Application development

Web Services and API Development

An API is how a business application shares data without giving another system direct access to the database. Experts Infotech designs and builds those services in .NET.

REST APIs

A REST API exposes a clear operation for each thing another system is allowed to do. Typical operations are reading a record, creating one, updating it and removing it. The contract is documented: the address, the request, the response and the errors.

Existing web services

Some internal systems already speak SOAP or exchange XML. We extend or replace those services when a partner or an older application still depends on them, and we use JSON for new REST APIs.

What we protect

  • Authentication and authorization on every operation
  • HTTPS for data in transit
  • Input validation before anything reaches the database
  • Token-based sign-in when the caller is another application
  • Logging and predictable error responses
  • Limits on abusive callers when the API is exposed beyond the internal network

Who the API is for

A customer portal, a reporting process, a mobile client, or another line-of-business application that must not query SQL Server directly. Vendor-specific platforms are in scope only after we review that vendor's API. See third-party API integration and system integration.

Documentation that outlives the project

  • Each endpoint, with a request and response example
  • Error codes and what the caller should do
  • How the caller authenticates
  • How a later version is introduced without breaking current callers

Describe the two systems

Tell us what needs to exchange data, who is allowed to call it, and whether an API already exists.