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Which LLM APIs Can You Use for Free?

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编辑部选型指南

The Bottom Line

Yes—but “free access to large-model APIs” usually does not mean unlimited, permanently free usage. More often, platforms offer free models, signup credits, or low-cost trials under pay-as-you-go pricing. These options are suitable for learning, prototyping, and small personal projects, but we do not recommend relying on them for production traffic from the outset.

When choosing a platform, our team mainly looks at three things: whether the free quota is clearly documented, whether the API is directly compatible with OpenAI, and whether overages or failed requests could result in unexpected charges. By these criteria, the following options are worth trying.

1. Want to minimize hassle? Choose an aggregation gateway

4ALL API is more of an all-in-one entry point. With a single key, you can access more than 200 models, making it suitable for developers who have not yet settled on a model and want to try several providers. It supports free trials of selected models and lets you split tokens and quotas by project. If you later need to submit expenses to your company, its business invoicing and multiple payment options are also convenient. Before integrating it into a project, we recommend checking the official documentation to confirm the free usage policy for the specific model you plan to use.

If you are already using the OpenAI SDK, 4All API can significantly reduce migration costs. It focuses on OpenAI compatibility and provides relatively complete documentation and examples. Many projects can get up and running by simply changing the Base URL. For beginners, this is more practical than learning the request format used by each platform.

2. Mainly interested in images and video?

Beyond text models, if you want to experiment with image or video generation, take a look at OmniAPI. It covers capabilities such as GPT-Image 2K/4K, VEO 3.1, and Omni Flash. However, these tasks are generally more computationally intensive, so free trials often come with queueing, rate, or quota limits. They should not be interpreted as “unlimited generation.”

3. A few common pitfalls

First, the availability of free models may change at any time, so your code should handle timeouts and rate limits and provide fallback models. Second, check whether the platform has a “no charge for failed requests” policy. Otherwise, invalid parameters, timeouts, and retries may also consume your quota. Third, never put your primary account key directly in frontend code or commit it to GitHub. It is best to split tokens by project and set usage limits.

Overseas platforms such as OpenRouter are also worth considering, but payment and network conditions may be less convenient for some users. My recommendation is to start with a gateway that supports free models and OpenAI compatibility during the learning phase. Once your proof of concept works, switch to paid models based on stability, pricing, and privacy requirements. If you are looking for a transparent token-based billing solution, you can also keep an eye on TokenNode, which is launching soon.

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Published by the 4All API team

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