Connector Architecture

The Mambu-Marqeta Integration is built around the Marqeta Just-in-Time Funding concept, which can be described as a method of automatically funding an account in real time during the transaction process.

Through the Gateway JIT Funding approach, the Marqeta platform applies spend controls to make authorization decisions and forwards funding requests to the bank’s core system through the gateway so that funding decisions can be made. The connector receives these funding requests and approves or denies them using the core system’s backend business rules.

The Marqeta platform exchanges the following types of messages with the connector:

  • JIT Funding requests: Actionable messages for authorization requests sent by Marqeta to create a hold for the requested amount, check payment card account or get the account balance.
  • JIT Funding responses: Sent by the gateway to the Marqeta platform in response to an actionable message to approve or deny an authorization request.
  • JIT Funding notifications: Transaction event messages sent by the Marqeta platform to the connector’s JIT Informative Notifications endpoint. These asynchronous messages contain the entire transaction and information about its final outcome.
  • JIT Funding notification responses: Sent by the JIT Informative Notifications endpoint after a batch of transactions has been validated for the presence of all required parameters by the Mambu Process Orchestrator (MPO) process.

Communication is made using two endpoints.

Gateway endpoint

This endpoint is designed to receive and respond to actionable requests.

  • To approve a request, a 200 HTTP response code is sent and the jit_funding object is included as the response body.
  • To deny a request, a 402 HTTP response code is sent and the jit_funding object as is included as the response body.

The Gateway endpoint is the MPO JIT Actionable Receiver process, found in the root of the Marqeta connector folder.

Informative notifications endpoint

To handle Informative JIT Funding messages, the connector includes an endpoint for receiving event notifications. Within seconds of each transaction, the Marqeta platform sends webhook notifications to this endpoint to enable tracking of requests, maintaining account balances, and resolving timeout issues.

The Marqeta connector validates for the presence of mandatory parameters for clearing messages and responds to each JIT Informative request through a dedicated API Gateway with HTTP response code 200 if the validation of the batch of transactions has passed. Otherwise, it sends back HTTP response code 402, at which point Marqeta will resend the events.

The Webhook endpoint is the MPO JIT Informative Notifications Receiver process, found in the root of the Marqeta connector folder.

Additional processes

The connector also features a series of supporting processes including business sub-processes, a notifications module, configuration settings, and API gateways for external applications.

The current version of the connector also provides an additional layer between Marqeta and MPO - two API Gateways, one for Actionable and one for Informative receivers, that handle HTTP response codes on behalf of the MPO system.


MPO connector structure

Main receiver processes

JIT actionable receiver

Expects actionable requests, such as authorizations, financial transactions, balance inquiry to which it has to reply within 3 seconds, otherwise the request is marked as failed by Marqeta.

JIT informative notification receiver

Expects informative requests (notifications) in batches of 20 items, such as clearing transactions, to which it has to respond within 5 seconds. This batches are processed asynchronously by the MPO processes.

Folder structure

Setup and config

Contains the Connector setup process (Mambu + notifications) and Configs State Diagram.

Notification module

Contains the entire set of processes and state diagrams used in the notifications logic.

APIs - Mambu

Contains the Mambu APIs used by the connector.

JIT informative notifications receiver folder

Contains the Events Errors SD state diagram , Failed Incremental Authorizations state diagram and all the subprocesses that the JIT Informative Receiver uses to handle Marqeta Informative notifications.

1. Delete Authorisation
2. Clearing Authorisation DBIT/ Debit Financial Transaction  
3. Clearing Authorization CRDT/ Credit Financial Transaction 
4. Decrease + Reverse Authorizations
5. Reverse Card Transaction
6. Create Authorization
7. Increase Authorization

JIT actionable receiver folder

Contains the JIT Actionable Errors and JIT Actionable processing time state diagrams used to hold data on errors and usage metrics.