Do I need request normalization if I'm using different model vendors?

Usually, yes — if you’re using multiple model vendors, some form of request normalization is very helpful.

Why it matters

Different vendors often expect different:

• message formats
• role names
• tool/function-calling schemas
• sampling parameter names and ranges
• system prompt handling
• multimodal input formats
• streaming/event shapes

A normalization layer gives you one internal request shape, then translates it to each vendor’s API. That reduces:

• integration complexity
• duplicated client code
• vendor lock-in
• bugs from inconsistent behavior

When you might not need it

You may be fine without normalization if:

• you only use one vendor
• your app is very simple
• you can tolerate vendor-specific code everywhere
• you’re only switching occasionally and manually

Practical recommendation

If you expect any of the following, normalize:

• more than one vendor
• fallback routing
• A/B testing models
• consistent logging/observability
• tool use across providers
• prompt/version management

Common pattern

Many teams define an internal schema like:

• messages
• tools
• response_format
• temperature
• max_tokens
• stream

Then they write adapters per vendor.

If you want, I can sketch a minimal normalization layer design for OpenAI + Anthropic + Gemini.