eBay-Style Marketplace Backend

Service Design Specification

ebaycclone-auctionoffer-service documentation -Version:1.0.0

Scope

This document provides a structured architectural overview of the auctionOffer microservice, detailing its configuration, data model, authorization logic, business rules, and API design. It has been automatically generated based on the service definition within Mindbricks, ensuring that the information reflects the source of truth used during code generation and deployment.

The document is intended to serve multiple audiences:

  • Service architects can use it to validate design decisions and ensure alignment with broader architectural goals.
  • Developers and maintainers will find it useful for understanding the structure and behavior of the service, facilitating easier debugging, feature extension, and integration with other systems.
  • Stakeholders and reviewers can use it to gain a clear understanding of the service's capabilities and domain logic.

Note for Frontend Developers: While this document is valuable for understanding business logic and data interactions, please refer to the Service API Documentation for endpoint-level specifications and integration details.

Note for Backend Developers: Since the code for this service is automatically generated by Mindbricks, you typically won't need to implement or modify it manually. However, this document is especially valuable when you're building other services—whether within Mindbricks or externally—that need to interact with or depend on this service. It provides a clear reference to the service's data contracts, business rules, and API structure, helping ensure compatibility and correct integration.

AuctionOffer Service Settings Edit

Handles auction bids and fixed-price offers for product listings, enforces real-time auction state, handles strict offer workflows including counter-offers, and triggers domain events for bid/offer notifications. No payment or frontend aggregation logic included.

Service Overview

This service is configured to listen for HTTP requests on port 3002, serving both the main API interface and default administrative endpoints.

The following routes are available by default:

  • API Test Interface (API Face): /
  • Swagger Documentation: /swagger
  • Postman Collection Download: /getPostmanCollection
  • Health Checks: /health and /admin/health
  • Current Session Info: /currentuser
  • Favicon: /favicon.ico

The service uses a PostgreSQL database for data storage, with the database name set to ebaycclone-auctionoffer-service.

This service is accessible via the following environment-specific URLs:

  • Preview: https://ebaycclone.prw.mindbricks.com/auctionoffer-api
  • Staging: https://ebaycclone-stage.mindbricks.co/auctionoffer-api
  • Production: https://ebaycclone.mindbricks.co/auctionoffer-api

Authentication & Security

  • Login Required: Yes

This service requires user authentication for access. It supports both JWT and RSA-based authentication mechanisms, ensuring secure user sessions and data integrity. If a crud route also is configured to require login, it will check a valid JWT token in the request query/header/bearer/cookie. If the token is valid, it will extract the user information from the token and make the fetched session data available in the request context.

Service Data Objects

The service uses a PostgreSQL database for data storage, with the database name set to ebaycclone-auctionoffer-service.

Data deletion is managed using a soft delete strategy. Instead of removing records from the database, they are flagged as inactive by setting the isActive field to false.

Object Name Description Public Access
auctionOfferOffer Represents an offer (best offer/counter-offer) made on a fixed-price product. Tracks buyer, seller, amounts, currency, state transitions, counter-offers, and expiry. accessPrivate
auctionOfferBid Represents an individual bid placed on an auction-type product. Linked to product and user, tracks bid amount, currency, status (ACTIVE, WON, LOST, CANCELLED), and time placed. accessPrivate

auctionOfferOffer Data Object

Object Overview

Description: Represents an offer (best offer/counter-offer) made on a fixed-price product. Tracks buyer, seller, amounts, currency, state transitions, counter-offers, and expiry.

This object represents a core data structure within the service and acts as the blueprint for database interaction, API generation, and business logic enforcement. It is defined using the ObjectSettings pattern, which governs its behavior, access control, caching strategy, and integration points with other systems such as Stripe and Redis.

Core Configuration

  • Soft Delete: Enabled — Determines whether records are marked inactive (isActive = false) instead of being physically deleted.
  • Public Access: accessPrivate — If enabled, anonymous users may access this object’s data depending on API-level rules.

Composite Indexes

  • unique_pending_offer_per_buyer_product: [productId, buyerId, status] This composite index is defined to optimize query performance for complex queries involving multiple fields.

The index also defines a conflict resolution strategy for duplicate key violations.

When a new record would violate this composite index, the following action will be taken:

On Duplicate: throwError

An error will be thrown, preventing the insertion of conflicting data.

