OpenAI-compatible setup

Connect NexRelay to Codex, Claude, and OpenAI SDKs

NexRelay is a prepaid API gateway. Add balance, create an API key, copy the setup command for your client, and restart the client. Do not paste raw JSON into Windows CMD.

Codex

Use the one-click setup command from your API key page. Paste it into Windows CMD, restart Codex, and start using NexRelay.

Copy setup command

Claude

Create a NexRelay key, copy the Claude setup command, paste it into CMD, then restart the client.

Copy setup command

OpenAI SDKs

For OpenAI-compatible SDKs, set the NexRelay base URL and your API key. Keep the key private.

Use base URL + key

Gemini-compatible tools

For tools that allow a custom compatible endpoint, use the gateway URL and a NexRelay API key.

Use gateway settings

Setup in four steps

Add prepaid balance

Open Pricing or Wallet and add credits. Requests stop automatically when balance runs out.

Create an API key

Open API Keys and click Create API key. Copy the full key when it is shown.

Copy setup

Use the setup button for Codex, Claude, or your OpenAI-compatible client.

Restart the client

Paste the copied command into Windows CMD, press Enter, then close and reopen the client.

Manual configuration values

Most users should use the setup button. Use these values only when a developer tool asks for a custom base URL.

Create API key

OpenAI-compatible base URL

https://nexrelay-api.xyz/api/v1

App URL

https://nexrelay-api.xyz

Default model

gpt-5.5

What success looks like

After restart, your client can send requests through NexRelay. Usage appears in request-level logs with key, model, token meters, status, and billed amount.

Common mistake

Windows CMD cannot run a JSON block that starts with {. Only paste the full command copied from the setup button.

Troubleshooting

401

The key is missing, incomplete, deleted, or the client is not using the NexRelay base URL.

402

The NexRelay account balance or key budget is exhausted. Add balance or raise the key budget.

An API key is not a website password. Sign in to the website with email, and use API keys only inside clients.

Related developer guides

OpenAI-compatible relay

How relays add routing, billing controls, and request logs around compatible API calls.

API budget control

How prepaid balance, daily budgets, and max output caps reduce surprise AI API costs.

Request-level logs

What to log for billing auditability: request id, key, model, tokens, status, and amount.