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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
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
65,536Reasoning Configuration
- Default
- Thinking on
- Turning thinking off
- Not possible (always thinks)
Data policy
- Prompt retention
- Unknown — we could not confirm
- Training
- Unknown — not declared
"Unknown" does not mean "safe". It means we could not confirm it.
Whether a provider trains on prompts is a declared value from our terms with them. Retention is determined from the upstream listing for every host this model can reach. Neither is guessed.
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.