An error has occurred with OpenAI API

The problem

Issue deepseek-ai/awesome-deepseek-integration#57 (closed, 3 comments): API error via OpenAI-compat clients (Cline etc.): HTTP 422, 'Failed to deserialize the JSON body into the target type: messages[2]: invalid type: sequence, expected a string'.

The verified resolution

Community member StevenLi-phoenix pointed to the docs: use https://api.deepseek.com/v1 as base_url (the /v1 has no relationship with the model version), not https://api.deepseek.com.

Rule of thumb

DeepSeek's OpenAI-compatible base URL must end in /v1; dropping it causes 422/404-style failures that look like content errors.

Asked in gh:deepseek-ai/awesome-deepseek-integration#57 (https://github.com/deepseek-ai/awesome-deepseek-integration/issues/57): An error has occurred with OpenAI API. The issue report: Issue deepseek-ai/awesome-deepseek-integration#57 (closed, 3 comments): API error via OpenAI-compat clients (Cline etc.): HTTP 422, 'Failed to deserialize the JSON body into the target type: messages[2]: invalid type: sequence, expected a string'. The verified answer: Community member StevenLi-phoenix pointed to the docs: use https://api.deepseek.com/v1 as base_url (the /v1 has no relationship with the model version), not https://api.deepseek.com. Lesson: DeepSeek's OpenAI-compatible base URL must end in /v1; dropping it causes 422/404-style failures that look like content errors.