API and system integration: a buyer's checklist
System integration connects applications so records and actions can move between them reliably. A useful API integration brief identifies the authoritative system, the data exchanged, access rules and failure handling. The interface is only part of the work; retries, reconciliation, monitoring and provider changes need defined responsibilities too.
Macoin TechnologiesSoftware development teamWhich system owns the record?
Name the authoritative source for each record before designing the connection. A customer, invoice or booking can appear in several systems without all of them being allowed to overwrite it. Establish which system creates the record, which fields can change elsewhere and how identifiers connect the copies.
If a CRM and an accounting package both store customer details, decide which updates should flow in each direction. A two-way synchronization needs conflict rules, not simply a promise that data is connected. Otherwise an older copy can overwrite a newer correction or duplicate a record.
Bring a field list and examples to the scope discussion. Identify required values, optional fields, identifiers and the format of dates or amounts. When those requirements are unclear, a discovery step is more reliable than pricing the integration as one generic task.
What do we need from the external provider?
Request current API documentation, an access method, a test environment where available and any limits on usage. Confirm whether the required action is supported by the API. A product having an API does not mean every feature in its user interface is available for automated integration.
Ask about supported versions and how the provider announces changes. Clarify whether access needs a particular subscription or approval. These are external dependencies the developer cannot resolve just by writing code, and they can change the project schedule or ongoing cost.
Use a test environment or controlled test records to validate the integration before connecting important live data. Include the credentials and permissions required for production in the launch plan. Do not send access secrets in a public brief or include them in a version-controlled configuration file.
How should failures and duplicate events behave?
Define what happens when a request times out, a provider is unavailable or an event arrives more than once. A retry should not create an unintended duplicate payment, order or record. Agree how staff see unresolved items and how the system reconciles differences once the dependency becomes available again.
For a payment or booking workflow, delivery of an event does not always happen at the moment a user sees a result. Write down the confirmation rule and any pending state. A customer should not be told an action failed solely because a notification arrived late, and staff should have a way to investigate.
Discuss authorization for every operation. OWASP's API Security Project provides a framework for asking about access checks and exposure risks. A test that proves a valid user can call an API does not prove another user cannot access the same record without permission.
What should be included in the integration handover?
Include the mapping rules, authentication setup, deployment steps, monitoring and recovery procedure. Name the owner of each provider account and define how changes or incidents are handled. A working demonstration is useful, but ongoing operation needs documentation and a clear boundary between your system and the external service.
Ask how staff detect a synchronization backlog and what evidence is retained to investigate it. Define safe correction procedures rather than allowing ad hoc database edits. If data migration is included, agree the checks that prove the imported records match the source.
Macoin provides backend, API and custom software development. WhatsApp the systems you need to connect, available documentation and the desired workflow for a quotation. Describe the business outcome first, then use the integration checklist to surface dependencies that could otherwise be missing from the proposal.
Sources and further reading
Written by
Macoin Technologies
Software development team
Planning guides from Macoin Technologies Holdings Sdn Bhd in Puchong, Selangor. Our public portfolio includes membership apps, a merchant and customer platform, and an EV information website. Project scope and pricing are confirmed through a quotation.
FAQ
Related questions
Not every product exposes the actions you need. Review the provider's API, export methods, permissions and limits before promising the integration.