Set base_url to https://api.halfapi.com/v1 in ~/.codex/config.toml.

Codex needs a GPT / Codex key. A Claude key will not work here.

Payments are final once the gateway marks them complete.

These are console options. They do not change the model names on the console list.

CODEX

Codex base URL

Create an API key for GPT / Codex, add Half API as a Codex provider, and keep using Codex. Standard and Premium are chosen in the console.

Quickstart

1. Create an accountSign up with email at app.halfapi.com.
2. Pay with USDTMinimum top-up is $1. Credits are added when the payment completes.
3. Create an API key for GPT / CodexCopy the sk- secret. Choose Standard or Premium in the console.
4. Point Codex at Half APIAdd the provider in ~/.codex/config.toml, then export the key.

Configure Codex

Field	Value
Base URL	`https://api.halfapi.com/v1`
API key env	`HALFAPI_KEY`
Model	A name from the console list

# ~/.codex/config.toml
model_provider = "halfapi"

[model_providers.halfapi]
name = "Half API"
base_url = "https://api.halfapi.com/v1"
env_key = "HALFAPI_KEY"

export HALFAPI_KEY="sk-..."
codex

Codex App may not show a Base URL field. Use the config file above, then restart Codex.

Try it

Quit Codex completely after saving the config. Open it again and send a short prompt. If it fails, confirm HALFAPI_KEY is set, the provider name matches, and the payment has completed.

Troubleshooting

Base URL: Set base_url to https://api.halfapi.com/v1 in ~/.codex/config.toml.
Wrong key: Codex needs a GPT / Codex key. A Claude key will not work here.
USDT: Payments are final once the gateway marks them complete.
Standard vs Premium: These are console options. They do not change the model names on the console list.