phi-4
Phi-4 from Microsoft Research is a 14B-parameter model designed for complex reasoning that runs efficiently where memory is limited or quick responses are needed.
Pricing: Input 14 credits / 1M tokens (≈ $0.07), Output 28 credits / 1M tokens (≈ $0.14).
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Phi 4 API on ModelFold
Phi-4 from Microsoft Research is a 14B-parameter model designed for complex reasoning that runs efficiently where memory is limited or quick responses are needed. Try Phi 4 in the ModelFold Playground, then call it from your own code through an OpenAI-compatible chat completions API.
What Is the Phi 4 API
Phi 4 at a glance
Phi 4 is a chat model from Microsoft. It accepts text as input and returns text, with a context window of up to 16K tokens.
Use it without hosting anything
On ModelFold you call Phi 4 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 Phi 4
Up to 16K 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.
Structured outputs
Ask for JSON that follows a schema (response_format), which makes extraction, classification and system integrations more reliable.
How to Use Phi 4 on ModelFold
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Step 1: Try it in the Playground
Open the Playground at the top of this page, type a prompt and see how Phi 4 responds before writing any code.
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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.
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Step 3: Send a request
Call POST https://modelfold.ai/v1/chat/completions with "model": "phi-4" 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 Phi 4
Analysis and complex reasoning
Work through research questions, data interpretation, planning and other problems that need careful step-by-step reasoning.
High-volume pipelines
Run classification, extraction, rewriting and batch jobs at scale where cost per request matters.
Low-latency experiences
Power chat interfaces, autocomplete and interactive tools where users expect fast responses.
AI coding assistants
Generate, explain, debug and refactor code, review pull requests and work through multi-file changes in developer tools and IDE plugins.
Frequently Asked Questions
What is Phi 4?⌄
Phi-4 from Microsoft Research is a 14B-parameter model designed for complex reasoning that runs efficiently where memory is limited or quick responses are needed.
Which inputs does Phi 4 support?⌄
Phi 4 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 Phi 4?⌄
Up to 16K tokens, shared between your input and the model’s output.
Does Phi 4 support function calling?⌄
Function calling is not listed for Phi 4; requests that include tools will be rejected. Use plain prompts or JSON output instead.
How is Phi 4 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 Phi 4 through the API?⌄
Send a POST request to https://modelfold.ai/v1/chat/completions with "model": "phi-4", using your ModelFold API key as the Bearer token.
| Input | 14 credits 1M tokens≈ $0.07 |
| Output | 28 credits 1M tokens≈ $0.14 |
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":"phi-4","messages":[{"role":"user","content":"Hello"}]}'