DeepSeek's October 17 V4.1 Flash snapshot is a 552B MoE with native vision and 1M context.
OpenRouter lists DeepSeek V4.1 Flash 1017, the October 17, 2026 snapshot of DeepSeek V4.1 Flash, served under the deepseek-flash API name. It is a sparse mixture-of-experts model and the first built on DeepSeek's Causal Encoder-Decoder architecture, activating 8B parameters on input and 16B on output from a 552B backbone. Native image understanding, a 1 million-token context, and compressed KV caching target coding, terminal, and computer-use agents. Listed pricing is $0.15 per million input tokens and $0.60 per million output tokens; DeepSeek says it exceeds V4 Pro on performance, speed, and task completion time.
October 17, 2026 snapshot of DeepSeek V4.1 Flash on the deepseek-flash API.
552B sparse MoE activates 8B parameters on input and 16B on output.
First DeepSeek model on Causal Encoder-Decoder architecture, with native image understanding.
1M context, compressed KV cache, priced at $0.15/$0.60 per million tokens.
DeepSeek says it beats V4 Pro on performance, speed, and task completion time.
DeepSeek V4.1 Flash 1017 is the October 17, 2026 snapshot of DeepSeek V4.1 Flash, served by DeepSeek under the deepseek-flash API model name. V4.1 Flash is a sparse mixture-of-experts model from DeepSeek, and the first built on the company's Causal Encoder-Decoder (CED) architecture. It activates 8B parameters on input and 16B on output from a 552B-parameter backbone, an asymmetric split that keeps per-token compute low relative to the model's total size. Image understanding is native to the architecture, with visual and text embeddings trained jointly from the start of pre-training rather than added afterward as in the earlier experimental V4 Flash Vision Exp Opens in new tab.
It is suited for coding, terminal, and computer-use agents, along with long-horizon tasks that must run to completion across many steps and long-context analysis. Compressed KV caching cuts cache memory to roughly a quarter of the previous Flash generation, significantly reducing costs on agentic workloads. DeepSeek positions it as the cost-efficient tier of the V4.1 family and reports that it exceeds V4 Pro Opens in new tab on performance, speed, and task completion time.
This model is hosted by one provider. OpenRouter forwards every request to it directly — no routing decisions to make.
Reasoning effort All Latency / throughput P50
Provider
Input/M
Output/M
Cache read/M
Latency
Throughput
Uptime
DeepSeek
$0.15
$0.60
$0.003
1.15 s
150 tps
--
Pricing
The average price customers actually pay for this model, next to the prices providers post. Caching and discounts mean the price actually paid is often well below the listed one.
Throughput is how fast the model writes (tokens per second — higher is better). Latency is total round-trip time (lower is better). TTFT is time-to-first-token — how long before you see anything appear (lower is better).
Throughput
150 tok/s
P50, best across providers
Latency
1.15 s
P50, best provider
All locations
Reasoning effort All 3 days
Not enough performance data to display yet.
Uptime
Uptime is the percentage of the past 3 days that at least one provider was responding to requests. Availability is the percentage of time that inference was successfully served. OpenRouter continuously monitors and uses the next-best provider when one returns an error.
Availability over the last 24 hours
OpenRouter Availability
99.36%
When an error occurs in an upstream provider, we can recover by routing to another healthy provider, if your request filters allow it. You can access per-provider uptime data programmatically through the Endpoints API. Learn more about our load balancing and provider routing options.
Apps
Public apps that send the most traffic to this model. Good signal for what real production workloads look like — and a hint at which use cases this model is best suited for.
Token volume and request traffic to this model over time.
Tokens
Prompt
978K
Completion
7K
Reasoning
6K
Prompt tokens measure input size. Reasoning tokens show internal thinking before a response. Completion tokens reflect total output length.
API
Drop-in code to call this model. OpenRouter's API is OpenAI-compatible — most SDKs work by just swapping the base URL. The only thing that changes between models is the model slug below.
1
Get your API key
Create an API key from your OpenRouter dashboard and set it as an environment variable:
Use deepseek/deepseek-v4.1-flash-1017 with the OpenRouter API:
OpenRouter supports reasoning-enabled models that can show their step-by-step thinking process. Use the reasoning parameter in your request to enable reasoning, and access the reasoning_details array in the response to see the model's internal reasoning before the final answer. When continuing a conversation, preserve the complete reasoning_details when passing messages back to the model so it can continue reasoning from where it left off. Learn more about reasoning tokens.
