Complex-task reasoning model for long-horizon programming and visual analysis
Kimi K3 is Moonshot AI's open-weight native multimodal model, focused on long-horizon programming, complex reasoning, and knowledge work. The official model card discloses a native context window of one million tokens, supporting the use of text and visual cues together for engineering analysis and content creation. On this platform, messages can be organized through standard Chat Completions; terminals, research retrieval, and file processing are provided by application workflows.
Choose an available protocol for this model. OpenAI SDK uses a Base URL ending in /v1; Anthropic SDK uses the root URL. See each guide for protocol-specific parameters, tools and response formats.
Specifications and interface features
First, clarify this model's inputs and standard invocation method.
Model identifier
kimi-k3
Input and output
Text and image message input; assistant text output
Standard API
POST /v1/chat/completions; submit model and messages
The application passes relevant history and the current question in messages
Native features
Native multimodality and a one-million-token context window; focused on long-horizon programming and knowledge work
Native model features are for model selection; this platform's input limits, available parameters, and billing are subject to this model's API and pricing. Use stream for continuous Chat Completions output, and the client is responsible for saving message history.
Core Capabilities
Learn what kimi-k3 can bring to your work.
Continuous analysis around engineering constraints
K3 is suited to analyzing requirements, related code, error logs, and test conditions together, rather than merely generating isolated functions. You can ask it to first identify the scope of impact, then propose fixes and validation steps. Retaining file paths, dependencies, and non-modifiable conditions in the input helps produce engineering deliverables that are easier to review.
Turn visual references into implementation specifications
Combined with screenshots and written requirements, K3 can analyze page layouts, component hierarchies, and interaction intent, then generate interface code or redesign suggestions. It is suitable for starting frontend prototypes from visual references; you should also provide the technology stack, design guidelines, and responsive requirements to avoid asking the model to guess behaviors not shown in the screenshots.
Organize research and analysis into professional deliverables
Another focus of K3 is knowledge work: combining materials, data, and multi-round feedback to produce research reports, analytical explanations, or document drafts. Applications can provide real search and calculation results and ask the model to organize sources, conclusions, and items requiring confirmation separately; when further processing is needed, arrange the next steps based on these deliverables.
Use Cases
Start with specific tasks to find where the model can be effective.
Cross-file defect investigation
Provide the failure symptoms, relevant files, stack traces, and existing tests, and let K3 map the call chain, propose root-cause hypotheses, and deliver modification suggestions, patch drafts, and a regression test checklist. It is suitable for tasks that require linking multiple modules; feeding back actual test results can help it revise its initial assessment rather than stopping at a one-time guess.
Screenshot-driven frontend prototypes
Submit page screenshots, component specifications, and the target framework, and ask K3 to produce layout descriptions, component code, and interaction checklists. Then use browser screenshots to provide feedback on discrepancies and iteratively adjust spacing, hierarchy, and responsive behavior. The deliverable is prototype code that can be developed further; visual similarity alone should not be treated as passing functional and accessibility acceptance.
Preserve supporting materials for results
Keep the versions of materials submitted to kimi-k3 and the actual responses, distinguishing original facts, model suggestions, and actions already completed by the application. Before structured results enter the system, check required fields, value types, and business rules to avoid turning missing information directly into definitive records.
How to choose this model
Choose based on task complexity, input materials, and expected results.
Choose K3 for complex engineering; allocate routine tasks as needed
When a task requires multi-step analysis, contextual code understanding, or repeated use of tool results, K3 is a better fit. K2.6 and K2.5 can serve as alternatives for general conversation and content tasks. Do not directly reuse the Thinking toggle configuration from the K2 series; for short rewrites and simple extraction, compare delivery quality, response wait time, and actual usage before deciding.
Standard messages make it easy to integrate with existing applications
Use /v1/chat/completions and explicitly set model=kimi-k3. Existing OpenAI-compatible applications can retain their message and result handling; when integrating, configure the platform address, API Key, and exact model.
Getting started: revise using engineering context and interface references
Prepare the inputs first, then connect them to the appropriate application workflow.
Prepare inputs
Prepare the code structure, design screenshots, existing components, and acceptance requirements, and label image and text requirements separately.
Organize calls and follow-up workflows
Explicitly select kimi-k3 in the Chat Completions request, and organize the background, materials, and output requirements for this run into messages. First use a task with a clearly defined scope to check the response, then include real review or testing feedback in the next round of messages.
Practical task example: revise using engineering context and interface references
Design tasks directly from the following inputs and acceptance priorities.
Suggested task
Please analyze the differences between the screenshot and the existing page, propose a modification order by component, generate an implementation that preserves the API contract, and list acceptance items for desktop and mobile.
Key checks
After building the application, review the page item by item and verify the interface and interactions; tool execution and browser acceptance are completed by the integrated application environment.
Usage boundaries
Before formal use, understand the output quality and capability scope.
K3 continues reasoning, so treating disabled thinking as the default strategy for shortening responses is not suitable. For reasoning_effort, use max or omit it; do not rely on other values to obtain different speed tiers. Long tasks still require controlling the relevance of materials and setting a reasonable output budget for the final answer.
Image understanding is not the same as image generation, and converting screenshots to code does not mean the page has been run or verified. Blurry text, hidden interactions, and states outside the screenshot should be described separately; generated code needs to be tested in the target environment, especially for responsive layouts, keyboard operation, and business logic.
Multi-turn history is managed by the application through messages. After building the application, review the page item by item and verify the interface and interactions; tool execution and browser acceptance are completed by the integrated application environment.
Frequently Asked Questions
Answers to common questions about using kimi-k3.
Can Kimi K3 disable reasoning?
K3 keeps reasoning continuously enabled. Setting reasoning_effort: max is recommended, and it is used this way when omitted. Do not copy the K2.6 thinking switch into K3 requests. If the task is only brief rewriting or classification, consider a model better suited to lightweight tasks rather than relying on disabling reasoning.
Can K3 view screenshots and output web page code?
You can submit screenshots as image_url image blocks together with framework, style specifications, and interaction requirements for interface analysis and code generation. It outputs text code and suggestions; it does not automatically run the web page as a result. Verification should be completed through actual rendering, screenshot comparison, and interaction testing.
How do I call kimi-k3 using the standard API?
Submit model=kimi-k3 and messages to /v1/chat/completions. Read regular results from choices[].message.content; for streaming calls, obtain incremental results through stream. Use this platform's API Key and set the full base URL according to the SDK you use.
How can I make K3 return results that programs can process?
You can explicitly require JSON output in the prompt and specify field names, types, required fields, and allowed values, with examples; the application should perform JSON parsing, structural validation, and business validation, and set retries and exception handling for missing fields, type errors, or truncated results. If using response_format to configure the format, first verify the actual effect of the selected mode in kimi-k3 requests, and do not treat the json_schema field as a guarantee of strict Schema compliance.
How do I continue analysis from the previous turn?
Have the application save the message history and include the user and assistant messages relevant to the current question in messages. Prepare the code structure, design screenshots, existing components, and acceptance requirements, and label image and text requirements separately. When materials or constraints change, update them with the next request.