diff --git a/src/main/apiServer/app.ts b/src/main/apiServer/app.ts
index c52f4f85f1..786ca8b599 100644
--- a/src/main/apiServer/app.ts
+++ b/src/main/apiServer/app.ts
@@ -9,6 +9,7 @@ import { setupOpenAPIDocumentation } from './middleware/openapi'
 import { agentsRoutes } from './routes/agents'
 import { chatRoutes } from './routes/chat'
 import { mcpRoutes } from './routes/mcp'
+import { messagesRoutes } from './routes/messages'
 import { modelsRoutes } from './routes/models'
 
 const logger = loggerService.withContext('ApiServer')
@@ -114,6 +115,7 @@ apiRouter.use(express.json())
 // Mount routes
 apiRouter.use('/chat', chatRoutes)
 apiRouter.use('/mcps', mcpRoutes)
+apiRouter.use('/messages', messagesRoutes)
 apiRouter.use('/models', modelsRoutes)
 apiRouter.use('/agents', agentsRoutes)
 app.use('/v1', apiRouter)
diff --git a/src/main/apiServer/routes/messages.ts b/src/main/apiServer/routes/messages.ts
new file mode 100644
index 0000000000..fac281215a
--- /dev/null
+++ b/src/main/apiServer/routes/messages.ts
@@ -0,0 +1,272 @@
+import { MessageCreateParams } from '@anthropic-ai/sdk/resources'
+import express, { Request, Response } from 'express'
+
+import { loggerService } from '../../services/LoggerService'
+import { messagesService } from '../services/messages'
+import { validateModelId } from '../utils'
+
+const logger = loggerService.withContext('ApiServerMessagesRoutes')
+
+const router = express.Router()
+
+/**
+ * @swagger
+ * /v1/messages:
+ *   post:
+ *     summary: Create message
+ *     description: Create a message response using Anthropic's API format
+ *     tags: [Messages]
+ *     requestBody:
+ *       required: true
+ *       content:
+ *         application/json:
+ *           schema:
+ *             type: object
+ *             required:
+ *               - model
+ *               - max_tokens
+ *               - messages
+ *             properties:
+ *               model:
+ *                 type: string
+ *                 description: Model ID in format "provider:model_id"
+ *                 example: "my-anthropic:claude-3-5-sonnet-20241022"
+ *               max_tokens:
+ *                 type: integer
+ *                 minimum: 1
+ *                 description: Maximum number of tokens to generate
+ *                 example: 1024
+ *               messages:
+ *                 type: array
+ *                 items:
+ *                   type: object
+ *                   properties:
+ *                     role:
+ *                       type: string
+ *                       enum: [user, assistant]
+ *                     content:
+ *                       oneOf:
+ *                         - type: string
+ *                         - type: array
+ *               system:
+ *                 type: string
+ *                 description: System message
+ *               temperature:
+ *                 type: number
+ *                 minimum: 0
+ *                 maximum: 1
+ *                 description: Sampling temperature
+ *               top_p:
+ *                 type: number
+ *                 minimum: 0
+ *                 maximum: 1
+ *                 description: Nucleus sampling
+ *               top_k:
+ *                 type: integer
+ *                 minimum: 0
+ *                 description: Top-k sampling
+ *               stream:
+ *                 type: boolean
+ *                 description: Whether to stream the response
+ *               tools:
+ *                 type: array
+ *                 description: Available tools for the model
+ *     responses:
+ *       200:
+ *         description: Message response
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 id:
+ *                   type: string
+ *                 type:
+ *                   type: string
+ *                   example: message
+ *                 role:
+ *                   type: string
+ *                   example: assistant
+ *                 content:
+ *                   type: array
+ *                   items:
+ *                     type: object
+ *                 model:
+ *                   type: string
+ *                 stop_reason:
+ *                   type: string
+ *                 stop_sequence:
+ *                   type: string
+ *                 usage:
+ *                   type: object
+ *                   properties:
+ *                     input_tokens:
+ *                       type: integer
+ *                     output_tokens:
+ *                       type: integer
+ *           text/plain:
+ *             schema:
+ *               type: string
+ *               description: Server-sent events stream (when stream=true)
+ *       400:
+ *         description: Bad request
+ *         content:
+ *           application/json:
+ *             schema:
+ *               type: object
+ *               properties:
+ *                 type:
+ *                   type: string
+ *                   example: error
+ *                 error:
+ *                   type: object
+ *                   properties:
+ *                     type:
+ *                       type: string
+ *                     message:
+ *                       type: string
+ *       401:
+ *         description: Unauthorized
+ *       429:
+ *         description: Rate limit exceeded
+ *       500:
+ *         description: Internal server error
+ */
+router.post('/', async (req: Request, res: Response) => {
+  try {
+    const request: MessageCreateParams = req.body
+
+    if (!request) {
+      return res.status(400).json({
+        type: 'error',
+        error: {
+          type: 'invalid_request_error',
+          message: 'Request body is required'
+        }
+      })
+    }
+
+    logger.info('Anthropic message request:', {
+      model: request.model,
+      messageCount: request.messages?.length || 0,
+      stream: request.stream,
+      max_tokens: request.max_tokens,
+      temperature: request.temperature
+    })
+
+    // Validate request
+    const validation = messagesService.validateRequest(request)
+    if (!validation.isValid) {
+      return res.status(400).json({
+        type: 'error',
+        error: {
+          type: 'invalid_request_error',
+          message: validation.errors.join('; ')
+        }
+      })
+    }
+
+    // Validate model ID and get provider
+    const modelValidation = await validateModelId(request.model)
+    if (!modelValidation.valid) {
+      const error = modelValidation.error!
+      logger.warn(`Model validation failed for '${request.model}':`, error)
+      return res.status(400).json({
+        type: 'error',
+        error: {
+          type: 'invalid_request_error',
+          message: error.message
+        }
+      })
+    }
+
+    const provider = modelValidation.provider!
