DeepSeek
DeepSeek V4.1 Flash
A Flash model that reads text and images, built to make long, input-heavy agent workloads cheaper to run.
- Context window
- 1M tokens
- Accepts
- Text and images
- Input per 1M tokens
- $0.50
- Output per 1M tokens
- $1.50
Send your first request
Set LYCEUM_API_KEY to your API key, then run this request. Usage is billed to your account.
- Base URL
https://api.lyceum.technology/openai/v1- Model ID
deepseek/deepseek-v4.1-flash- Request fields
model, messages, stream, max_tokens, tools, tool_choice
Documented request fields for this endpoint. See the documentation for model-specific controls and limits.
app.py · Install openai and set LYCEUM_API_KEY
import os
from openai import OpenAI
client = OpenAI(
api_key=os.environ["LYCEUM_API_KEY"],
base_url="https://api.lyceum.technology/openai/v1",
)
response = client.chat.completions.create(
model="deepseek/deepseek-v4.1-flash",
messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)app.ts · Install openai and set LYCEUM_API_KEY in Node.js
import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.LYCEUM_API_KEY,
baseURL: "https://api.lyceum.technology/openai/v1",
});
const response = await client.chat.completions.create({
model: "deepseek/deepseek-v4.1-flash",
messages: [{ role: "user", content: "Hello!" }],
});
console.log(response.choices[0]?.message.content);Terminal · Set LYCEUM_API_KEY in your terminal
curl https://api.lyceum.technology/openai/v1/chat/completions \
-H "Authorization: Bearer $LYCEUM_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "deepseek/deepseek-v4.1-flash",
"messages": [
{"role": "user", "content": "Hello!"}
]
}'What it costs and how fast it runs
You pay only for the tokens you use. Speed figures come from our own status checks.
Token pricing
| USD per million tokens | |
|---|---|
| Input | $0.50 |
| Cached input | $0.13 |
| Output | $1.50 |
No base fee. Caching applies only where listed. Check the model's processing region before sending data.
Speed on Lyceum
| Last 7 days | |
|---|---|
| Time to first token | 259 ms |
| Output speed | 83 tokens/s |
Median over the last 7 days from our status checks: short requests. Measured 6 October 2026, 22:38 UTC. Reasoning tokens count towards both figures. Live status and availability
The model in detail
Checked against the sources below. Anything they don't state is left out.
Capabilities
- Input and output
- Text and images in, text out
- Context window
- 1M tokens
- Tool calling
- Supported
Architecture and licence
- Total parameters
- 552B backbone, plus 196B of Engram memory
- Active parameters
- 8B per token in prefill, 16B in decode
- Architecture
- Mixture of experts
- Licence
- MIT
- Released
- 10 September 2026
Availability
- API model ID
deepseek/deepseek-v4.1-flash- Provider
- DeepSeek
- Processing region
- EU-hosted
- Input and output types: official model card, checked 10 September 2026.
- Capabilities and request fields: Lyceum API documentation, checked 9 September 2026.
- Parameters, licence and release date: DeepSeek’s own sources, including its model card and announcement, checked 29 September 2026.
Common questions about DeepSeek V4.1 Flash
Short answers about the model ID, price, limits and behaviour.
What is the model ID for DeepSeek V4.1 Flash?
Use deepseek/deepseek-v4.1-flash as the model value. The OpenAI-compatible base URL is https://api.lyceum.technology/openai/v1. You authenticate with your Lyceum API key as a Bearer token.
How much does DeepSeek V4.1 Flash cost?
DeepSeek V4.1 Flash costs $0.50 per 1M input tokens, $0.13 per 1M cached input tokens and $1.50 per 1M output tokens. Prices are in US dollars. Billed per token. No base fee.
What is the context window of DeepSeek V4.1 Flash?
DeepSeek V4.1 Flash has a 1M tokens context window. One request can generate up to 65,536 tokens and run for up to 300 seconds. Set stream: true for long outputs.
Can DeepSeek V4.1 Flash read images?
Yes. Send images as OpenAI-style image_url content parts, from a public URL or a base64 data URL.
Can I turn off reasoning for DeepSeek V4.1 Flash?
Yes. Reasoning is on by default. Send reasoning_effort: "none" in the request. The reasoning trace counts as output tokens when it is on, so set max_tokens high enough for both the reasoning and the answer.
Does DeepSeek V4.1 Flash support tool calling?
Yes. Send tools in the standard OpenAI format. Automatic tool calls, parallel calls and tool-result round trips work. It does not enforce tool_choice: "required" or a named function. It can answer in plain text with no tool calls, so check message.tool_calls and fall back when it is empty.
Does DeepSeek V4.1 Flash support prompt caching?
Yes, and it is automatic. When requests share an identical start, the cached part is billed at $0.13 per 1M tokens instead of $0.50. Keep the stable part of your prompt at the front. A cache hit is best effort, so read usage.prompt_tokens_details.cached_tokens, which is missing on a miss.
Where does DeepSeek V4.1 Flash run, and is my data kept?
DeepSeek V4.1 Flash runs on EU-hosted infrastructure. Prompts and outputs are processed, not stored, and never used for training.
How do I call DeepSeek V4.1 Flash with the OpenAI SDK?
Point the OpenAI SDK at https://api.lyceum.technology/openai/v1, use your Lyceum API key and set model="deepseek/deepseek-v4.1-flash". Chat completions, streaming, tool calling and usage accounting work as they do with OpenAI.
Behaviour notes follow the Lyceum API documentation, checked 6 October 2026.
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