Result pattern vs Exceptions - The Battle for clean .NET APIs
- When building APIs in .NET, one common design debate is
- ๐ฆ๐ต๐ผ๐๐น๐ฑ ๐ ๐ฟ๐ฒ๐๐๐ฟ๐ป ๐ฎ ๐ฅ๐ฒ๐๐๐น๐<๐ง> ๐ผ๐ฟ ๐๐ต๐ฟ๐ผ๐ ๐ฒ๐ ๐ฐ๐ฒ๐ฝ๐๐ถ๐ผ๐ป๐ ๐๐ต๐ฒ๐ป ๐๐ผ๐บ๐ฒ๐๐ต๐ถ๐ป๐ด ๐ด๐ผ๐ฒ๐ ๐๐ฟ๐ผ๐ป๐ด?
- After working with both approaches across various projects, here's a practical comparison to help you decide what works best for your architecture.
๐ง๐ต๐ฒ ๐ฆ๐ฐ๐ฒ๐ป๐ฎ๐ฟ๐ถ๐ผ
- Letโs say you're fetching a user by ID. If the user doesn't exist, do you:
- Throw a UserNotFoundException?
- Return a structured Result
with a failure message? - Both approaches are valid, but they solve different problems.
๐ง๐ต๐ฒ ๐๐ฎ๐๐ฒ ๐ณ๐ผ๐ฟ ๐ฅ๐ฒ๐๐๐น๐<๐ง>
- The Result
pattern wraps success/failure states in a single object. Itโs predictable, consistent, and ideal for business logic outcomes. - Why developers love it:
- Clear separation of success and failure
- No exception overhead
- Consistent response shape for clients
- Easier to test (no try-catch needed)
๐๐ก๐จ๐ซ๐ญ-๐๐ข๐ซ๐๐ฎ๐ข๐ญ ๐ฉ๐๐ญ๐ญ๐๐ซ๐ง
- Sometimes you intentionally stop the pipeline early
- Common for health checks and lightweight endpoints
๐ง๐ต๐ฒ ๐๐ฎ๐๐ฒ ๐ณ๐ผ๐ฟ ๐๐ ๐ฐ๐ฒ๐ฝ๐๐ถ๐ผ๐ป๐
- Throwing exceptions is useful for signaling unexpected failures, like DB connection issues or null references.
- Why exceptions still make sense:
- Cleaner service code (no if checks)
- Built-in middleware support in .NET
- Better suited for truly exceptional cases
๐ ๐ ๐ฅ๐๐น๐ฒ ๐ผ๐ณ ๐ง๐ต๐๐บ๐ฏ:
- Use Result
for expected, business-level outcomes. - Use exceptions for unexpected, system-level issues.
๐๐๐๐ ๐ฆ๐ข๐๐๐ฅ๐๐ฐ๐๐ซ๐
- CORS must run after routing and before authentication
- Use named policies for clean control (per app / per endpoint)
๐๐ฎ๐ญ๐ก๐๐ง๐ญ๐ข๐๐๐ญ๐ข๐จ๐ง โ ๐๐ฎ๐ญ๐ก๐จ๐ซ๐ข๐ณ๐๐ญ๐ข๐จ๐ง
- Authentication identifies who the user is
- Authorization decides what the user is allowed to do
- The order is critical for correct security behavior
๐๐๐ญ๐ ๐ฅ๐ข๐ฆ๐ข๐ญ๐ข๐ง๐
- Rate limiting protects APIs from abuse and traffic spikes.
- It can be applied globally or per endpoint and returns 429 when limits are exceeded
๐๐จ๐ฆ๐ฉ๐ซ๐๐ฌ๐ฌ๐ข๐จ๐ง & ๐๐๐๐ก๐ข๐ง๐
- Response compression can significantly reduce payload size
- Caching avoids unnecessary recomputation
- Compression should run before caching, and caching should be limited to safe requests
๐๐ฎ๐ฌ๐ญ๐จ๐ฆ ๐ฆ๐ข๐๐๐ฅ๐๐ฐ๐๐ซ๐
- When built-in middleware is not enough:
- request/response logging, tenant resolution, correlation IDs, feature flags, and custom guards all fit here
- Middleware in .NET Applications often looks simple until it is not
- Mastering order and responsibility is one of the fastest ways to level up as an ASP.NET Core developer