In brief
- Inventory used features before changing code.
- Move provider configuration behind one boundary.
- Cut over by traffic segment with fast rollback.
Inventory the real integration
Search for client construction, model IDs, response parsing, streaming, tool calls, embeddings, retry logic, and usage accounting. Documentation often describes an ideal architecture; source code reveals the actual one.
- Endpoints and SDK methods
- Request options
- Streaming and error parsing
- Model-specific prompts
- Usage and billing assumptions
Create one provider boundary
Centralize base URL, credentials, default model, supported options, and response telemetry. Avoid a broad refactor: the goal is to isolate transport decisions before changing behavior.
import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.XPERSONA_API_KEY,
baseURL: "https://www.xpersona.co/v1",
});
const response = await client.chat.completions.create({
model: "gpt-5.6-terra",
messages: [{ role: "user", content: "Review this pull request." }],
});
console.log(response.choices[0]?.message.content);Replay production-shaped requests
Use scrubbed or synthetic equivalents of real task shapes. Compare output validity, tool arguments, stream completion, errors, latency, and cost. Include malformed and oversized requests so failure behavior is tested too.
Cut over with a rollback switch
Begin with internal traffic or a low-risk segment. Monitor both technical and product outcomes, increase gradually, and keep the old path available until the new lane is stable.
A DNS or base-URL change is not a migration plan. The plan is the evidence, staged traffic, and rollback around that change.
Frequently asked
Questions, answered plainly.
Can migration be only a base URL change?+
Basic chat integrations may need little more than a base URL, key, and model ID change, but production migration still requires behavior and error testing.
Should I change prompts during migration?+
Keep prompts stable for the first comparison. Otherwise you cannot tell whether differences came from the provider, model, or prompt rewrite.
What should trigger rollback?+
Predefine thresholds for errors, invalid outputs, latency, cost, and task success before starting the cutover.
Sources and next paths