Using Phi-3 Mini 128K on Fireworks AI

Implementation guide · Phi-3 · Microsoft Research

ProvisionedOpen Source

Fireworks AI exposes Phi-3 Mini 128K through model ID phi-3-mini-128k. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.

Last refreshed 2026-09-21. Next refresh: weekly.

Quick Start

  1. 1
    Create an account at Fireworks AI and generate an API key.
  2. 2
    Use the Fireworks AI SDK or REST API to call phi-3-mini-128k — see the documentation for request format.
  3. 3
    You'll be billed $0.10/1M input, $0.10/1M output tokens. See full pricing.

Code Examples

Install
pip install openai
API key
FIREWORKS_API_KEY
Model ID
phi-3-mini-128k

Fireworks model IDs use "accounts/fireworks/models/{model-name}" format, e.g. "accounts/fireworks/models/llama4-scout-instruct-basic" or "accounts/fireworks/models/deepseek-r1".

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["FIREWORKS_API_KEY"],
    base_url="https://api.fireworks.ai/inference/v1"
)
response = client.chat.completions.create(
    model="phi-3-mini-128k",
    messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)

Pricing on Fireworks AI

TypePrice (per 1M)
Input tokens$0.10
Output tokens$0.10

Capabilities

No model capability flags are currently sourced.

About Phi-3 Mini 128K

Phi-3 Mini-128K-Instruct, developed by Microsoft, is a 3.8 billion-parameter large language model renowned for its lightweight, open-source architecture. Despite its modest size, it excels in reasoning tasks, particularly in math and logic, and showcases strong code generation capabilities. A standout feature is its remarkable ability to handle up to 128,000 tokens, allowing it to process extensive text documents and codebases efficiently. While it has limitations in factual knowledge and focuses primarily on English, it strikes a balance between performance and efficiency, making it ideal for resource-constrained environments.

Model Specs

Released2024-04-23
Parameters3.8B
Context128k
ArchitectureDecoder Only
Knowledge cutoff2023-10

Provider

Fireworks AI

San Mateo, California, United States