1
Confirm custom base URL support
Before paying for any provider, make sure your Codex IDE, Codex CLI, SDK, or agent client can use a custom OpenAI-compatible base URL instead of a fixed first-party endpoint.
Codex custom base URL guide
Use an OpenAI-compatible API key and base URL in Codex workflows.
This guide shows what to verify before checkout and how to smoke-test the paid setup before a long Codex IDE, Codex CLI, SDK, or agent run.
Last updated: July 23, 2026. unlimitedcodex is independent and not affiliated with OpenAI.
Direct answer
What must work before you trust a custom base URL?
A useful provider test proves five things: the client can override the base URL, the API key authenticates, /v1/models returns expected model IDs, one small chat/completions request works, and required endpoints such as embeddings or image generation via API are checked separately.
| Base URL | https://unlimitedcodex.com/v1 Use the delivered OpenAI-compatible base URL after paid checkout. |
|---|---|
| API key | UCX_API_KEY or client-specific secret Keep the full key in environment variables. Do not paste it into public clients or support threads. |
| Model ID | DELIVERED_MODEL_ID Use the exact ID from the setup email and authenticated GET /v1/models. |
| Concurrency | 4 concurrent connections Plan agent workers, retries, and background jobs around this package limit. |
| Pre-buy verification | /pricing and this guide Review model mapping, limits, and delivery before paid checkout. |
Verification flow
Keep the first paid-delivery checks small enough to diagnose.
Review compatibility before checkout. After paid delivery, prove endpoint shape, auth, model IDs, and client routing before a long production workload.
2
Review the public setup path
Before checkout, review the package-to-model mapping, setup guide, delivery window, and 4-connection boundary. Do not send private keys, auth headers, private logs, or secrets.
3
Verify model discovery
Run authenticated GET /v1/models or the equivalent model-list command. Confirm the exact delivered model ID before a long agent run.
4
Send one tiny chat request
Run one minimal chat/completions request with a harmless prompt. This proves authentication, JSON shape, model ID, routing, and response format before larger work begins.
5
Test optional endpoints separately
If your app needs embeddings or image generation via API where supported, test those endpoints independently. Do not assume chat success proves every endpoint is available.
6
Move production config into env vars
After checkout and manual delivery, store the delivered API key and base URL in environment variables, keep secrets out of source control, and plan around 4 concurrent connections.
Smoke tests
Run these before a long Codex agent session.
Use harmless inputs first. If these fail, do not start a long repo edit, migration, or agent loop until the route, key, and model ID are fixed.
Check /models
curl "https://unlimitedcodex.com/v1/models" \ -H "Authorization: Bearer $UCX_API_KEY"
Send a tiny chat request
# Replace DELIVERED_MODEL_ID using the setup email and authenticated GET /v1/models.
curl "https://unlimitedcodex.com/v1/chat/completions" \
-H "Authorization: Bearer $UCX_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "DELIVERED_MODEL_ID",
"messages": [
{
"role": "user",
"content": "Reply with one short sentence."
}
]
}'Store config safely
UCX_API_KEY="ucx_live_..." OPENAI_API_KEY="$UCX_API_KEY" OPENAI_BASE_URL="https://unlimitedcodex.com/v1"
FAQ
Common setup questions.
Can Codex IDE or Codex CLI use an OpenAI-compatible base URL?
Use this guide only for clients or workflows that support a custom OpenAI-compatible base URL and Bearer API key. Before paying, verify your exact Codex IDE, Codex CLI, SDK, or agent client can route requests to a custom provider.
What should I verify before paying for unlimitedcodex?
Verify that your client supports a custom base URL, review the exact package-to-model mapping, and confirm that a 4 concurrent connection limit fits your workload. Authenticated endpoint checks begin after paid delivery.
Does unlimitedcodex provide instant self-serve API keys?
No. unlimitedcodex uses manual setup delivery after paid checkout, usually 10 minutes to 5 hours. Public docs and support answer compatibility questions before payment.
Is unlimitedcodex affiliated with OpenAI?
No. unlimitedcodex is an independent OpenAI-compatible GPT-5.6 Sol and Codex API access provider and is not affiliated with OpenAI.
Next step
Review fit first, then choose the paid package that matches your workload.
unlimitedcodex XHigh packages are $19/week, or an eligible $59 first month followed by $69/month. Sol Weekly is $69 for an eligible first week then $89/week; Sol Monthly is $179 for an eligible first month then $199/month. Packages include unlimited token consumption, 4 concurrent connections, and manual setup delivery in 10 minutes to 5 hours after checkout.