How to beginner · 3 min read

How to upload files to OpenAI API

Q: How to upload files to OpenAI API

Use the OpenAI Python SDK's client.files.create() method to upload files to the OpenAI API. Provide the file path and purpose (e.g., fine-tune) as parameters to upload your file successfully.

Quick answer

Use the OpenAI Python SDK's client.files.create() method to upload files to the OpenAI API. Provide the file path and purpose (e.g., fine-tune) as parameters to upload your file successfully.

PREREQUISITES

Python 3.8+
OpenAI API key (free tier works)
pip install openai>=1.0

Setup

Install the official openai Python SDK and set your API key as an environment variable.

Install SDK: pip install openai>=1.0
Set environment variable: export OPENAI_API_KEY='your_api_key' (Linux/macOS) or setx OPENAI_API_KEY "your_api_key" (Windows)

bash

pip install openai>=1.0

Step by step

This example uploads a local JSONL file for fine-tuning using the client.files.create() method. Replace path/to/yourfile.jsonl with your actual file path.

python

import os
from openai import OpenAI

client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])

response = client.files.create(
    file=open("path/to/yourfile.jsonl", "rb"),
    purpose="fine-tune"
)

print("File ID:", response.id)
print("Filename:", response.filename)
print("Status:", response.status)

output

File ID: file-abc123xyz
Filename: yourfile.jsonl
Status: uploaded

Common variations

You can upload files for different purposes such as fine-tune, answers, or search. The file parameter accepts any binary file object.

Use async upload with asyncio and await client.files.create(...) in async context.
Use different models with uploaded files for fine-tuning or embeddings.

python

import asyncio
import os
from openai import OpenAI

async def upload_file_async():
    client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
    response = await client.files.create(
        file=open("path/to/yourfile.jsonl", "rb"),
        purpose="fine-tune"
    )
    print("Async File ID:", response.id)

asyncio.run(upload_file_async())

output

Async File ID: file-abc123xyz

Troubleshooting

If you get a FileNotFoundError, verify the file path is correct and accessible.
If you see 401 Unauthorized, check your OPENAI_API_KEY environment variable.
For 400 Bad Request, ensure the file format matches the purpose (e.g., JSONL for fine-tuning).

✅

Key Takeaways

Use client.files.create() with a binary file object and a purpose to upload files.
Set your API key securely in os.environ["OPENAI_API_KEY"] before running code.
File format must match the intended purpose (e.g., JSONL for fine-tuning).
Async uploads are supported with await client.files.create() in async functions.
Check file path and API key environment variable if upload fails.

Verified 2026-04 · gpt-4o

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