> ## Documentation Index > Fetch the complete documentation index at: https://docs.morphllm.com/llms.txt > Use this file to discover all available pages before exploring further. # Apply API > Apply code edits at 10,500 tok/s with 98% accuracy via OpenAI-compatible API ## Overview The Apply API enables lightning-fast code editing at **10,500+ tokens/second** with **98% accuracy**. This OpenAI-compatible endpoint intelligently merges code changes while preserving structure and formatting. ## Models Choose the model that best fits your use case: Model Speed Accuracy Best For morph-v3-fast 10,500+ tok/sec 96% Real-time applications, quick edits morph-v3-large 5000+ tok/sec 98% Complex changes, highest accuracy auto 5000-10,500tok/sec \~98% Recommended - automatically selects optimal model

## Message Format The Apply API uses a structured XML format within the message content: ``` Brief description of what you're changing Original code content Code snippet showing only the changes with // ... existing code ... markers ``` ### Format Guidelines * **``**: Optional but recommended. Use first-person, clear descriptions * **`

`**: The complete original code that needs modification
* **``**: Show only what changes, using `// ... existing code ...` for unchanged sections

## Usage Examples


  ```typescript TypeScript highlight={13} theme={null}
  import OpenAI from "openai";

  const openai = new OpenAI({
    apiKey: "YOUR_API_KEY",
    baseURL: "https://api.morphllm.com/v1",
  });

  const instruction = "I will add error handling to prevent division by zero";
  const originalCode = "function divide(a, b) {\n  return a / b;\n}";
  const codeEdit = "function divide(a, b) {\n  if (b === 0) {\n    throw new Error('Cannot divide by zero');\n  }\n  return a / b;\n}";

  const response = await openai.chat.completions.create({
    model: "morph-v3-fast",
    messages: [
      {
        role: "user",
        content: `${instruction}\n${originalCode}\n${codeEdit}`,
      },
    ],
  });

  const mergedCode = response.choices[0].message.content;
  ```

  ```python Python highlight={14} theme={null}
  import os
  from openai import OpenAI

  client = OpenAI(
      api_key="YOUR_API_KEY",
      base_url="https://api.morphllm.com/v1"
  )

  instruction = "I will add error handling to prevent division by zero"
  original_code = "function divide(a, b) {\n  return a / b;\n}"
  code_edit = "function divide(a, b) {\n  if (b === 0) {\n    throw new Error('Cannot divide by zero');\n  }\n  return a / b;\n}"

  response = client.chat.completions.create(
      model="morph-v3-fast",
      messages=[
          {
              "role": "user",
              "content": f"{instruction}\n{original_code}\n{code_edit}"
          }
      ]
  )

  merged_code = response.choices[0].message.content
  ```

  ```bash cURL highlight={9} theme={null}
  curl -X POST "https://api.morphllm.com/v1/chat/completions" \
    -H "Authorization: Bearer YOUR_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "morph-v3-fast",
      "messages": [
        {
          "role": "user",
          "content": "I will add error handling to prevent division by zero\nfunction divide(a, b) {\n  return a / b;\n}\nfunction divide(a, b) {\n  if (b === 0) {\n    throw new Error(\"Cannot divide by zero\");\n  }\n  return a / b;\n}"
        }
      ]
    }'
  ```


## Error Codes


    
      HTTP Status
      Description
    
  
    
      
        200
      

      Success - chat completion response
    

    
      
        400
      

      Bad request - malformed request or parameters
    

    
      
        401
      

      Authentication error - invalid API key
    
  
  

  



  
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