# Is Kimi K3 free? Open weights, API costs and free credit

By SeedRouter · Published 2026-09-28 · Updated 2026-09-28

Kimi K3 is free to download but not free to use. Moonshot AI has released the full model weights, so anyone can get them at no cost. Running a 2.8-trillion-parameter model, though, takes data-center hardware, and Moonshot's own API bills Kimi K3 per token. The cheapest way to try it is a free trial balance on an API platform; on SeedRouter, every new account starts with a small free balance.

## Is Kimi K3 open source?

Yes. Moonshot AI calls Kimi K3 "the world's first open-source model in the 3-trillion-parameter class", and its [quickstart](https://platform.kimi.ai/docs/guide/kimi-k3-quickstart) states that "the full model weights have been released". Downloading the weights costs nothing. Read the license that ships with them before using the model commercially.

## Can I run Kimi K3 locally for free?

Only if you already own very large hardware. Kimi K3 has 2.8 trillion parameters. It activates 16 of its 896 experts per token, which keeps compute per token down, but all the weights still have to sit in memory. That is a multi-GPU server, not a laptop or a single consumer graphics card.

For most people, the electricity and hardware cost more than calling Kimi K3 through an API.

## Is the Kimi K3 API free?

No. Moonshot's own API bills Kimi K3 per token, and the model is unlocked only after a successful top-up. SeedRouter bills it per token too.

What differs between platforms is how you start:

| Where                        | How you start                         | Pay before the first call? |
| ---------------------------- | ------------------------------------- | -------------------------- |
| Moonshot's Kimi API Platform | Top up before Kimi K3 unlocks         | Yes                        |
| SeedRouter                   | A small free balance on a new account | No                         |

Kimi's chat app and its other products are sold separately with their own plans; this guide covers the API.

## How far does the free balance go?

Kimi K3 is billed per input and output token, and it reasons on every request, so the answer to a short question costs a fraction of a cent. The live rates:

### Kimi K3

Current rates are temporarily unavailable. No price estimate is provided; unavailable rates must not be interpreted as free usage.

The free balance covers dozens of short test requests at `low` reasoning effort: in our test, a two-paragraph answer at `low` used about 100 input and 190 output tokens. Longer prompts and `max` effort use more of it, because reasoning is billed as output.

## How do I try Kimi K3 for next to nothing?

1. Create a SeedRouter account; the free balance is added automatically.
2. Open the [Kimi K3 playground](https://seedrouter.ai/models/kimi-k3#playground) and send a short prompt with reasoning effort `low`.
3. Check the tokens and cost under each answer, then decide whether to top up.

A request that fails is not charged, so a bad prompt or a wrong parameter does not cost you anything.

## How do I keep Kimi K3 cheap after the trial?

* Use `low` or `high` effort unless a task needs `max`: reasoning is output, and output is the dearest line.
* Put long, reused context at the start of the prompt. Kimi K3 caches repeated prefixes automatically, and cached input costs a tenth of fresh input.
* Set `max_completion_tokens` so a runaway answer cannot use your whole balance.

The [Kimi K3 pricing guide](https://seedrouter.ai/blog/kimi-k3-api-pricing) has the billing formula and worked examples.

## Frequently asked questions

### Is there a free Kimi K3 API key?

No key is free to use indefinitely. A SeedRouter key comes with a small free balance on a new account; after that you pay per token.

### Is Kimi K3 free for commercial use?

The weights are free to download, and the license that comes with them sets the terms for commercial use. Calling Kimi K3 through an API is paid per token either way.

### Do I need a subscription for Kimi K3?

Not on SeedRouter. You top up a balance and pay per token, with no plan and no monthly fee.

### How do I call Kimi K3 from code?

The [Kimi K3 API guide](https://seedrouter.ai/blog/kimi-k3-api) shows how to get a key and make the first call.