+
+    // Ensure provider is Anthropic type
+    if (provider.type !== 'anthropic') {
+      return res.status(400).json({
+        type: 'error',
+        error: {
+          type: 'invalid_request_error',
+          message: `Invalid provider type '${provider.type}' for messages endpoint. Expected 'anthropic' provider.`
+        }
+      })
+    }
+
+    const modelId = modelValidation.modelId!
+    request.model = modelId
+
+    logger.info('Model validation successful:', {
+      provider: provider.id,
+      providerType: provider.type,
+      modelId: modelId,
+      fullModelId: request.model
+    })
+
+    // Handle streaming
+    if (request.stream) {
+      res.setHeader('Content-Type', 'text/plain; charset=utf-8')
+      res.setHeader('Cache-Control', 'no-cache')
+      res.setHeader('Connection', 'keep-alive')
+
+      try {
+        for await (const chunk of messagesService.processStreamingMessage(request, provider)) {
+          res.write(`data: ${JSON.stringify(chunk)}\n\n`)
+        }
+        res.write('data: [DONE]\n\n')
+        res.end()
+      } catch (streamError: any) {
+        logger.error('Stream error:', streamError)
+        res.write(
+          `data: ${JSON.stringify({
+            type: 'error',
+            error: {
+              type: 'api_error',
+              message: 'Stream processing error'
+            }
+          })}\n\n`
+        )
+        res.end()
+      }
+      return
+    }
+
+    // Handle non-streaming
+    const response = await messagesService.processMessage(request, provider)
+    return res.json(response)
+  } catch (error: any) {
+    logger.error('Anthropic message error:', error)
+
+    let statusCode = 500
+    let errorType = 'api_error'
+    let errorMessage = 'Internal server error'
+
+    if (error instanceof Error) {
+      errorMessage = error.message
+
+      if (error.message.includes('API key') || error.message.includes('authentication')) {
+        statusCode = 401
+        errorType = 'authentication_error'
+      } else if (error.message.includes('rate limit') || error.message.includes('quota')) {
+        statusCode = 429
+        errorType = 'rate_limit_error'
+      } else if (error.message.includes('timeout') || error.message.includes('connection')) {
+        statusCode = 502
+        errorType = 'api_error'
+      } else if (error.message.includes('validation') || error.message.includes('invalid')) {
+        statusCode = 400
+        errorType = 'invalid_request_error'
+      }
+    }
+
+    return res.status(statusCode).json({
+      type: 'error',
+      error: {
+        type: errorType,
+        message: errorMessage
+      }
+    })
+  }
+})
+
+export { router as messagesRoutes }
diff --git a/src/main/apiServer/services/messages.ts b/src/main/apiServer/services/messages.ts
new file mode 100644
index 0000000000..a845218802
--- /dev/null
+++ b/src/main/apiServer/services/messages.ts
@@ -0,0 +1,120 @@
+import Anthropic from '@anthropic-ai/sdk'
+import { Message, MessageCreateParams, RawMessageStreamEvent } from '@anthropic-ai/sdk/resources'
+import { Provider } from '@types'
+
+import { loggerService } from '../../services/LoggerService'
+
+const logger = loggerService.withContext('MessagesService')
+
+export interface ValidationResult {
+  isValid: boolean
+  errors: string[]
+}
+
+export class MessagesService {
+  // oxlint-disable-next-line no-unused-vars
+  validateRequest(request: MessageCreateParams): ValidationResult {
+    // TODO: Implement comprehensive request validation
+    const errors: string[] = []
+
+    if (!request.model) {
+      errors.push('Model is required')
+    }
+
+    return {
+      isValid: errors.length === 0,
+      errors
+    }
+  }
+
+  async processMessage(request: MessageCreateParams, provider: Provider): Promise<Message> {
+    try {
+      logger.info('Processing Anthropic message request:', {
+        model: request.model,
+        messageCount: request.messages.length,
+        stream: request.stream,
+        max_tokens: request.max_tokens
+      })
+
+      // Validate request
+      const validation = this.validateRequest(request)
+      if (!validation.isValid) {
+        throw new Error(`Request validation failed: ${validation.errors.join(', ')}`)
+      }
+
+      // Create Anthropic client for the provider
+      const client = new Anthropic({
+        baseURL: provider.apiHost,
+        apiKey: provider.apiKey
+      })
+
+      // Prepare request with the actual model ID
+      const anthropicRequest: MessageCreateParams = {
+        ...request,
+        stream: false
+      }
+
+      logger.debug('Sending request to Anthropic provider:', {
+        provider: provider.id,
+        apiHost: provider.apiHost
+      })
+
+      const response = await client.messages.create(anthropicRequest)
+
+      logger.info('Successfully processed Anthropic message')
+      return response
+    } catch (error: any) {
+      logger.error('Error processing Anthropic message:', error)
+      throw error
+    }
+  }
+
+  async *processStreamingMessage(
+    request: MessageCreateParams,
+    provider: Provider
+  ): AsyncIterable<RawMessageStreamEvent> {
+    try {
+      logger.info('Processing streaming Anthropic message request:', {
+        model: request.model,
+        messageCount: request.messages.length
+      })
+
+      // Validate request
+      const validation = this.validateRequest(request)
+      if (!validation.isValid) {
+        throw new Error(`Request validation failed: ${validation.errors.join(', ')}`)
+      }
+
+      // Create Anthropic client for the provider
+      const client = new Anthropic({
+        baseURL: provider.apiHost,
+        apiKey: provider.apiKey
+      })
+
+      // Prepare streaming request
+      const streamingRequest: MessageCreateParams = {
+        ...request,
+        stream: true
+      }
+
+      logger.debug('Sending streaming request to Anthropic provider:', {
+        provider: provider.id,
+        apiHost: provider.apiHost
+      })
+
+      const stream = client.messages.stream(streamingRequest)
+
+      for await (const chunk of stream) {
+        yield chunk
+      }
+
+      logger.info('Successfully completed streaming Anthropic message')
+    } catch (error: any) {
+      logger.error('Error processing streaming Anthropic message:', error)
+      throw error
+    }
+  }
+}
+
+// Export singleton instance
+export const messagesService = new MessagesService()
diff --git a/src/main/apiServer/utils/index.ts b/src/main/apiServer/utils/index.ts
index 9d3b81c328..9b198325c5 100644
--- a/src/main/apiServer/utils/index.ts
+++ b/src/main/apiServer/utils/index.ts
@@ -23,12 +23,12 @@ export async function getAvailableProviders(): Promise<Provider[]> {
       return []
     }
 
