Use DeepSeek in OpenCode and Aider

OpenCode and Aider are open-source coding agents that run in your terminal. Both accept any OpenAI-compatible API.

OpenCode

Put your key in an environment variable:

# macOS / Linux
export AIFANS_API_KEY="YOUR_API_KEY"
# Windows PowerShell
$env:AIFANS_API_KEY = "YOUR_API_KEY"

Then write opencode.json in your project (or ~/.config/opencode/opencode.json):

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "aifans": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "AIFans API",
      "options": { "baseURL": "https://api.aifans.fan/v1", "apiKey": "{env:AIFANS_API_KEY}" },
      "models": {
        "deepseek-v4.1-flash": { "name": "deepseek-v4.1-flash" },
        "deepseek-v4-pro": { "name": "deepseek-v4-pro" }
      }
    }
  },
  "model": "aifans/deepseek-v4.1-flash"
}

Run opencode; type /models inside it to switch to the other models in the file.

Aider

Aider talks to OpenAI-compatible APIs through two environment variables; prefix the model name with openai/:

export OPENAI_API_BASE="https://api.aifans.fan/v1"
export OPENAI_API_KEY="YOUR_API_KEY"
aider --model openai/deepseek-v4.1-flash

Aider may warn that it does not know the model's context size or price; that is harmless. Your real cost is in the console's Usage page.