DeepSeek V4.1 Flash

Text & chatNewAvailable
by DeepSeekModel ID: deepseek-v4-1-flash

DeepSeek's current Flash model (API name deepseek-flash, model version DeepSeek-V4.1-Flash): 1M-token context, up to 384K output tokens, JSON output, tool calls and vision input.

Price ยท 1M in / out
US$0.36 / US$1.44
Context
1,000,000 tokens
Max. output
384,000 tokens
Input โ†’ output
Text + Image โ†’ Text
Developer
DeepSeek
Updated
23 September 2026
01

Playground

Try DeepSeek V4.1 Flash

Chat

US$0.36/1M in
Try DeepSeek V4.1 Flash

Send a message. The answer arrives in full once the model is done (no streaming).

System prompt
Max. answer length (tokens)

This run

at most US$0.0015 ยท 0.15 credits reserved

Billed by the tokens actually used; the unused part of the reservation is refunded.

New here?

5 free credits (US$0.05) when you sign up with Google

Usable 24 hours after sign-up, up to 5 runs per day and at most 2 credits per run. Other sign-in methods start without credits. Enough for 33 runs of this model.

02

About DeepSeek V4.1 Flash

TL;DRAs of 23 September 2026

DeepSeek V4.1 Flash is a model by DeepSeek in the Text & chat category. On Railwail, DeepSeek V4.1 Flash costs US$0.36 per 1M input tokens and US$1.44 per 1M output tokens. The context window holds 1,000,000 tokens, and one response can be up to 384,000 tokens long.

DeepSeek-V4.1-Flash was released on 10 September 2026 and replaced DeepSeek V4 Flash, which DeepSeek retired the same day; the old name deepseek-v4-flash is temporarily routed to it for compatibility. The model has a 1M-token context window and up to 384K output tokens and supports JSON output, tool calls, chat prefix completion (beta), FIM completion in non-thinking mode and image input. DeepSeek bills a peak and a lower off-peak rate; railwail charges the peak rate.
03

Pricing

Prices in US dollars. Usage is charged from prepaid credits.
InputUS$0.36 / 1M tokens
OutputUS$1.44 / 1M tokens
  • Billed by the tokens each request actually uses.
  • 1 credit = US$0.01

Cost calculator

Price calculator

/ req.
/ req.

Total

US$0.11

11 credits

Per request

US$0.0011 ยท 0.11 credits

Each request is rounded up to 0.01 credits.

04

API

Call DeepSeek V4.1 Flash with your Railwail API key. Use this model ID in the request:
curl https://railwail.com/api/v1/chat/completions \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "deepseek-v4-1-flash",
    "messages": [
      {
        "role": "user",
        "content": "Explain what a vector database is in two sentences."
      }
    ],
    "max_tokens": 1024
  }'
Set your key as RAILWAIL_API_KEYCreate API key
05

Specifications

Model ID
deepseek-v4-1-flash
Developer
DeepSeek
Category
Text & chat
Input
Text, Image
Output
Text
Context window
1,000,000 tokens
Max. output
384,000 tokens
Billing
By usage (tokens or GPU time)
Released
10 September 2026
Lifecycle
Current version
Catalog entry updated
23 September 2026

Input parameters

Inputs and settings from the model's input schema. The example in the API section shows which of them the API accepts.

  • promptrequired

    User message

    Type: Text
    Default: โ€“
    Allowed values: up to 32,000 characters
  • top_p
    Type: Number
    Default: 1
    Allowed values: 0 to 1
  • stream
    Type: Yes/no
    Default: false
    Allowed values: โ€“
  • max_tokens
    Type: Integer
    Default: 4096
    Allowed values: 1 to 384,000
  • temperature
    Type: Number
    Default: 0.7
    Allowed values: 0 to 2
  • system_prompt

    Optional system instruction

    Type: Text
    Default: โ€“
    Allowed values: up to 8,000 characters

Tags

  • deepseek
  • open-weights
  • cost-efficient
  • long-context
  • 1m-context
  • anon-free
06

Use cases

07

Frequently asked questions

What is DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash is a model by DeepSeek in the Text & chat category. On Railwail you can call it with an API key through the Railwail API.

How much does DeepSeek V4.1 Flash cost on Railwail?

On Railwail, DeepSeek V4.1 Flash costs US$0.36 per 1M input tokens and US$1.44 per 1M output tokens. You are charged for what each request actually uses. Usage is paid from prepaid credits; 1 credit equals US$0.01.

What is the context window of DeepSeek V4.1 Flash?

The context window of DeepSeek V4.1 Flash holds 1,000,000 tokens. One response can be up to 384,000 tokens long.

How fast is DeepSeek V4.1 Flash?

There are not enough measured runs of DeepSeek V4.1 Flash on Railwail yet to state a run time. It depends on the input, the settings and the load at the provider.

Is DeepSeek V4.1 Flash better than Claude Fable 5.1?

That depends on the task. DeepSeek V4.1 Flash (DeepSeek) and Claude Fable 5.1 (Anthropic) are both models in the Text & chat category. The comparison page shows their prices and specifications side by side.

Compare DeepSeek V4.1 Flash and Claude Fable 5.1

Can DeepSeek V4.1 Flash process images?

Yes. DeepSeek V4.1 Flash accepts images as input in addition to text.

How do I use DeepSeek V4.1 Flash through the API?

Create a Railwail API key and send your request with the model ID deepseek-v4-1-flash. Code examples for curl, Python and JavaScript are in the API section of this page.

08

Comparable models

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Use DeepSeek V4.1 Flash via the API

One API key for every model on Railwail. Usage is charged from prepaid credits, 1 credit = US$0.01.