Kimi K3 Free API: Benchmarks, Coding Performance, and Token Harbor Launch
Kimi K3 is one of the most ambitious open-weight AI models released in 2026. Moonshot AI built it for long-horizon coding, terminal work, multimodal tasks, research, and other agentic workflows.
From August 6, 2026 at 00:00 PDT to August 13, 2026 at 00:00 PDT, Token Harbor is offering free Kimi K3 API access through kimi-k3:free. This gives developers one week to test the model before committing a production budget.
The event runs for exactly one week, from August 6 at 00:00 PDT to August 13 at 00:00 PDT. Usage limits, eligibility, and capacity may change during the event.
Kimi K3 at a glance
Kimi K3 is an open-weight, native multimodal mixture-of-experts model from Moonshot AI.
| Specification | Kimi K3 |
|---|---|
| Total parameters | 2.8T |
| Active parameters | 104B |
| Context window | 1,048,576 tokens |
| Architecture | Mixture of Experts |
| Native input | Text and images |
| Reasoning effort | Low, high, and max |
| API compatibility | OpenAI- and Anthropic-compatible |
| Token Harbor model ID | kimi-k3 |
| Token Harbor paid price | $3 input / $15 output per 1M tokens |
Moonshot releases the model weights under the Kimi K3 License. Teams considering self-hosting or redistribution should read that license rather than assuming that “open weight” means unrestricted use.
Sources: Moonshot AI's official Kimi K3 model card and the Token Harbor model catalog.
Kimi subscription vs Token Harbor free API access
Kimi K3 has a one-million-token model context window, but the context available to a user depends on how the model is accessed.
Kimi's official Chinese membership page lists paid plans starting at ¥49 per month. K3 draws from the shared membership credit pool. For Kimi chat and workspace, the full one-million-token “extra-long conversation” benefit is reserved for the highest Allegro plan at ¥699 per month.
Kimi Code has a different entitlement structure. Its documentation states that K3 requires Moderato or above, while the one-million-token K3 option is available from Allegretto and above. Based on the current Chinese monthly prices, those plans cost ¥99 and ¥199 per month respectively.
| Access route | Entry requirement | Maximum K3 context |
|---|---|---|
| Kimi chat/workspace membership | Paid plans start at ¥49/month | 1M requires Allegro at ¥699/month |
| Kimi Code | K3 requires Moderato at ¥99/month | 1M from Allegretto at ¥199/month |
| Kimi API | Pay per token | 1,048,576 tokens |
Token Harbor kimi-k3:free | Eligible account during the event | Up to 1,048,576 tokens |
Token Harbor's kimi-k3:free route supports up to the full one-million-token context window on eligible requests. It does not require a Kimi subscription.
“Up to 1M context” describes the model's context capacity, not a promise of one million free tokens per account or unlimited usage. Event quotas, capacity, and output limits still apply.
Sources: Kimi's official K3 pricing guide, Kimi membership pricing, and Kimi Code model configuration.
Independent Kimi K3 benchmark results
Artificial Analysis currently gives Kimi K3 a score of 57 on its broader Intelligence Index. That index combines several capability areas and is not a coding-only benchmark.
For coding, Artificial Analysis evaluates Kimi K3 together with Kimi Code CLI as a complete agent configuration:
| Independent metric | Kimi K3 with Kimi Code CLI |
|---|---|
| Coding Agent Index v1.3 | 61 |
| DeepSWE | 64% |
| Terminal-Bench v2 | 84% |
| SWE-Atlas-QnA | 37% |
| Average time per task | 23.8 minutes |
| Average token usage per task | 10.6M |
These are not pure model scores: they include Kimi Code CLI, its tools, prompts, settings, and execution environment. Another harness may produce different results.
Sources: Artificial Analysis Kimi Code CLI comparison and Coding Agent Index methodology.
