Use the DeepSeek V4.1 Flash 1017 API to add text generation, code assistance, and document analysis to your application. Create a key in your account, send a request, and track its token usage and cost.
Connect to the API
| Setting | Value |
|---|---|
| Base URL | https://deepseekv41flash.com/api/v1 |
| Chat endpoint | POST /chat/completions |
| Model | deepseek-flash |
| Authentication | Authorization: Bearer YOUR_API_KEY |
| Content type | application/json |
| Retry protection | Idempotency-Key containing a UUID |
Use an API key created on this website. A key from DeepSeek's official platform will not authenticate with this endpoint. Keep your key on your server or in a secret store; never include it in browser code or a public repository.
The API uses the deepseek-flash alias. DeepSeek currently maps that alias to the 1017 update, but it may point to a later version in the future. Official model details.
Send your first request
- Sign in and create an API key.
- Choose a credit source: claim the trial in your account, or add a paid balance.
- Set
SITE_ORIGINtohttps://deepseekv41flash.com,SITE_API_KEYto your key, andREQUEST_UUIDto a new UUID. - Run the example above. Check
choices[0].message.contentfor the answer andusagefor token counts. - Open Usage and requests to review the charge and request status.
Requests use paid credit by default. To spend trial tokens, add -H "X-Credit-Source: trial" to the example. A trial request never falls back to your paid balance.
Supported parameters
| Field | Accepted values |
|---|---|
model |
deepseek-flash |
messages |
1–32 text messages with system, user, or assistant roles |
| Message content | Up to 32,000 characters across all messages |
max_tokens |
1–8,192; defaults to 2,048 |
reasoning_effort |
none, low, high, or max; defaults to none |
stream |
false |
Our endpoint supports text chat. Images, tool calls, streaming, and additional request fields are not accepted. The model's upstream context window is larger than this service's request limit.
Thinking mode
Use none for a direct response without thinking. Choose low, high, or max to enable thinking at the requested effort level. More reasoning can increase output usage and response time. Reasoning tokens reported as output are included in the output charge, not billed a second time.
Read usage and charges
The response includes total input, cached input, uncached input, and output counts. Cached and uncached input add up to total input; do not count cached tokens twice.
The billing object contains the request ID and charged_nano_usd. Divide that amount by 1,000,000,000 to get USD. For trial requests, the USD charge is zero and trial_tokens_charged shows the allowance used.
A paid request places a temporary hold on your balance before it reaches the model. Once usage is confirmed, only the actual cost is charged and the remaining hold is released. A result that cannot be confirmed stays under review. See API pricing for rates and examples.
Retry without duplicate charges
Reuse the same Idempotency-Key, request body, and credit-source header when retrying an interrupted request. A completed request returns its stored response without another model call. A pending request stays pending; it is not run again.
Changing the body or credit source while reusing the same key returns IDEMPOTENCY_CONFLICT. Creating a new key starts a separate request and may incur another charge.
API input and output are retained for seven days; Playground content is retained for 30 days. After content expires, a repeat request returns RESPONSE_CONTENT_EXPIRED instead of running again. Usage and billing records are kept separately. Read our privacy policy.
Common errors
My API key is rejected
Check that the key was created on this website, has not been revoked, and is sent as a Bearer token. Confirm that your application is loading the intended key without extra spaces. Never send a key to support.
My request is rejected
Use the parameters listed above. Check message roles, total input length, and the output limit. Remove images, tool definitions, streaming options, or other unsupported fields.
My balance is too low
A paid request needs enough available balance for its temporary hold. Reserved credit cannot fund another request. Check your balance and any pending requests. Trial users can shorten their prompt or reduce the output limit to fit their remaining allowance.
The answer ends early
Check finish_reason. A value of length means the output limit was reached. Increase max_tokens within the supported range if you need a longer answer. A new request uses additional tokens.
A request timed out
Check the request status before starting another one. Retry with the original UUID and unchanged body; a connection failure does not necessarily mean the model did no work.
The service is unavailable
Check the availability notice on this page or in your account. If a request remains unresolved, contact support with its request ID and the time it occurred.