How to beginner · 3 min read

Cheapest LLM API in 2025

Q: Cheapest LLM API in 2025

The cheapest LLM APIs in 2025 include OpenAI's gpt-4o-mini and Anthropic's claude-3-5-haiku-20241022, both offering low-cost options for chat and code tasks. Open-source alternatives like llama.cpp are free but require self-hosting. Pricing varies by usage and model size.

Quick answer

The cheapest LLM APIs in 2025 include OpenAI's gpt-4o-mini and Anthropic's claude-3-5-haiku-20241022, both offering low-cost options for chat and code tasks. Open-source alternatives like llama.cpp are free but require self-hosting. Pricing varies by usage and model size.

PREREQUISITES

Python 3.8+
API key from chosen provider (OpenAI, Anthropic, Google, etc.)
pip install openai>=1.0 or anthropic>=0.20

Setup

Install the required Python SDK and set your API key as an environment variable for secure access.

bash

pip install openai anthropic

Step by step

Example using OpenAI's cheapest model gpt-4o-mini for a simple chat completion.

python

import os
from openai import OpenAI

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

response = client.chat.completions.create(
    model="gpt-4o-mini",
    messages=[{"role": "user", "content": "Hello, what is the cheapest LLM API in 2025?"}]
)

print(response.choices[0].message.content)

output

The cheapest LLM APIs in 2025 include OpenAI's gpt-4o-mini and Anthropic's claude-3-5-haiku-20241022, offering affordable pricing for various use cases.

Common variations

Use Anthropic's claude-3-5-haiku-20241022 model for cost-effective chat completions with their SDK.

python

import os
import anthropic

client = anthropic.Anthropic(api_key=os.environ["ANTHROPIC_API_KEY"])

message = client.messages.create(
    model="claude-3-5-haiku-20241022",
    max_tokens=512,
    system="You are a helpful assistant.",
    messages=[{"role": "user", "content": "What is the cheapest LLM API in 2025?"}]
)

print(message.content[0].text)

output

The cheapest LLM APIs in 2025 include Anthropic's claude-3-5-haiku-20241022 and OpenAI's gpt-4o-mini, both optimized for low-cost usage.

Troubleshooting

If you encounter authentication errors, verify your API key is correctly set in the environment variables. For rate limits, consider upgrading or optimizing request frequency.

✅

Key Takeaways

Use gpt-4o-mini or claude-3-5-haiku-20241022 for the lowest-cost LLM API usage in 2025.
Open-source models like llama.cpp offer free alternatives but require self-hosting and maintenance.
Always secure API keys via environment variables and monitor usage to control costs.

Verified 2026-04 · gpt-4o-mini, claude-3-5-haiku-20241022, llama.cpp

Verify ↗