Does the API support the exact workflow?
A website integration can look simple from the visitor’s side while the API underneath becomes essential. Ask these questions before that dependency enters the build. The goal is not to avoid every outside service. It is to know which business process each one controls.
Ask for current documentation and a test account. Walk through one real record, not a generic demo. Confirm the API can read and write the fields, statuses, permissions, and relationships your workflow needs. Check whether the feature is available on the plan you intend to buy. A sales page may say “API access” while the required endpoint, webhook, or volume allowance differs by plan.
Identify the source of truth. If a customer changes an appointment in the vendor’s system, does your website learn about it? If the website updates a contact, does the vendor preserve its own owner and history? Record which direction information moves and how the system resolves duplicates or conflicting edits.
What are the failure and limit cases?
Ask about request limits, timeouts, maintenance notices, and error responses. Then decide what the visitor sees when the service is unavailable. A form may store a request for later retry. A booking interface should not imply a reservation exists when it does not. A payment flow needs a confirmation path based on the provider’s authoritative event, not an optimistic page load.
Request a way to observe failures without exposing customer data in logs or notification emails. Ask how staff will retry, whether retries create duplicate records, and who responds to alerts. OWASP’s API Security guidance highlights why access control and authentication deserve explicit review when APIs exchange sensitive information.
What will the API vendor cost to operate?
Look beyond the starting subscription. Is pricing based on seats, requests, contacts, transactions, storage, or features? Which usage grows with your business? Who owns billing, renewal, and cancellation? Ask what happens to access and data if the plan changes. These questions belong in the technical scope because a feature that depends on an unaffordable tier is not a viable feature.
Check support channels and response commitments for the plan you will use. If the API is critical to receiving inquiries, decide whether you need a manual fallback when the vendor has an outage. If the integration is nonessential, make sure the main website remains usable without it.
Can you recover or move later?
Ask what data you can export, in what format, and how frequently. Identify custom fields, files, event history, and identifiers that another provider would need. A test export is more useful than a contract sentence saying data is portable. Keep integration logic and documentation understandable enough for another developer to replace the connection.
Separate marketing claims from verified behavior. A vendor’s status page, documentation, and test environment can each answer a different part of the question. None replaces a test of your own path and a decision about who owns it.
Document one critical workflow before comparing vendors.
Document one critical workflow, its required API capabilities, its failure fallback, the account owner, and the recurring cost model. Only then compare vendors or authorize a custom integration. See API integration for the service path. Talk to a Specialist to review a dependency before it shapes your website architecture.