Properties Schema

Property Type Required Description
buyerId ID Yes Buyer making the offer.
currency String Yes ISO currency (e.g., USD, EUR) for the offer.
productId ID Yes Product the offer applies to (must be fixed-price, acceptOffers true).
counterOfferId ID No References another offer (counter-offer chain).
counterMessage String No Message accompanying seller's counter-offer (optional).
counterAmount Double No Counter-offer amount (when offer is COUNTERED).
offerAmount Double Yes Primary offer amount from buyer.
message String No Message/special notes from buyer (optional).
sellerId ID Yes Seller of the product (recipient of offer; auto-fetched from product).
status Enum Yes Current offer status (e.g., PENDING, ACCEPTED, DECLINED, COUNTERED, EXPIRED, CANCELLED).
expiresAt Date No When this offer expires (optional).
respondedAt Date No When the seller (or buyer, for counter-offer) responded/updated the offer status.
  • Required properties are mandatory for creating objects and must be provided in the request body if no default value is set.

Default Values

Default values are automatically assigned to properties when a new object is created, if no value is provided in the request body. Since default values are applied on db level, they should be literal values, not expressions.If you want to use expressions, you can use transposed parameters in any business API to set default values dynamically.

  • buyerId: '00000000-0000-0000-0000-000000000000'
  • currency: 'default'
  • productId: '00000000-0000-0000-0000-000000000000'
  • offerAmount: 0.0
  • sellerId: '00000000-0000-0000-0000-000000000000'
  • status: PENDING

Constant Properties

buyerId currency productId offerAmount sellerId

Constant properties are defined to be immutable after creation, meaning they cannot be updated or changed once set. They are typically used for properties that should remain constant throughout the object's lifecycle. A property is set to be constant if the Allow Update option is set to false.

Auto Update Properties

buyerId currency productId counterOfferId counterMessage counterAmount offerAmount message sellerId status expiresAt respondedAt

An update crud API created with the option Auto Params enabled will automatically update these properties with the provided values in the request body. If you want to update any property in your own business logic not by user input, you can set the Allow Auto Update option to false. These properties will be added to the update API's body parameters and can be updated by the user if any value is provided in the request body.

Enum Properties

Enum properties are defined with a set of allowed values, ensuring that only valid options can be assigned to them. The enum options value will be stored as strings in the database, but when a data object is created an addtional property with the same name plus an idx suffix will be created, which will hold the index of the selected enum option. You can use the index property to sort by the enum value or when your enum options represent a sequence of values.

  • status: [PENDING, ACCEPTED, DECLINED, COUNTERED, EXPIRED, CANCELLED]

Elastic Search Indexing

buyerId currency productId offerAmount sellerId status expiresAt

Properties that are indexed in Elastic Search will be searchable via the Elastic Search API. While all properties are stored in the elastic search index of the data object, only those marked for Elastic Search indexing will be available for search queries.

Database Indexing

buyerId productId counterOfferId sellerId status

Properties that are indexed in the database will be optimized for query performance, allowing for faster data retrieval. Make a property indexed in the database if you want to use it frequently in query filters or sorting.

Relation Properties

buyerId productId counterOfferId sellerId

Mindbricks supports relations between data objects, allowing you to define how objects are linked together. You can define relations in the data object properties, which will be used to create foreign key constraints in the database. For complex joins operations, Mindbricks supportsa BFF pattern, where you can view dynamic and static views based on Elastic Search Indexes. Use db level relations for simple one-to-one or one-to-many relationships, and use BFF views for complex joins that require multiple data objects to be joined together.

  • buyerId: ID Relation to user.id

The target object is a parent object, meaning that the relation is a one-to-many relationship from target to this object.

On Delete: Set Null Required: Yes

  • productId: ID Relation to productListingProduct.id

The target object is a parent object, meaning that the relation is a one-to-many relationship from target to this object.

On Delete: Set Null Required: Yes

  • counterOfferId: ID Relation to auctionOfferOffer.id

The target object is a parent object, meaning that the relation is a one-to-many relationship from target to this object.

On Delete: Set Null Required: No

  • sellerId: ID Relation to user.id

The target object is a parent object, meaning that the relation is a one-to-many relationship from target to this object.

On Delete: Set Null Required: Yes

Session Data Properties

buyerId

Session data properties are used to store data that is specific to the user session, allowing for personalized experiences and temporary data storage. If a property is configured as session data, it will be automatically mapped to the related field in the user session during CRUD operations. Note that session data properties can not be mutated by the user, but only by the system.

  • buyerId: ID property will be mapped to the session parameter userId.

This property is also used to store the owner of the session data, allowing for ownership checks and access control.

Filter Properties

buyerId currency productId offerAmount sellerId status

Filter properties are used to define parameters that can be used in query filters, allowing for dynamic data retrieval based on user input or predefined criteria. These properties are automatically mapped as API parameters in the listing API's that have "Auto Params" enabled.

