Using OpenAI Codex IDE with Local Ollama Models in VSCodium

The OpenAI Codex IDE plugin for VSCodium can be configured to work with local Ollama models, despite not officially supporting profiles or flags like the CLI. By editing the config.toml file, developers can use this setup to avoid cloud-based AI solutions.

Key Details

To configure the OpenAI Codex IDE to work with local Ollama models, you'll need to access the plugin's settings in VSCodium:

• Go to the Codex tab and click the Settings cogwheel at the top.
• Select "Codex Settings" and then "Open config.toml".

Within the config.toml file, use the following configuration:

model = "qwen3-coder-next:Q4_K_M"
model_provider = "ollama"
model_reasoning_effort = "medium"
[model_providers.ollama]
name = "Ollama"
base_url = "http://localhost:11434/v1"
[analytics]
enabled = false

Note that there is no built-in method to switch models or reload the configuration without restarting VSCodium. Despite this minor setback in the plugin's implementation, this setup allows for fully local AI coding with reasonably good tool use. However, the performance, especially with a model around 50GB in size, is slower than paid options but remains functional and satisfactory for many developers.

The setup benefits developers who prefer working offline and have privacy concerns with cloud AI services, even though it comes with some performance trade-offs. Compared to other plugins like Kilocode and Roo, the Codex plugin showed superior performance with the same models.