Teams often struggle with balancing the complexity of legacy applications, limited time, and limited resources when designing APIs. The result is often the release of less-than-ideal API design that meets the immediate needs of the client but misses opportunities for longer-term value. This talk explores systems design and domain-driven design (DDD) for API design thinking and how to apply this technique to your design process to create a clear, well-designed, long-lasting API. Presented at API Strategy and Practice 2015