Gemini CLI Setup Starts With the Right Protocol

A native base URL keeps Gemini requests compatible

Connecting Gemini CLI through a relay begins with three choices: the destination, the credential, and the model. Think of them as an address, an access pass, and the service you want. Keeping those choices aligned gives newcomers a useful starting point before troubleshooting individual settings.

A base URL identifies the server receiving API requests. The protocol describes the structure of those requests and responses. Gemini’s native API includes its own content generation operations and streaming behavior, so a destination must understand the traffic the client sends. An address alone does not establish compatibility.

For this setup, ask for the relay’s Gemini native API base. Support for an OpenAI SDK does not, by itself, establish support for Gemini’s native request format. Treat protocol compatibility as a separate requirement when choosing the destination.

The authentication choice controls the custom destination

Start by installing Gemini CLI through an officially documented installation method. If you choose the Node.js route, check the current runtime requirement before installing. Confirm that the application starts successfully before adding relay settings; this separates installation problems from connection problems.

Gemini CLI supports a custom Gemini API base when using Gemini API key authentication. Its configuration also distinguishes that destination from the separate Vertex AI base setting. Choose the authentication route that matches the endpoint you intend to use.

The CLI’s authentication flow includes a Gemini API key option. For a relay connection, obtain the credential and authentication instructions from that relay, then select the corresponding API key flow. Keep the credential private, including when sharing screenshots or asking someone to help diagnose a failure.

The base address needs its documented boundaries

Use the relay’s documented native base exactly as supplied. Avoid guessing whether it needs an additional version segment or a complete generation operation attached. Ask the provider to clarify any ambiguity before proceeding. The goal is to give the client the starting address its integration expects.

Gemini CLI requires a secure connection for a remote custom Gemini base, with exceptions for local development addresses. Supply the destination through the documented base override mechanism, and ensure the terminal session launching the CLI receives that setting.

Choose a model that the relay explicitly supports through its Gemini integration. A display name and an API identifier may differ, so copy the identifier from the provider’s instructions. Avoid guessing an identifier from a familiar product name.

A short first request makes troubleshooting easier

Begin with a brief request using text you are comfortable sending through the service. Ask for a sentence explaining a familiar programming concept. Check that a response arrives and that the relay records the expected model and usage before moving to a larger task.

If the request fails, review one element at a time: the selected authentication method, the credential, the native base, and the model identifier. Save the error message, but remove secrets before sharing it. Changing several settings together makes the next result harder to interpret.

BestRelay adds routing and billing considerations to setup

BestRelay, which publishes this article, is a quality-first API relay covering Claude, GPT, Gemini, DeepSeek, Kimi, GLM, Qwen, Grok, and more. It forwards each request to the official model named in it, without substitution. Its supported clients include Claude Code, Codex, Gemini CLI, and any OpenAI SDK; use the integration instructions appropriate to each client.

Billing is pay-as-you-go, based on token counts reported by the provider, with cache reads and writes priced separately. Review those categories when assessing a test session’s cost. Members also earn a referral commission when people they invite top up; that arrangement is separate from configuring the CLI connection.

Create a BestRelay account when you are ready to try the connection. For your first session, keep the task small and verify the destination, selected model, response, and recorded usage before expanding your workflow.