diff --git a/src/routes/activity.ts b/src/routes/activity.ts
new file mode 100644
index 0000000..be8eec4
--- /dev/null
+++ b/src/routes/activity.ts
@@ -0,0 +1,265 @@
+import type { FastifyPluginAsyncZod } from 'fastify-type-provider-zod'
+import { z } from 'zod'
+import { authMiddleware } from '@/middlewares/auth.middleware'
+import { ActivityService } from '@/services/activity.service'
+import {
+  createResponseSchema,
+  ErrorCode,
+  errorResponse,
+  errorResponseSchema,
+  successResponse,
+} from '@/types/response'
+
+// Schema for request parameters
+const repoParamsSchema = z.object({
+  owner: z.string(),
+  repo: z.string(),
+})
+
+// Schema for query parameters
+const activityQuerySchema = z.object({
+  state: z.enum(['open', 'closed', 'all']).optional().default('all'),
+  per_page: z.coerce.number().min(1).max(100).optional().default(30),
+})
+
+const commitsQuerySchema = z.object({
+  per_page: z.coerce.number().min(1).max(100).optional().default(30),
+})
+
+// Activity timeline schemas
+const commitActivitySchema = z.object({
+  sha: z.string(),
+  message: z.string(),
+  author: z.object({
+    name: z.string(),
+    email: z.string(),
+    date: z.string(),
+    avatar: z.string().optional(),
+  }),
+  committer: z.object({
+    name: z.string(),
+    date: z.string(),
+  }),
+  url: z.string(),
+})
+
+const pullRequestActivitySchema = z.object({
+  number: z.number(),
+  title: z.string(),
+  state: z.string(),
+  user: z.object({
+    login: z.string(),
+    avatar_url: z.string(),
+  }),
+  created_at: z.string(),
+  updated_at: z.string(),
+  merged_at: z.string().nullable(),
+  html_url: z.string(),
+})
+
+const issueActivitySchema = z.object({
+  number: z.number(),
+  title: z.string(),
+  state: z.string(),
+  user: z.object({
+    login: z.string(),
+    avatar_url: z.string(),
+  }),
+  created_at: z.string(),
+  updated_at: z.string(),
+  closed_at: z.string().nullable(),
+  html_url: z.string(),
+  labels: z
+    .object({
+      name: z.string(),
+      color: z.string(),
+    })
+    .array(),
+})
+
+const commitActivityStatsSchema = z.object({
+  days: z.number().array(),
+  total: z.number(),
+  week: z.number(),
+})
+
+const contributorStatsSchema = z.object({
+  author: z.object({
+    login: z.string(),
+    avatar_url: z.string(),
+  }),
+  total: z.number(),
+  weeks: z
+    .object({
+      w: z.number(),
+      a: z.number(),
+      d: z.number(),
+      c: z.number(),
+    })
+    .array(),
+})
+
+// Response schemas
+const commitsResponseSchema = createResponseSchema(commitActivitySchema.array())
+const pullRequestsResponseSchema = createResponseSchema(pullRequestActivitySchema.array())
+const issuesResponseSchema = createResponseSchema(issueActivitySchema.array())
+const commitActivityStatsResponseSchema = createResponseSchema(commitActivityStatsSchema.array())
+const contributorStatsResponseSchema = createResponseSchema(contributorStatsSchema.array())
+
+export const activityRoutes: FastifyPluginAsyncZod = async (app) => {
+  // All routes in this plugin require authentication
+  app.addHook('preHandler', authMiddleware)
+
+  // Route to get recent commits
+  app.get(
+    '/:owner/:repo/commits',
+    {
+      schema: {
+        description: 'Get recent commits for activity timeline',
+        tags: ['activity'],
+        params: repoParamsSchema,
+        querystring: commitsQuerySchema,
+        response: {
+          200: commitsResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { per_page } = request.query
+        const { accessToken, username } = request.user
+        const activityService = new ActivityService(accessToken, username)
+        const commits = await activityService.getRecentCommits(owner, repo, per_page)
+        return successResponse(commits)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch commits'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get recent pull requests
+  app.get(
+    '/:owner/:repo/pulls',
+    {
+      schema: {
+        description: 'Get recent pull requests for activity timeline',
+        tags: ['activity'],
+        params: repoParamsSchema,
+        querystring: activityQuerySchema,
+        response: {
+          200: pullRequestsResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { state, per_page } = request.query
+        const { accessToken, username } = request.user
+        const activityService = new ActivityService(accessToken, username)
+        const pulls = await activityService.getRecentPullRequests(owner, repo, state, per_page)
+        return successResponse(pulls)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch pull requests'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get recent issues
