Kimi K3.1 vs Claude Opus 5.5: Pricing, Specs and the K3 Baseline

Kimi K3.1 vs Kimi K3 vs Claude Opus 5.5: confirmed specifications

The October 23 official Kimi video is a public demonstration. It does not establish general API access, a launch price or a benchmark win over Opus. The K3.1 release timeline records the earlier teaser and attributed configuration sightings.

K3's output ceiling is constrained by the combined context budget and serving route. It does not mean a request can contain 1M input tokens plus 1M output tokens. Confirm route support before sending long contexts, video or large output budgets. Kimi Code's k3 identifier and default effort are also separate from the public kimi-k3 API settings.

Official API pricing: K3 vs Opus 5.5, with K3.1 pending

These are vendor prices, independent of APIMaster discounts. All amounts are USD per million tokens for the stated service; cached input is separated from uncached input.

At standard uncached list prices, K3 is 25% cheaper on both input and output. The cached-input ordering differs: Opus's $0.20 cache read is below the $0.30 K3 cache-hit rate published in Kimi's technical blog. Cache creation, eligibility and lifetime still affect the bill. Kimi's current pricing guide describes cache-write rules, so consult it before treating a cache-hit rate as the total cache cost.

For a workload totaling 1M uncached input tokens plus 200K output tokens across multiple requests, official standard token charges are $6 for K3 and $8 for Opus 5.5. K3.1 cannot be costed yet. This example excludes caching, Fast service, tools and other charges.

APIMaster pricing: current routes and a separate cost comparison

This section uses APIMaster's live marketplace, checked October 23, 2026. Route availability and prices can change; the minimum price does not guarantee identical context limits, caching, throughput or tool support across routes.

At these minimum APIMaster rates, Opus 5.5's token charges are approximately 30.8% cheaper than K3's for the same input/output token counts. That conclusion applies to this marketplace snapshot. The official-price comparison above still favors K3 for uncached input and output.

The example is arithmetic, not a measured cost per completed task. A model can use more reasoning tokens, make more tool calls or need more retries. Official cache discounts are not automatically the cache prices of an APIMaster route; verify the selected model card and billing behavior.

For smaller budgets, the quick-answer table also includes Kimi K2.7 Code and Sonnet 5.5. Their lower prices do not establish the same capability as K3 or Opus.

Is Kimi better than Claude for coding and agents?

There is no verified K3.1-versus-Opus-5.5 result in this comparison. A coding demonstration supports trying a model when access arrives; it cannot supply a pass rate, production latency or a general ranking.

K3 is a useful candidate when you need video understanding, access to released weights or explicit public-API reasoning levels. Opus 5.5 is a useful candidate when you want adaptive reasoning and an existing Claude workflow; its current lowest APIMaster rate also makes it worth testing on cost-sensitive coding workloads. Confirm endpoint, tool-call and cache compatibility for the route you choose.

Both vendors publish coding and agent evaluations. Scores from different task versions, tools, effort settings or retry budgets do not form a controlled head-to-head test. This page leaves K3.1 performance unscored until a reproducible comparison is available.

How we will compare K3.1 when API access is confirmed

Use the same repository revision, prompts, tools, test suite, time allowance and retry policy for K3.1, K3 and Opus 5.5. Record reasoning settings explicitly: K3's public default is max, while Opus's documented default effort is medium.

After a documented public release, this comparison will add K3.1's confirmed identifier, official price, APIMaster route status and specifications. Independent task results will be labeled separately from vendor claims. The existing K3 baseline will remain so readers can judge the upgrade itself.

FAQ

Is Kimi K3.1 released?

Kimi has posted an official video. As of the October 23, 2026 check, the sources reviewed here do not establish a generally available public API, complete specifications or a public API price. See the dated release timeline.

Is Kimi K3 cheaper than Claude Opus 5.5 officially?

Yes for standard uncached tokens: K3 is $3 input / $15 output per 1M, versus $4 / $20 for Opus 5.5, a 25% reduction. Official cache-read prices differ, so a cache-heavy workload needs a separate calculation.

Which is cheaper on APIMaster?

At the October 23 check, Opus 5.5 starts at $1.340784 / $6.70392 and K3 at $1.938 / $9.69 per 1M input/output tokens. Opus's minimum token rates are approximately 30.8% lower. Use the live cards before purchasing; these are route prices, not measured task costs.

Can I call Kimi K3.1 through APIMaster now?

No active public route was found for either kimi-k3-1 or kimi-k3.1. The reported identifier is not a verified callable model ID. The released alternatives in this comparison are kimi-k3 and claude-opus-5-5.

Does Kimi K3.1 have K3's 1M context and 2.8T parameters?

That has not been confirmed. The 1,048,576-token context and 2.8T parameter count belong to K3's documentation. K3.1's context, output ceiling, parameter count and weight availability remain separate unknowns.

Is Kimi K3.1 better than Opus 5.5 for coding?

There is no verified head-to-head result here. Compare accepted changes, retries, latency and total successful-task cost under the same tools and budget once K3.1 is generally available.

Sources and API access

Checked October 23, 2026:

• Official Kimi video: public demonstration; not a public API pricing sheet.
• Kimi K3 technical blog: 2.8T architecture, modalities and published $3 / $15 / $0.30 rates.
• Kimi K3 public API guide: context, output budget, reasoning settings and released-weights statement.
• Kimi pricing guide: current billing and cache policy. Its numeric tables did not render in the retrieved source; K3 numeric prices above are attributed to the official technical blog.
• Anthropic Opus 5.5 announcement, model overview and pricing: release, limits and standard/cache/Fast prices.
• K3 marketplace data and Opus 5.5 marketplace data: active public APIMaster route snapshot.

To test the released models, compare K3 routes and Opus 5.5 routes, currently up to approximately 35% and 66% below their respective official standard token rates. Register, create an API key, then use https://apimaster.ai/v1 with kimi-k3 or claude-opus-5-5 on a compatible route. Start with a small representative task and verify the model, usage and final charge before scaling.