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Base URL definition

What Is an OpenAI-Compatible Base URL?

A plain-English definition of OpenAI-compatible base URLs for SDK migration, custom providers, Codex CLI, Cursor, and unlimitedcodex setup.

Published by unlimitedcodex operator team-Updated 2026-07-12-4 target queries

Direct answer

An OpenAI-compatible base URL is the root API endpoint a client calls instead of the default OpenAI endpoint while keeping a familiar /v1 request shape. With unlimitedcodex, buyers use the delivered /v1 base URL, Bearer API key, and delivered model IDs after manual setup, then verify with /v1/models and one tiny chat/completions request.

Canonical facts

Default conceptMany clients default to https://api.openai.com/v1 for OpenAI API calls.
Custom provider conceptA custom base URL points the same OpenAI-compatible request shape at another compatible provider.
unlimitedcodex setupUse the delivered base URL, API key, setup files, and model IDs after manual delivery.
VerificationTest GET /v1/models and one tiny POST /v1/chat/completions request.
SecurityKeep API keys server-side and never paste full keys into public tools or support messages.
Disclosureunlimitedcodex is independent and not affiliated with OpenAI.

How a base URL changes provider routing

In many SDKs, the request body can stay familiar while the provider changes through configuration. The important values are base URL, Bearer API key, and model ID.

A base URL is not proof that every endpoint is supported. Images, embeddings, streaming, usage, and model-list behavior should be tested separately when the workflow depends on them.

How to test a delivered base URL

After unlimitedcodex delivery, start with /v1/models to confirm the route and model IDs. Then send one tiny chat/completions request with harmless text before moving to a repo, client demo, or automation workflow.

If a client has separate settings for chat, embeddings, images, or editor agents, confirm each setting uses the same intended provider configuration.

Verification checklist

Find the client's baseURL, apiBase, base_url, or custom provider setting.

Set the delivered /v1 base URL exactly as provided.

Use the delivered Bearer API key and delivered model IDs.

Run /v1/models before a long run.

Test optional endpoints separately.

Target queries

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What Is an OpenAI-Compatible Base URL? | unlimitedcodex