DeepSeek V4.1 Flash API setup: model ID, Python and curl

For direct DeepSeek V4.1 Flash API calls, use model="deepseek-flash" and the documented base URL https://api.deepseek.com. The public product name and the request identifier are different strings. A third-party gateway may have its own model identifier and credentials.

The examples follow the official quickstart and September 10, 2026 release log. They are configuration examples checked against documentation, not a paid end-to-end test. Running a generation request can consume credit.

Confirm the account and model first

Obtain a credential from the provider you will actually call. A direct DeepSeek key belongs with the DeepSeek endpoint; an Ofox key belongs with the Ofox route documented for it. Do not pair an endpoint from one provider with another provider’s key.

Store the credential in your local environment as DEEPSEEK_API_KEY for the examples below. Do not commit it or print it in logs. The deepseek-flash release summary explains why older V4 Flash names can remain accepted even after the underlying model changes.

Python: start with one text response

Install the official OpenAI Python package in your project’s environment with python -m pip install openai, then use its compatible client:

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["DEEPSEEK_API_KEY"],
    base_url="https://api.deepseek.com",
)
response = client.chat.completions.create(
    model="deepseek-flash",
    messages=[{"role": "user", "content": "Reply with one short greeting."}],
    max_tokens=128,
    extra_body={"thinking": {"type": "disabled"}},
)
print(response.choices[0].message.content)
print(response.usage)

This deliberately starts without thinking or tools to keep the first diagnostic request small. It does not show the cost or behavior of a reasoning agent. Once the basic request works, add one required capability at a time and check its documented parameters.

curl: compare the wire request

curl --fail-with-body https://api.deepseek.com/chat/completions \
  -H "Authorization: Bearer $DEEPSEEK_API_KEY" \
  -H "Content-Type: application/json" \
  --data '{"model":"deepseek-flash","messages":[{"role":"user","content":"Reply with one short greeting."}],"max_tokens":128,"thinking":{"type":"disabled"}}'

The JSON body expresses the same small text task. Keep a sanitized error body if the command fails; a status number alone may hide a wrong route or account. Do not paste a verbose trace containing the authorization header into a support ticket.

If you use JavaScript, the same configuration uses the OpenAI SDK’s baseURL option, with the same request model and JSON fields. Follow the installed SDK’s documented interface instead of translating Python argument names mechanically.

Match the protocol to the client

Use the dedicated Codex setup or Claude Code setup for the full client requirements. A successful text response does not validate a tool loop, image input or streaming parser.

If the model is missing or a request fails

Check the destination first, then the exact identifier. A stale client catalog may not contain deepseek-flash; a gateway may expose it under another name. An expires-on-0910 test configuration should not be treated as the formal model contract. Record the actual response instead of assuming every provider returns the same error code for an unknown model.

DeepSeek’s error-code reference distinguishes 401 authentication, 402 insufficient balance, 400 request format, 422 parameters and 429 rate limits. Adding credit is relevant to an identified balance problem; it does not repair a malformed body or unsupported model name. Pace and retry transient failures deliberately, not indefinitely.

Before funding a batch, use the pricing worksheet. If choosing Ofox, first check its model catalog and authentication guide; register only with the intended route and billing conditions in view. This direct-provider example is not a claim of identical gateway configuration.

Before choosing where to fund access, use the provider buying checklist to confirm the model, protocol and billing terms.