+  app.get(
+    '/:owner/:repo/issues',
+    {
+      schema: {
+        description: 'Get recent issues for activity timeline (excludes PRs)',
+        tags: ['activity'],
+        params: repoParamsSchema,
+        querystring: activityQuerySchema,
+        response: {
+          200: issuesResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { state, per_page } = request.query
+        const { accessToken, username } = request.user
+        const activityService = new ActivityService(accessToken, username)
+        const issues = await activityService.getRecentIssues(owner, repo, state, per_page)
+        return successResponse(issues)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch issues'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get commit activity stats (heatmap data)
+  app.get(
+    '/:owner/:repo/commit-stats',
+    {
+      schema: {
+        description:
+          'Get commit activity statistics (weekly) for heatmap. ⚠️ Only for repos with <10k commits',
+        tags: ['activity'],
+        params: repoParamsSchema,
+        response: {
+          200: commitActivityStatsResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { accessToken, username } = request.user
+        const activityService = new ActivityService(accessToken, username)
+        const stats = await activityService.getCommitActivityStats(owner, repo)
+        return successResponse(stats)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch commit activity stats'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get contributor statistics
+  app.get(
+    '/:owner/:repo/contributors',
+    {
+      schema: {
+        description:
+          'Get contributor statistics with weekly breakdown. ⚠️ Only for repos with <10k commits',
+        tags: ['activity'],
+        params: repoParamsSchema,
+        response: {
+          200: contributorStatsResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { accessToken, username } = request.user
+        const activityService = new ActivityService(accessToken, username)
+        const stats = await activityService.getContributorStats(owner, repo)
+        return successResponse(stats)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch contributor stats'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+}
diff --git a/src/routes/code-stats.ts b/src/routes/code-stats.ts
new file mode 100644
index 0000000..b400bcb
--- /dev/null
+++ b/src/routes/code-stats.ts
@@ -0,0 +1,234 @@
+import type { FastifyPluginAsyncZod } from 'fastify-type-provider-zod'
+import { z } from 'zod'
+import { authMiddleware } from '@/middlewares/auth.middleware'
+import { CodeStatsService } from '@/services/code-stats.service'
+import {
+  createResponseSchema,
+  ErrorCode,
+  errorResponse,
+  errorResponseSchema,
+  successResponse,
+} from '@/types/response'
+
+// Schema for request parameters
+const repoParamsSchema = z.object({
+  owner: z.string(),
+  repo: z.string(),
+})
+
+// Query schemas
+const fileTreeQuerySchema = z.object({
+  branch: z.string().optional().default('main'),
+  recursive: z.coerce.boolean().optional().default(true),
+})
+
+const hotFilesQuerySchema = z.object({
+  limit: z.coerce.number().min(10).max(200).optional().default(100),
+  top: z.coerce.number().min(5).max(50).optional().default(20),
+})
+
+const fileStructureQuerySchema = z.object({
+  branch: z.string().optional().default('main'),
+})
+
+// Response schemas
+const languageStatsSchema = z.record(z.string(), z.number())
+
+const codeFrequencySchema = z.object({
+  week: z.number(),
+  additions: z.number(),
+  deletions: z.number(),
+})
+
+const fileTreeSchema = z.object({
+  path: z.string(),
+  mode: z.string(),
+  type: z.enum(['blob', 'tree']),
+  sha: z.string(),
+  size: z.number().optional(),
+  url: z.string().optional(),
+})
+
+const hotFileSchema = z.object({
+  path: z.string(),
+  changeCount: z.number(),
+  lastModified: z.string(),
+  authors: z.string().array(),
+})
+
+const fileStructureSummarySchema = z.object({
+  totalFiles: z.number(),
+  totalDirectories: z.number(),
+  totalSize: z.number(),
+  filesByExtension: z.record(z.string(), z.number()),
+  largestFiles: z
+    .object({
+      path: z.string(),
+      size: z.number(),
+    })
+    .array(),
+})
+
+// Response schemas with unified format
+const languageStatsResponseSchema = createResponseSchema(languageStatsSchema)
+const codeFrequencyResponseSchema = createResponseSchema(codeFrequencySchema.array())
+const fileTreeResponseSchema = createResponseSchema(fileTreeSchema.array())
+const hotFilesResponseSchema = createResponseSchema(hotFileSchema.array())
+const fileStructureSummaryResponseSchema = createResponseSchema(fileStructureSummarySchema)
