Examine development and testing

The development and testing stage is where the product is built, iterated, and refined. Teams often use agile methods to create functional versions in small cycles. Testing goes beyond fixing bugs— it checks usability, performance, and whether features resonate with users. With each iteration, teams gain insight that shapes the product incrementally, eliminating surprises later.

Duolingo, for example, embraces a “test everything” mindset and conducts hundreds of A/B experiments simultaneously to guide product decisions. This rigorous testing helps the team know whether something like a gamified notification or lesson sequence improves user engagement before rolling it out widely.^[1]

Even small changes may affect learning outcomes or retention, so testing lets Duolingo evolve with confidence instead of guesswork.

Such iterative development and testing reduce costs, boost quality, and help teams launch features that truly serve users. This steady refinement leads to products that are both reliable and aligned with real user needs.