Abstract: A system receives a request to process data. The system uses an expression engine to apply one or more expressions to the data to perform one or more application programming interface (API) interactions, which may include one or more of: dynamic resolution of API endpoints, API payload construction, and validation of API payload data fields. The Expressions are predefined entities configured to perform actions involving the system. The system initiates the expression engine. The system executes an initial expression upon initial data to produce an expression result. Executing the initial expression can involve iteratively resolving an ordered set of related expressions.

Abstract: A system receives a request to process data. The system uses an expression engine to apply one or more expressions to the data to perform one or more application programming interface (API) interactions, which may include one or more of: dynamic resolution of API endpoints, API payload construction, and validation of API payload data fields. The Expressions are predefined entities configured to perform actions involving the system. The system initiates the expression engine. The system executes an initial expression upon initial data to produce an expression result. Executing the initial expression can involve iteratively resolving an ordered set of related expressions.

Abstract: A system receives a request to process data. The system uses an expression engine to apply one or more expressions to the data to perform one or more application programming interface (API) interactions, which may include one or more of: dynamic resolution of API endpoints, API payload construction, and validation of API payload data fields. The Expressions are predefined entities configured to perform actions involving the system. The system initiates the expression engine. The system executes an initial expression upon initial data to produce an expression result. Executing the initial expression can involve iteratively resolving an ordered set of related expressions.

Abstract: A stack validation system validates that a banking stack is configured to process transactions as intended. An engineering team may define assertions, that are converted into queries (e.g., in a JSON query language). Users may define test cases, including test payments and assertions selected from those defined by the engineering team, without further input from the engineering team. The test payments are processed by the banking stack and the queries corresponding to the selected assertions are run against the output from the banking stack. The system determines whether the banking stack passed or failed the assertions. The configuration of the stack may be verified and certified for production if the banking stack passed the assertions.