What “free” actually means when an AI model is open.
A frontier coding model, given away, running on someone else’s GPUs for a year — it sounds too good to be true, and it partly is. The catch isn’t a scam; it’s a set of trade-offs. Compare the two worlds on the 3D cube below.
Drag to rotate · axes: openness · your control · your cost
Three words people mix up
Open-weight means the trained model file (its billions of parameters) is downloadable — you can run it yourself, fine-tune it, no permission needed. Models like Meta’s Llama, Mistral, DeepSeek and Kimi ship this way. It is not the same as open source: most open-weight releases don’t publish the training data or full training code, so you can use the model but not fully reproduce it. And “free API access” is different again — the weights may be open, but a company (or a partner like a GPU cloud) is paying to host inference so you don’t have to.
So “free coding model + free API key for a year” usually decodes to: the weights are open, and a hardware partner is subsidising the compute to win developers. Real cost, borne by someone else, for a strategic reason.
| Term | What’s shared | What’s not |
|---|---|---|
| Open-weight | the model file, to run & fine-tune | often training data & recipe |
| Open source | weights + code + (ideally) data | — |
| Free API | hosted access, no download | the weights; you depend on the host |
The trade-offs to weigh before you build on it
Upside: zero licence cost, no vendor lock-in (you can always download the weights and move), full fine-tuning, and — if you self-host — data that never leaves your machine. For hobby projects and startups avoiding per-token bills, that’s enormous.
Downside: a free hosted tier can rate-limit, change terms, or disappear when the promotion ends; performance still trails the very top closed models on the hardest tasks; and running the weights yourself needs serious GPUs (a large model can require tens of gigabytes of VRAM). “Free” shifts the cost from a licence fee to your own time, hardware, or dependence on a subsidised host. Toggle to Self-hosted above to see control go up and convenience go down — the fundamental trade of the open-weight world.
Sensible rule: prototype on the free hosted key, but design so you can switch providers — because the one thing a subsidised offer guarantees is that its terms will eventually change.