Official Kimi K3 coding benchmarks
Moonshot AI publishes a broader set of coding results in the Kimi K3 model card. The following selection compares Kimi K3 with Claude Fable 5 and GPT-5.6 Sol as reported in that table:
| Benchmark | Kimi K3 | Claude Fable 5 | GPT-5.6 Sol |
|---|---|---|---|
| DeepSWE | 67.5 | 70.0 | 73.0 |
| ProgramBench | 77.8 | 76.8 | 77.6 |
| Terminal-Bench 2.1 | 88.3 | 88.0 | 88.8 |
| FrontierSWE | 81.2 | 86.6 | 71.3 |
| SWE-Marathon | 42.0 | 35.0 | 39.0 |
| SciCode | 58.7 | 60.2 | 56.1 |
In this official comparison, Kimi K3 leads the three-model selection on ProgramBench and SWE-Marathon and nearly matches GPT-5.6 Sol on Terminal-Bench 2.1. Fable 5 remains higher on FrontierSWE and SciCode, while Sol is higher on DeepSWE and Terminal-Bench 2.1.
These figures are vendor-reported and use different agent harnesses: Kimi K3 uses Kimi Code for several tests, while Claude and GPT results may use Claude Code, Terminus 2, or Codex. Treat the table as useful evidence, not a controlled head-to-head experiment.
Source: Moonshot AI's Kimi K3 evaluation results and footnotes.
Where Kimi K3 looks strongest
Kimi K3 is designed for long engineering sessions, large repositories, and terminal tools. Its independent 84% Terminal-Bench v2 result and official FrontierSWE and SWE-Marathon results make terminal-heavy workflows an obvious test case.
Its one-million-token context can accommodate large codebases, documentation, and research inputs. Longer prompts still consume more tokens and can make relevant evidence harder to find.
Kimi K3 also combines native multimodal input, open weights, and OpenAI- and Anthropic-compatible APIs. Confirm that kimi-k3:free exposes the input type you need before planning a multimodal test.
What the benchmarks do not tell you
The Artificial Analysis run averaged 23.8 minutes and 10.6 million tokens per task. Public benchmarks cannot show your repository's test-pass rate, review effort, or whether a smaller model would finish faster. Measure those outcomes during the free event.
How to try Kimi K3 free on Token Harbor
The Kimi K3 free API promotion runs from August 6, 2026 at 00:00 PDT until August 13, 2026 at 00:00 PDT.
When the event opens:
- Create a Token Harbor account.
- Generate a Universal API Key.
- Select
kimi-k3:free. - Send a small test request before trying a repository-scale workflow.
- Track task success, latency, token use, retries, and required human edits.
Free access is not unlimited. Check the launch announcement and dashboard for quota, eligibility, concurrency, and capacity rules.
Token Harbor posts event rules and capacity updates on X, Discord, YouTube, and Product Hunt.
Frequently asked questions
Is Kimi K3 free?
Kimi K3 is normally paid on Token Harbor. Eligible users can access kimi-k3:free from August 6 at 00:00 PDT until August 13 at 00:00 PDT, subject to the published event limits.
Do I need a Kimi subscription to use Kimi K3?
Not through the Token Harbor API. During the launch event, eligible users can access Kimi K3 without a Kimi subscription, with support for up to the model's one-million-token context within event limits.
Is Kimi K3 good for coding?
Public evidence makes Kimi K3 a strong coding-agent candidate. Kimi K3 with Kimi Code CLI scores 61 on Artificial Analysis Coding Agent Index v1.3, including 64% on DeepSWE and 84% on Terminal-Bench v2. These scores measure the full agent configuration, not the model alone.
Does Kimi K3 support a one-million-token context window?
Yes. Moonshot lists a context length of 1,048,576 tokens. Actual usable input and output limits can still depend on the API provider and request configuration.
The bottom line
Kimi K3 combines open weights, native multimodal input, a one-million-token context window, and strong public coding-agent results. Its official benchmarks are competitive with leading frontier models, especially on terminal and longer software-engineering tasks, although differing harnesses mean the comparisons require care.
During Token Harbor's one-week free event, test Kimi K3 on your own repository, record the complete workflow, and decide whether its capability justifies its time and token use.
Browse Kimi K3 on Token Harbor · Create an API key · Follow on X · Join Discord