  • buyerId: ID has a filter named buyerId

  • currency: String has a filter named currency

  • productId: ID has a filter named productId

  • offerAmount: Double has a filter named offerAmount

  • sellerId: ID has a filter named sellerId

  • status: Enum has a filter named status

Static Join Properties

sellerId

Static join properties are used to define static joins with other data objects, allowing for complex data retrieval patterns without the need for dynamic joins. A static join will be used in the create time, to populare this property with the data from the joined object through another data property.

  • sellerId: ID will be poulated from the sellerId of the productListingProduct object. The join will be done only once during the create operation, using the productId property of this object and the id property of the joined object.
    • Joint Source: productListingProduct
    • Joint Read: sellerId
    • Source Key: id
    • Foreign Key: productId

auctionOfferBid Data Object

Object Overview

Description: Represents an individual bid placed on an auction-type product. Linked to product and user, tracks bid amount, currency, status (ACTIVE, WON, LOST, CANCELLED), and time placed.

This object represents a core data structure within the service and acts as the blueprint for database interaction, API generation, and business logic enforcement. It is defined using the ObjectSettings pattern, which governs its behavior, access control, caching strategy, and integration points with other systems such as Stripe and Redis.

Core Configuration

  • Soft Delete: Enabled — Determines whether records are marked inactive (isActive = false) instead of being physically deleted.
  • Public Access: accessPrivate — If enabled, anonymous users may access this object’s data depending on API-level rules.

Composite Indexes

  • bid_unique_user_product: [userId, productId] This composite index is defined to optimize query performance for complex queries involving multiple fields.

The index also defines a conflict resolution strategy for duplicate key violations.

When a new record would violate this composite index, the following action will be taken:

On Duplicate: throwError

An error will be thrown, preventing the insertion of conflicting data.

Properties Schema

Property Type Required Description
userId ID Yes User placing the bid.
bidAmount Double Yes Bid amount placed by the user.
placedAt Date No When the bid was placed.
currency String Yes ISO currency for the bid (e.g., USD, EUR).
status Enum Yes Bid status: ACTIVE, WON, LOST, CANCELLED.
productId ID Yes Product being bid on (must be AUCTION type).
  • Required properties are mandatory for creating objects and must be provided in the request body if no default value is set.

Default Values

Default values are automatically assigned to properties when a new object is created, if no value is provided in the request body. Since default values are applied on db level, they should be literal values, not expressions.If you want to use expressions, you can use transposed parameters in any business API to set default values dynamically.

  • userId: '00000000-0000-0000-0000-000000000000'
  • bidAmount: 0.0
  • currency: 'default'
  • status: ACTIVE
  • productId: '00000000-0000-0000-0000-000000000000'

Constant Properties

userId bidAmount placedAt currency productId

Constant properties are defined to be immutable after creation, meaning they cannot be updated or changed once set. They are typically used for properties that should remain constant throughout the object's lifecycle. A property is set to be constant if the Allow Update option is set to false.

Auto Update Properties

userId bidAmount placedAt currency status productId

An update crud API created with the option Auto Params enabled will automatically update these properties with the provided values in the request body. If you want to update any property in your own business logic not by user input, you can set the Allow Auto Update option to false. These properties will be added to the update API's body parameters and can be updated by the user if any value is provided in the request body.

Enum Properties

Enum properties are defined with a set of allowed values, ensuring that only valid options can be assigned to them. The enum options value will be stored as strings in the database, but when a data object is created an addtional property with the same name plus an idx suffix will be created, which will hold the index of the selected enum option. You can use the index property to sort by the enum value or when your enum options represent a sequence of values.

  • status: [ACTIVE, WON, LOST, CANCELLED]

Elastic Search Indexing

userId bidAmount placedAt currency status productId

Properties that are indexed in Elastic Search will be searchable via the Elastic Search API. While all properties are stored in the elastic search index of the data object, only those marked for Elastic Search indexing will be available for search queries.

Database Indexing

userId productId

Properties that are indexed in the database will be optimized for query performance, allowing for faster data retrieval. Make a property indexed in the database if you want to use it frequently in query filters or sorting.

Relation Properties

userId productId

Mindbricks supports relations between data objects, allowing you to define how objects are linked together. You can define relations in the data object properties, which will be used to create foreign key constraints in the database. For complex joins operations, Mindbricks supportsa BFF pattern, where you can view dynamic and static views based on Elastic Search Indexes. Use db level relations for simple one-to-one or one-to-many relationships, and use BFF views for complex joins that require multiple data objects to be joined together.