In the examples below, the OpenRouter-specific headers are optional. Setting them allows your app to appear on the OpenRouter leaderboards.
import { OpenRouter } from "@openrouter/sdk"; const openrouter = new OpenRouter({ apiKey: "<OPENROUTER_API_KEY>"}); // Stream the response to get reasoning tokens in usageconst stream = await openrouter.chat.send({ chatRequest: { model: "deepseek/deepseek-v4.1-flash-1017", messages: [ { role: "user", content: "How many r's are in the word 'strawberry'?" } ], stream: true }}); let response = "";for await (const chunk of stream) { const content = chunk.choices[0]?.delta?.content; if (content) { response += content; process.stdout.write(content); } // Usage information comes in the final chunk if (chunk.usage) { console.log("\nReasoning tokens:", chunk.usage.completionTokensDetails?.reasoningTokens); }}
Using third-party SDKs
For information about using third-party SDKs and frameworks with OpenRouter, please see our frameworks documentation.
3
Enable streaming
Add "stream": true to your request body to receive responses as server-sent events:
HTTP-Refereroptional — your site URL, for rankings
X-Titleoptional — your site name, for rankings
Modeldeepseek/deepseek-v4.1-flash-1017
Parameters
Name
Type
Default
Description
reasoning
map
—
Controls reasoning behavior for models that support thinking tokens, including whether reasoning is enabled, the reasoning effort, maximum reasoning tokens, and whether reasoning is excluded from the response.
max_tokens
integer
—
This sets the upper limit for the number of tokens the model can generate in response.
temperature
float
1
This setting influences the variety in the model's responses.
top_p
float
1
This setting limits the model's choices to a percentage of likely tokens: only the top tokens whose probabilities add up to P.
stop
array
—
Stop generation immediately if the model encounter any token specified in the stop array.
frequency_penalty
float
0
This setting aims to control the repetition of tokens based on how often they appear in the input.
presence_penalty
float
0
Adjusts how often the model repeats specific tokens already used in the input.
logprobs
boolean
—
Whether to return log probabilities of the output tokens or not.
top_logprobs
integer
—
An integer between 0 and 20 specifying the number of most likely tokens to return at each token position, each with an associated log probability.
tools
array
—
Tool calling parameter, following OpenAI's tool calling request shape.
tool_choice
string or object
—
Controls which (if any) tool is called by the model.
response_format
map
—
Forces the model to produce specific output format.
DeepSeek V4.1 Flash 1017 is the October 17, 2026 snapshot of DeepSeek V4.1 Flash, served by DeepSeek under the deepseek-flash API model name. V4.1 Flash is a sparse mixture-of-experts model from DeepSeek, and the first built on the company's Causal Encoder-Decoder (CED) architecture.
Where is the DeepSeek V4.1 Flash 1017 documentation?
The DeepSeek V4.1 Flash 1017 documentation on OpenRouter includes the Does DeepSeek V4 Have Vision? blog post. The quickstart covers API keys and your first request, and the API reference lists every parameter.
How much does DeepSeek V4.1 Flash 1017 cost?
DeepSeek V4.1 Flash 1017 costs $0.15/M input tokens and $0.60/M output tokens, with separate rates for Cache Read at $0.003/M tokens.
What is the context length of DeepSeek V4.1 Flash 1017?
DeepSeek V4.1 Flash 1017 has a 1,048,576 token context window. It supports up to 393,216 completion tokens.
Does DeepSeek V4.1 Flash 1017 support tool calling and structured outputs?
Yes. DeepSeek V4.1 Flash 1017 accepts tools and tool_choice for function calling. It supports response_format for JSON output, without JSON-schema enforcement.
What inputs and outputs does DeepSeek V4.1 Flash 1017 support?
DeepSeek V4.1 Flash 1017 accepts text and images as input and returns text.
Join the OpenRouter newsletter
Model usage data, product updates, and research reports. One email each week.
Subscribe
By subscribing you agree to receive the OpenRouter newsletter: model usage data, product updates, and research reports, about one email a week. Unsubscribe anytime via the link in every email. See our Privacy Policy.