deepseek-r1-0528
DeepSeek R1 0528 is the May 28 update to the original DeepSeek R1: an open-source reasoning model with fully open reasoning tokens, 671B parameters in size with 37B active.
Pricing: Input 100 credits / 1M tokens (≈ $0.50), Output 430 credits / 1M tokens (≈ $2.15).
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R1 0528 API on ModelFold
DeepSeek R1 0528 is the May 28 update to the original DeepSeek R1: an open-source reasoning model with fully open reasoning tokens, 671B parameters in size with 37B active. Try R1 0528 in the ModelFold Playground, then call it from your own code through an OpenAI-compatible chat completions API.
What Is the R1 0528 API
R1 0528 at a glance
R1 0528 is a chat model from DeepSeek. It accepts text as input and returns text, with a context window of up to 164K tokens.
Use it without hosting anything
On ModelFold you call R1 0528 with a single API key — no model weights to download and no inference servers to run. The same key also works for the other chat, image, video and audio models on ModelFold.
Core Capabilities of R1 0528
Up to 164K tokens of context
Keep long conversations, large documents and sizeable code in a single request, so the model can reason over the full material instead of fragments.
Function calling
R1 0528 supports tool (function) calling: describe your functions in the request and the model returns structured calls your code can run — the basis for agents and integrations.
Reasoning mode
R1 0528 can produce reasoning before its final answer; in the Playground you can switch reasoning on or off to compare results.
Structured outputs
Ask for JSON that follows a schema (response_format), which makes extraction, classification and system integrations more reliable.
How to Use R1 0528 on ModelFold
- 1
Step 1: Try it in the Playground
Open the Playground at the top of this page, type a prompt and see how R1 0528 responds before writing any code.
- 2
Step 2: Create an API key
Sign in to ModelFold and create an API key in the console. Keep it secret and send it as a Bearer token.
- 3
Step 3: Send a request
Call POST https://modelfold.ai/v1/chat/completions with "model": "deepseek-r1-0528" and your messages. Existing OpenAI-compatible SDKs work by changing the base URL and key.
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Step 4: Ship and monitor
Integrate the response into your product and check token usage and spend for every call in the console logs.
What You Can Build with R1 0528
Analysis and complex reasoning
Work through research questions, data interpretation, planning and other problems that need careful step-by-step reasoning.
AI coding assistants
Generate, explain, debug and refactor code, review pull requests and work through multi-file changes in developer tools and IDE plugins.
Autonomous agents
Build agents that plan multi-step tasks, call your tools and APIs, and keep working toward a goal across long sessions.
Long-document workflows
Feed in long reports, contracts, manuals or codebases and ask for summaries, comparisons and answers grounded in the material.
Frequently Asked Questions
What is R1 0528?⌄
DeepSeek R1 0528 is the May 28 update to the original DeepSeek R1: an open-source reasoning model with fully open reasoning tokens, 671B parameters in size with 37B active.
Which inputs does R1 0528 support?⌄
R1 0528 accepts text and returns text. Through ModelFold you send text messages; documents attached in the Playground are converted to text.
How long is the context window of R1 0528?⌄
Up to 164K tokens, shared between your input and the model’s output.
Does R1 0528 support function calling?⌄
Yes. R1 0528 supports tools / function calling through the standard tools parameter of the chat completions API.
How is R1 0528 billed on ModelFold?⌄
Pay as you go by tokens: input and output tokens are charged at the per-million-token prices shown on this page. There is no monthly fee, and failed requests are not charged.
How do I call R1 0528 through the API?⌄
Send a POST request to https://modelfold.ai/v1/chat/completions with "model": "deepseek-r1-0528", using your ModelFold API key as the Bearer token.
| Input | 100 credits 1M tokens≈ $0.50 |
| Output | 430 credits 1M tokens≈ $2.15 |
Billed per token: input and output are priced separately, and thinking tokens count as output. The Playground charges exactly the same way.
Read API docs →AI Agents · Claude Code / Cursor / Trae →curl https://modelfold.ai/v1/chat/completions \
-H "Authorization: Bearer $MODELFOLD_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"deepseek-r1-0528","messages":[{"role":"user","content":"Hello"}]}'