Kimi K3 API pricing and setup
Kimi K3 (kimi-k3) is a Moonshot model. It is available through the relay.fast API with one relay.fast key and pay-as-you-go billing.
Prices checked from the live catalog. "From" is the lowest price among the relay.fast sources that currently serve the model. The price you pay depends on the source your request uses and can change on any day. The pricing page always shows current values.
| Official input price | $3 per 1M tokens |
|---|---|
| Official output price | $15 per 1M tokens |
| relay.fast input from | $0.15 per 1M tokens |
| relay.fast output from | $0.75 per 1M tokens |
| Cache read from | $0.015 per 1M tokens |
| Lower than the official price by | up to 95% |
| Context window | 1.05M tokens |
| Endpoints | /v1/chat/completions |
Example request
Keep the key in the RELAY_FAST_API_KEY environment variable.
curl https://relay.fast/v1/chat/completions \
-H "Authorization: Bearer $RELAY_FAST_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"kimi-k3","messages":[{"role":"user","content":"Hello"}]}'Use Kimi K3 in coding tools
Setup guides: Claude Code, Codex, Cursor, Cline, Kilo Code, OpenCode, Aider. The API docs have one-command installers.
Frequently asked questions
How much does the Kimi K3 API cost?
On 2026-11-05, relay.fast charges from $0.15 per 1M input tokens and $0.75 per 1M output tokens for Kimi K3, against the official $3 and $15. The price depends on the source your request uses and can change; https://relay.fast/pricing/kimi-k3 shows the current value.
What is the context window of Kimi K3?
Kimi K3 accepts up to 1.05M tokens of context in the relay.fast catalog. Output limits depend on the model and client settings.
Which API endpoint does Kimi K3 use?
Call /v1/chat/completions with a relay.fast API key. OpenAI-compatible SDKs use the base URL https://relay.fast/v1.
Do I need a Moonshot account to use Kimi K3?
No. You use a relay.fast account and API key. relay.fast is an independent API gateway and is not affiliated with Moonshot.