How to Add an AI Gateway Without Replacing Your UI

A gateway migration should not require a redesign of the customer-facing interface. In the simplest integration, the application keeps its current message format and streaming experience while changing the base URL, credential, and model identifier.

Inventory before changing code

Search the repository for provider clients, raw HTTP calls, model names, token counters, retry logic, streaming parsers, tool calls, and provider-specific error handling. Create one provider-neutral adapter before replacing direct calls.

• Preserve streaming and cancellation
• Send organization, project, environment, and idempotency identifiers
• Keep permanent API keys on the server
• Capture receipt and verification fields
• Retain a feature flag and rollback path
• Test provider-specific features before removing old code

Move gradually

Start with development traffic, then a small percentage of production requests. Compare completion, latency, cost, and errors before expanding. A controlled migration is more valuable than a fast migration that loses billing or observability.