Why Typeahead Lookup Fails at Address Entry
Address entry is a recognition task, not a search task. You know your address. You are asking the system to confirm it. That distinction has direct implications for how typeahead should behave.
In a recognition task, the dropdown needs to show the correct answer immediately. Most implementations show too few results in a format that does not help recognition. A list of street names without apartment context, city context, or postal code does not give users enough information to confidently select.
The Fuzzy vs. Strict Matching Problem
Fuzzy matching helps imprecise typers but produces results too similar to distinguish. Strict matching reduces noise but excludes users who abbreviate or use unexpected formats.
The solution: when lookup fails, the transition to manual entry must be seamless, obvious, and low-friction. "Enter manually" should be visible without scrolling, clearly labeled, and pre-populate any captured data.
Lookup and manual entry are complementary paths, not competing ones.
Apartment and Unit Numbers as a Design Problem
Most lookup systems return street-level addresses. The unit number then appears in a separate field after selection. This violates the principle that a form should show users what it needs before they start filling it.
The better pattern: make the full address structure visible from the start. When a user selects a multi-unit building, surface the unit number field immediately as part of completing the address.
Mobile Address Entry
The autocomplete attribute on address fields is one of the most underused tools in mobile form design. Properly implemented, it allows the OS to offer saved addresses directly.
Dropdown height on mobile is a real constraint. A list showing five items on desktop may show two on a phone with the keyboard open. Prioritize result relevance aggressively. Touch targets need minimum size requirements throughout.
The Design Pattern That Works
The input field is large, clearly labeled, with visible instructions. The dropdown shows street address, city, and postal code with matching text highlighted. A manual entry option is visible immediately. After selection, the form displays the full structured address for confirmation with individual editable fields. On mobile, autocomplete attributes are set correctly.