Is R1 0528 available on FastMetal?

Not at the moment. DeepSeek V4.1 Flash, from the same lab, is available on the FastMetal API today.

What is the context window of R1 0528?

163,840 tokens, shared between the prompt and the response.

How does R1 0528 rank?

#79 on the public arena's Japanese board (ELO 1,392). Ranks move as the leaderboard is updated.

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deepseek/deepseek-r1-0528

Not Available

R1 0528

May 28th update to the [original DeepSeek R1](/deepseek/deepseek-r1) Performance on par with [OpenAI o1](/openai/o1), but open-sourced and with fully open reasoning tokens. It's 671B parameters in size, with 37B active in an inference pass. Fully open-source model.

5/28/2025

163,840 tokens

#79 Text (Japanese)

Specifications

Modalities

Input

text

Output

text

Supported Parameters

frequency_penalty

include_reasoning

logit_bias

logprobs

max_tokens

min_p

presence_penalty

reasoning

repetition_penalty

response_format

seed

stop

structured_outputs

temperature

tool_choice

tools

top_k

top_logprobs

top_p

Max Output Tokens

65,536

Reasoning Configuration

Default: Thinking on
Turning thinking off: Not possible (always thinks)

How to control thinking, and what it costs

Frequently asked questions

Is R1 0528 available on FastMetal?: Not at the moment. DeepSeek V4.1 Flash, from the same lab, is available on the FastMetal API today.
What is the context window of R1 0528?: 163,840 tokens, shared between the prompt and the response.
How does R1 0528 rank?: #79 on the public arena's Japanese board (ELO 1,392). Ranks move as the leaderboard is updated.