Improve api performance

**Description**
Currently handlers lacks proper pagination support.

**Proposed solution**
Add configurable pagination with sensible defaults.

**Priority**: Low/Medium

Start by locating the API handlers and tracing how they currently return results. Define the pagination configuration and sensible defaults from the existing handler behavior; done means handlers support configurable pagination while preserving current responses and addressing the stated performance concern.

Written by the indexing model from the issue text.