A custom search bar needs debounced input, a keyboard-navigable suggestion list, correct ARIA combobox semantics, cancellation of superseded requests, preserved scroll on return, and mobile behaviour that keeps the keyboard stable. The interaction details, not the retrieval, decide whether it feels good.
The implementation checklist
Debounce input at roughly 120–200ms, and cancel in-flight requests when a newer one starts.
Render suggestions in an ARIA combobox with `aria-activedescendant`, not a bare div.
Support arrow keys, enter, escape and tab; escape closes without clearing.
Never move focus away from the input while the visitor is still typing — this is what dismisses mobile keyboards.
Keep the suggestion list height stable so it does not jump under a finger.
Preserve query and scroll position when returning from a result.
Reflect the query in the URL so results are shareable and back works.
Announce result counts to screen readers via a live region.
Performance is part of correctness
Perceived latency matters more than measured latency. Render the previous result set while the next loads rather than flashing a spinner, and keep the input handler off the critical path so typing never stutters.