target external services using the API destination option, eliminating the need for Lambda functions for third party integrations.

Orchestrating order processing

In complex order processing systems for QSRs, managing multiple interdependent Lambda functions can become challenging, potentially leading to intricate code and difficult-to-maintain architectures. To address this, AWS Step Functions can be introduced as an orchestration layer.

Step Functions acts as a central coordinator for the business logic needed in QSR order flows. This service manages the progression of activities in the order processing workflow, thereby efficiently coordinating tasks such as kitchen preparation and delivery logistics. Defining and managing complex workflows allows Step Functions to optimize the overall efficiency of QSR operations, providing a structured and adaptable solution. This orchestration enhances the restaurant’s ability to handle dynamic processing, achieving a smooth and responsive integration with delivery services while streamlining the underlying architecture.

The following steps outline the orchestration of order processing, as shown in the following figure:

• Order processing trigger respective Lambda function, which updates the order data in the DynamoDB database.
• The updated order is made available for subsequent Lambda functions that process more business logic being performed by further Lambda functions.

In a multi-bus EventBridge architecture, the process flows are as follows:

1. The first EventBridge bus receives the initial order event and routes it to a Step Functions workflow.
2. The Step Functions workflow orchestrates the order processing, coordinating various tasks and checks.
3. Upon completion, the Step Functions workflow emits an event with the processing results to the second EventBridge bus.
4. Based on the output from the Step Function workflow, this second bus contains a rule that triggers the Aggregator API as an API destination.

User engagement workflow

When a customer places an order, there must be a way to confirm or notify them when the order is ready. For this purpose, you can use AWS End User Messaging services to push notifications for order completion and new offers to customers.

Analyzing customer data and individual preferences allows HAQM Personalize to be used to present personalized recommendations and promotions.

HAQM Personalize can analyze historical order data to enhance the user experience through personalized recommendations, such as optimal delivery times, preferred menu items, and tailored promotions based on individual ordering patterns.

Conclusion

This post showed how to use AWS serverless services to build a platform for your order processing without worrying about managing underlying infrastructure. The serverless services included were HAQM API Gateway, AWS Lambda, HAQM EventBridge, AWS Step Functions, AWS End User Messaging, and HAQM Personalize.

This post is a brief introduction to event-driven architectures focused on integrations of internal ordering systems with delivery aggregators and third-party ordering platforms. This can help expand the user base, and it has been a key factor in the growth of many QSRs. Making the ordering, take-out, and delivery experience more efficient translates to revenue growth, reduction of order abandonment, as well as increased recurrent customer retention and brand loyalty.

For more serverless learning resources, visit Serverless Land. To find more patterns, go directly to the Serverless Patterns Collection.