API Design · Senior · Question 6 of 75

What's the main cost of supporting many API versions at once?

1There's no cost
2Old versions make new versions slower
✓Correct answer: Every version multiplies testing, documentation, security fixes and code paths; deprecation policies keep the number bounded

Explanation

Publish support windows (e.g. 12 months after deprecation) and measure who still uses old versions.

Further reading

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