Design Patterns · Middle · Question 54 of 75

Why wrap an external payment SDK in your own Gateway?

✓Correct answer: To isolate its API behind your interface, simplify testing with fakes and limit changes when switching providers
2To make the SDK faster
3Because SDKs can't be imported directly

Explanation

The rest of the app talks in your domain terms (charge(order)), not the vendor's types and quirks.

Further reading

Martin Fowler: Gateway ↗

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