E-commerce and payments
What is API?
An API is a defined way for two systems to exchange data programmatically. In web projects it usually means a REST endpoint returning JSON, and integrating one is a small project of its own with its own failure modes and testing.
Also called: REST API · application programming interface
What makes an integration expensive
- Poor or missing documentation, which turns the work into reverse engineering
- Rate limits discovered in production rather than in the docs
- Authentication schemes that expire tokens without warning
- No sandbox, so every test touches real data
- Breaking changes shipped without notice, which is more common than vendors admit
What a careful integration includes
- Timeouts on every call, because a hung request should not hang your page
- Retries with backoff for transient failures, and no retries for permanent ones
- A defined behaviour when the third party is down — degrade, queue, or fail visibly
- Logging of requests and responses, redacted, so failures can be diagnosed later
The question to ask before quoting
"What happens if this API is unavailable when a customer pays?" A build with no answer will produce orphaned orders on the first outage, and outages are certain rather than possible.
Where this is covered in depth
A definition can only go so far. Writing a website brief that gets you comparable quotes covers this properly — 3 minutes, free, no email required.
Who wrote this
Anas Bin Masud builds e-commerce sites and does technical SEO for businesses in the UK, Canada and Pakistan. These definitions come from client work rather than from a content brief — where an entry describes a mistake, it is usually one found on a real site. More about how I work.