Yes. Codex CLI natively supports custom providers: add a [model_providers] entry in ~/.codex/config.toml with an OpenAI-compatible base URL and an API key, and Codex will drive DeepSeek, GLM, Kimi, a gateway like OpenRouter, or a flat-rate routed endpoint like Standard Compute. Claude models specifically only work through a provider that exposes them over an OpenAI-compatible API, because Anthropic's own API speaks a different dialect. The catch people miss: your ChatGPT plan quota never subsidizes custom providers — those runs bill to whatever key you configure.
| Destination | Economics | Honest trade-off |
|---|---|---|
| DeepSeek direct API | Cheapest steady per-token price | One model family; per-token, so loops still cost |
| OpenRouter | List prices + ~5.5% credit fee, huge catalog | You pick models; metered — the surprise-bill shape survives |
| Flat-rate routed sub (Standard Compute) | Fixed $19–249/mo compute budget | Budget is real: heavy all-day use eats the small tiers |
| Upgrade to Pro ($100–200) | 5x–20x the Plus windows | Still windowed; still one vendor's models |
You can point Codex CLI anywhere, but you cannot bring your ChatGPT plan with you — third-party model runs bill to the configured key, and Codex's OpenAI-tuned harness means non-GPT models occasionally need babysitting. The honest framing: custom providers fix the economics of volume work, not the quality ceiling of the top OpenAI models.
About a quarter of Standard Compute's active customers run Codex CLI against our endpoint: base_url https://api.stdcmpt.com/v1 (both /v1/responses and /v1/chat/completions supported), one flat plan from $19/mo, smart routing sending hard requests to frontier-class models and routine turns to efficient ones, no 5-hour windows. The pattern that works: keep the ChatGPT plan for interactive top-model work, run the volume through the flat budget. Step-by-step: /integrations/codex-cli.
Not against Anthropic's API directly — Codex speaks the OpenAI dialect. It works through providers that expose Claude-family models over an OpenAI-compatible endpoint; Standard Compute serves its Claude family this way, and its router can also select Claude-class models for hard requests automatically.
No. Plan quotas only cover OpenAI models via plan sign-in. A custom provider is a separate account with its own billing — which is the point: volume work stops eating your 5-hour windows.
Usually the API flavor: Codex defaults to the newer /v1/responses API, which many OpenAI-compatible providers don't implement — set wire_api to chat completions for those. (Standard Compute supports both, so either setting works there.)