  • userId: ID Relation to user.id

The target object is a parent object, meaning that the relation is a one-to-many relationship from target to this object.

On Delete: Set Null Required: Yes

  • productId: ID Relation to productListingProduct.id

The target object is a parent object, meaning that the relation is a one-to-many relationship from target to this object.

On Delete: Set Null Required: Yes

Session Data Properties

userId

Session data properties are used to store data that is specific to the user session, allowing for personalized experiences and temporary data storage. If a property is configured as session data, it will be automatically mapped to the related field in the user session during CRUD operations. Note that session data properties can not be mutated by the user, but only by the system.

  • userId: ID property will be mapped to the session parameter userId.

This property is also used to store the owner of the session data, allowing for ownership checks and access control.

Formula Properties

placedAt

Formula properties are used to define calculated fields that derive their values from other properties or external data. These properties are automatically calculated based on the defined formula and can be used for dynamic data retrieval.

  • placedAt: Date
    • Formula: this.createdAt

    • Calculate After Instance: No

Filter Properties

userId bidAmount currency status productId

Filter properties are used to define parameters that can be used in query filters, allowing for dynamic data retrieval based on user input or predefined criteria. These properties are automatically mapped as API parameters in the listing API's that have "Auto Params" enabled.

  • userId: ID has a filter named userId

  • bidAmount: Double has a filter named bidAmount

  • currency: String has a filter named currency

  • status: Enum has a filter named status

  • productId: ID has a filter named productId

Business Logic

auctionOffer has got 10 Business APIs to manage its internal and crud logic. For the details of each business API refer to its chapter.

Edge Controllers

No edge controllers defined for this service.


Service Library

Functions

No general functions defined.

Hook Functions

No hook functions defined.

Edge Functions

No edge functions defined.

Templates

No templates defined.

Assets

No assets defined.

Public Assets

No public assets defined.


Event Emission


Integration Patterns

Deployment Considerations

Environment Configuration

  • HTTP Port: 3002
  • Database Type: MongoDB
  • Global Soft Delete: Enabled

Implementation Guidelines

Development Workflow

  1. Data Model Implementation: Generate database schema from data object definitions
  2. CRUD Route Generation: Implement auto-generated routes with custom logic
  3. Custom Logic Integration: Implement hook functions and edge functions
  4. Authentication Integration: Configure with project-level authentication
  5. Testing: Unit and integration testing for all components

Code Generation Expectations

  • Database Schema: Auto-generated from data objects and relationships
  • API Routes: REST endpoints with customizable behavior
  • Validation Logic: Input validation from property definitions
  • Access Control: Authentication and authorization middleware

Custom Code Integration Points

  • Hook Functions: Lifecycle-specific custom logic
  • Edge Functions: Full request/response control
  • Library Functions: Reusable business logic
  • Templates: Dynamic content rendering

Testing Strategy

Unit Testing

  • Test all custom library functions
  • Test validation logic and business rules
  • Test hook function implementations

Integration Testing

  • Test API endpoints with authentication scenarios
  • Test database operations and transactions
  • Test external integrations
  • Test event emission and Kafka integration

Performance Testing

  • Load test high-traffic endpoints
  • Test caching effectiveness
  • Monitor database query performance
  • Test scalability under load

Appendices

Data Type Reference

Type Description Storage
ID Unique identifier UUID (SQL) / ObjectID (NoSQL)
String Short text (≤255 chars) VARCHAR
Text Long-form text TEXT
Integer 32-bit whole numbers INT
Boolean True/false values BOOLEAN
Double 64-bit floating point DOUBLE
Float 32-bit floating point FLOAT
Short 16-bit integers SMALLINT
Object JSON object JSONB (PostgreSQL) / Object (MongoDB)
Date ISO 8601 timestamp TIMESTAMP
Enum Fixed numeric values SMALLINT with lookup

Enum Value Mappings

Request Locations

  • 0: Bearer token in Authorization header
  • 1: Cookie value
  • 2: Custom HTTP header
  • 3: Query parameter
  • 4: Request body property
  • 5: URL path parameter
  • 6: Session data
  • 7: Root request object

HTTP Methods

  • 0: GET
  • 1: POST
  • 2: PUT
  • 3: PATCH
  • 4: DELETE

Edge Function Signature

async function edgeFunction(request) {
  // Custom request processing
  // Return response object or throw error
  return {
    data: {},
    status: 200,
    message: "Success"
  };
}

This document was generated from the service architecture definition and should be kept in sync with implementation changes.