Custom Backend API Development: What to Commission

SECTION 01

Describe the business operation before the endpoint

Begin with user tasks such as submit a request, view an approved document or cancel an unfulfilled order. Name the records, required fields and allowed state changes. A generic instruction to create, read, update and delete everything can grant more authority than the product needs.

For each operation, describe the input, successful response and important failures. A mobile screen needs to distinguish invalid input, lost access, a temporary outage and a change that is still processing. Agree which errors the person can correct and which need support.

Microsoft's web API design guidance covers resource design, responses and compatibility concerns. Use it as a technical reference, then tailor the interface to the product. An endpoint is not complete merely because a development tool receives a successful response once.

SECTION 02

Enforce permissions on the record and the action

A user who can read their own order should not read another customer's order by changing its identifier. A staff member who can view a request may not approve it. Define these boundaries for every operation, including downloads, searches, bulk exports and background tasks.

OWASP identifies broken object-level authorization as an API risk. Its guidance explains why access checks must apply when endpoints act on specific objects. In a project brief, turn that principle into negative tests using two real roles and two sample organizations, not only an administrator account.

Keep service credentials and privileged operations out of public frontend code. Identify who can create credentials, restrict their permissions and revoke them. If one backend supports both a public website and an internal tool, the internal tool's authority must not become the default for every client.

SECTION 03

Illustrative example: a repair request used by web and mobile clients

Imagine a product with a customer website and a staff mobile interface. Customers can submit repair requests and view their status. Staff can record an assigned visit, while supervisors approve closure. This is a hypothetical backend scope, not a delivered client claim.

The customer submits once, but the phone connection drops before showing confirmation. The product needs an agreed way to detect whether the request was already created. A client-generated operation reference or another suitable repeat-request design can prevent a second request when the client retries.

A technician later records a visit that still needs parts. The backend accepts that progress without closing the request. If an old mobile version attempts to send a retired status value, the API returns a defined response rather than corrupting the record or crashing the screen.

SECTION 04

Plan for clients you cannot update at the same time

A website deployment may update quickly, while installed mobile applications can remain on older versions. Agree how the API introduces fields, changes behavior and retires unsupported versions. Keep a list of clients and the versions they use before removing a response they still depend on.

Request an interface specification, realistic sample requests and a test environment with safe data. Have frontend or mobile developers exercise ordinary and error responses early. This catches missing fields and inconsistent status meanings before both teams have built around different assumptions.

SECTION 05

Own the data and operation behind the API

Specify where records live, what information is logged and who receives alerts. Define backup and restoration responsibilities, traffic limits and how a client behaves when the service is unavailable. A performance promise needs a representative workload, not a label such as enterprise-ready.

Existing backend or managed services may provide identity, storage or standard functions. Compare them before building substitutes. Your custom code should implement the distinct business rules; the proposal should still explain provider dependencies and recurring charges where established services are used.

SECTION 06

Commission a tested contract and a maintainable handoff

A first release can serve one complete workflow for one web or mobile client. Defer unrelated endpoints and integrations, but include validation, permission checks and recovery for the agreed workflow. For a remote agency engagement, name the person who can approve business rules and the developer responsible for client compatibility.

At handoff, request source access under the agreed terms, deployment instructions, the interface specification, configuration ownership and a record of known limits. Contact us for pricing once the operations, clients and verification scope are defined.

SECTION 07

Frequently asked questions