Anthropic
Claude Opus 5
From $2.40 per 1M tokens
Chat
Kimi K3 — 1M Context, Open-Weight Flagship
Kimi K3 is Moonshot's flagship model for long-horizon coding and end-to-end knowledge work. Kimi K3 reads a 1,048,576-token context window, always reasons, and takes a three-rung reasoning-effort dial that runs from low to max. Native vision covers images and video, the weights are open, and on reAPI Kimi K3 bills below Moonshot's published per-token rate on both input and output.
Kimi K3model
kimi-k3Kimi K3 playground
Chat models run on the api.reapi.ai gateway, which has its own console and its own key. Open the console to run Kimi K3 through the OpenAI-compatible Chat Completions surface.
What you can build with this model
Real-world workflows and production use cases you can build and ship with this model.
Long-horizon coding, with screenshots in the loop
Moonshot positions Kimi K3 for long-horizon coding, and describes it running engineering tasks with minimal human supervision — working through large codebases and coordinating terminal tools. What separates Kimi K3 from a text-only coding model is that vision is native rather than bolted on: it takes screenshots and visual feedback as input, which Moonshot calls out specifically for game development, frontend engineering and CAD. That closes the loop a text-only model cannot close, because the model can look at what it just built and judge whether the layout is actually wrong before it edits again.
Read the API docs
A million tokens of knowledge work with no chunking layer
The Kimi K3 context window is 1,048,576 tokens, and Moonshot's own FAQ says the rate is flat with no tiering by context length — so filling the window costs what any other token costs. A contract set, a research bundle or a year of filings goes to Kimi K3 whole, which removes the retrieval layer whose only job was working around a small context. Context caching then does the repeat work: it is automatic on Kimi K3, with no cache id, no TTL and no extra parameter, so a stable prefix in front of a changing question is the pattern to build around.
Agents that are made to call tools, not talked into it
Two tool-calling controls arrived with this generation. A required tool choice forces at least one call on the turn, which is how you stop an agent from answering from memory when it was supposed to look something up — the K2 models reject that setting, Kimi K3 accepts it. And a tool can be introduced partway through a conversation by putting its full definition in a system message, so a large tool inventory does not have to be declared up front on every request. Structured outputs and a JSON Schema keep whatever Kimi K3 returns parseable at the end of the loop.
Pricing
Credit-based — 1 credit = $0.001 USD. Pay only for completed generations.
| Category | Unit | Price |
|---|---|---|
| Token pricing | ||
| Input | 1M tokens | $2.5 |
| Output | 1M tokens | $12 |
Why reAPI
Below the published rate, both directions
Moonshot publishes a per-million-token rate for Kimi K3 input and output. On reAPI, Kimi K3 bills below it on both, and a full fifth below on output — no subscription underneath it, no minimum commitment, pay-as-you-go in USD against your gateway balance. The exact numbers are in the pricing table on this page.
OpenAI-compatible drop-in
Kimi K3 is served from a standard `/v1/chat/completions` endpoint, and Moonshot's own quickstart drives the model through the OpenAI SDK — so the compatibility is the vendor's design, not a shim. Adopting Kimi K3 is a base URL, a key and a model string. No SDK swap, and nothing about Kimi K3 needs a bespoke client.
One key across Kimi, Claude, GPT and Gemini
The same api.reapi.ai key that calls Kimi K3 calls the Claude, GPT and Gemini families too. Putting Kimi K3 head to head with a closed frontier model, or failing over when one provider has a bad hour, is a model string rather than a second integration, a second invoice and a second set of credentials.
Kimi K3 vs Claude Opus 5
On reAPI these two land at effectively the same per-token rate, which makes price the least interesting part of the comparison. What differs is shape: Kimi K3 is the open-weight model that always reasons, hands its reasoning text back and takes video input, while Claude Opus 5 is the closed model with a finer effort ladder that keeps its reasoning to itself. Two of these rows are the ones that break code carried over from another provider — thinking cannot be switched off on Kimi K3, and its reasoning text has to be echoed back in multi-turn histories.
Capability
Kimi K3 on reAPI
Claude Opus 5
Weights
Open — Moonshot calls it the first open-source model in the three-trillion-parameter class
Closed — API access only
Context and output limits
1,048,576-token context; output defaults to 131,072 and can be raised to the whole window
1M-token context; 128k maximum output, fixed
Thinking
Always on and cannot be disabled — lower the effort instead
On by default, and can be disabled at effort high or lower
Effort ladder
Three rungs — low, high, max — defaulting to max
Five rungs from low through max, defaulting to high
Reasoning text
Returned alongside the answer, and required back in the next request
Raw reasoning never returned; a readable summary on request
Visual input
Images and video, as base64 or an uploaded file — public URLs rejected
Images and PDF; no video input
Comparison reflects behavior documented by each vendor at the time of writing. Rates are described as relationships rather than amounts; the live numbers for Kimi K3 are in the pricing table above.
Ship Kimi K3 in three steps
- step 01
Create an account and key on api.reapi.ai
Sign up at api.reapi.ai, open the console and generate an API key. That one key reaches Kimi K3 and every other model on the gateway, billed from a single balance.
Open - step 02
Point your client at the gateway
Set your base URL to api.reapi.ai and your key to the one you just created. Any client that already speaks OpenAI Chat Completions works unchanged — no SDK swap is needed to reach Kimi K3.
Open - step 03
Send `kimi-k3` as the model
Set the model field to `kimi-k3` and post your messages. Turn on streaming for long outputs, drop any temperature or top_p you were sending, and pick a reasoning effort — Kimi K3 always thinks, and the default rung is the most expensive one.
Open
Frequently asked questions
Common questions about this model.
Kimi K3 is billed pay-as-you-go in USD per token against your api.reapi.ai balance, with separate input and output rates and no subscription. Both sit below Moonshot's published per-token rate, output by a full fifth. Current numbers are in the pricing table on this page.
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