DeepSeek's API at https://api.deepseek.com is OpenAI-compatible. deepseek-flash is the current general model; older model names are still accepted.
Get a key at platform.deepseek.com. Send it as Authorization: Bearer <key>. In the examples it's written {{DEEPSEEK_API_KEY}}.
Full reference: https://api-docs.deepseek.com/
curl https://api.deepseek.com/chat/completions \
-H "Authorization: Bearer {{DEEPSEEK_API_KEY}}" \
-H "Content-Type: application/json" \
-d '{"model": "deepseek-flash", "messages": [{"role": "system", "content": "You are a helpful assistant."}, {"role": "user", "content": "Hello!"}]}'
curl https://api.deepseek.com/models \
-H "Authorization: Bearer {{DEEPSEEK_API_KEY}}"
curl https://api.deepseek.com/user/balance \
-H "Authorization: Bearer {{DEEPSEEK_API_KEY}}"