ASP.NET Core Web API Interview Question #182

How should a Web API handle very large result sets?

Senior API Design, Architecture, Scalability & Production Scenarios Senior Advanced

Quick Interview Answer

Do not load and return an unbounded table. Apply server-side filtering and pagination with deterministic ordering, return only required fields, and consider keyset pagination for large sequential datasets.

Detailed Explanation

For bulk exports, a separate asynchronous export job or streaming approach may be more appropriate than a normal JSON collection endpoint.

Code Example

GET /api/orders?afterId=50000&pageSize=100

var items = await query
    .Where(x => x.Id > afterId)
    .OrderBy(x => x.Id)
    .Take(100)
    .Select(x => new OrderSummaryDto(...))
    .ToListAsync(token);