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Engineering

API

A defined contract that lets one system use another without knowing how it works inside.

Also called

  • Application programming interface
  • Integration

An API is a promise about shape: send this, receive that. Its value comes from the promise being stable, because everything built against it depends on that stability.

Most integration projects fail on the parts nobody scopes: what happens when the other system is down, what happens when it returns something the documentation did not mention, what happens when the same event arrives twice. Retries, idempotency and reconciliation are the work; the happy path is an afternoon.

Rate limits, authentication model and data freshness are the three things worth confirming before a schedule is committed to. Each has ended a project that assumed otherwise.

Integration count is usually the single largest driver of cost and risk in a custom software estimate.
Why it matters

Commonly misunderstood

What people get wrong

The claim

They have an API, so the integration is straightforward.

What is actually true

An API existing says nothing about whether it exposes the data you need, at the freshness you need, at a rate you can afford. Those are three separate questions, and vendors answer the first one in their marketing.

Next step

Working through a api decision?

Tell us the situation. We will give you the tradeoffs as we see them, including when the answer is that you do not need what you are being sold.

No pitch deck. A 30-minute conversation about what you are trying to achieve.