-    // Only support OpenAI type providers for API server
-    const openAIProviders = providers.filter((p: Provider) => p.enabled && p.type === 'openai')
+    // Support OpenAI and Anthropic type providers for API server
+    const supportedProviders = providers.filter((p: Provider) => p.enabled && (p.type === 'openai' || p.type === 'anthropic'))
 
-    logger.info(`Filtered to ${openAIProviders.length} OpenAI providers from ${providers.length} total providers`)
+    logger.info(`Filtered to ${supportedProviders.length} supported providers from ${providers.length} total providers`)
 
-    return openAIProviders
+    return supportedProviders
   } catch (error: any) {
     logger.error('Failed to get providers from Redux store:', error)
     return []
@@ -215,10 +215,10 @@ export function validateProvider(provider: Provider): boolean {
       return false
     }
 
-    // Only support OpenAI type providers
-    if (provider.type !== 'openai') {
+    // Support OpenAI and Anthropic type providers
+    if (provider.type !== 'openai' && provider.type !== 'anthropic') {
       logger.debug(
-        `Provider type '${provider.type}' not supported, only 'openai' type is currently supported: ${provider.id}`
+        `Provider type '${provider.type}' not supported, only 'openai' and 'anthropic' types are currently supported: ${provider.id}`
       )
       return false
     }