+
+export const codeStatsRoutes: FastifyPluginAsyncZod = async (app) => {
+  // All routes in this plugin require authentication
+  app.addHook('preHandler', authMiddleware)
+
+  // Route to get language distribution
+  app.get(
+    '/:owner/:repo/languages',
+    {
+      schema: {
+        description: 'Get programming language distribution (in bytes)',
+        tags: ['code-stats'],
+        params: repoParamsSchema,
+        response: {
+          200: languageStatsResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { accessToken, username } = request.user
+        const codeStatsService = new CodeStatsService(accessToken, username)
+        const languages = await codeStatsService.getLanguageStats(owner, repo)
+        return successResponse(languages)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch language statistics'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get code frequency (weekly additions/deletions)
+  app.get(
+    '/:owner/:repo/code-frequency',
+    {
+      schema: {
+        description:
+          'Get code frequency statistics (weekly additions/deletions). ⚠️ Only for repos with <10k commits',
+        tags: ['code-stats'],
+        params: repoParamsSchema,
+        response: {
+          200: codeFrequencyResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { accessToken, username } = request.user
+        const codeStatsService = new CodeStatsService(accessToken, username)
+        const frequency = await codeStatsService.getCodeFrequency(owner, repo)
+        return successResponse(frequency)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch code frequency'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get file tree structure
+  app.get(
+    '/:owner/:repo/file-tree',
+    {
+      schema: {
+        description: 'Get repository file tree structure',
+        tags: ['code-stats'],
+        params: repoParamsSchema,
+        querystring: fileTreeQuerySchema,
+        response: {
+          200: fileTreeResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { branch, recursive } = request.query
+        const { accessToken, username } = request.user
+        const codeStatsService = new CodeStatsService(accessToken, username)
+        const fileTree = await codeStatsService.getFileTree(owner, repo, branch, recursive)
+        return successResponse(fileTree)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch file tree'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get hot files (most frequently modified)
+  app.get(
+    '/:owner/:repo/hot-files',
+    {
+      schema: {
+        description: 'Get hot files (most frequently modified files) by analyzing recent commits',
+        tags: ['code-stats'],
+        params: repoParamsSchema,
+        querystring: hotFilesQuerySchema,
+        response: {
+          200: hotFilesResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { limit, top } = request.query
+        const { accessToken, username } = request.user
+        const codeStatsService = new CodeStatsService(accessToken, username)
+        const hotFiles = await codeStatsService.getHotFiles(owner, repo, limit, top)
+        return successResponse(hotFiles)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to analyze hot files'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+
+  // Route to get file structure summary
+  app.get(
+    '/:owner/:repo/file-structure-summary',
+    {
+      schema: {
+        description: 'Get file structure summary (counts by type, largest files, etc.)',
+        tags: ['code-stats'],
+        params: repoParamsSchema,
+        querystring: fileStructureQuerySchema,
+        response: {
+          200: fileStructureSummaryResponseSchema,
+          500: errorResponseSchema,
+        },
+      },
+    },
+    async (request, reply) => {
+      try {
+        const { owner, repo } = request.params
+        const { branch } = request.query
+        const { accessToken, username } = request.user
+        const codeStatsService = new CodeStatsService(accessToken, username)
+        const summary = await codeStatsService.getFileStructureSummary(owner, repo, branch)
+        return successResponse(summary)
+      } catch (err) {
+        const error = err as Error
+        const errorMessage = error.message || 'Failed to fetch file structure summary'
+        return reply.status(500).send(errorResponse(ErrorCode.GITHUB_API_ERROR, errorMessage))
+      }
+    }
+  )
+}
diff --git a/src/routes/repos.ts b/src/routes/repos.ts
index 33a9c0a..c06312d 100644
--- a/src/routes/repos.ts
+++ b/src/routes/repos.ts
@@ -46,7 +46,7 @@ const repoOverviewSchema = z.object({
   size: z.number(),
   language: z.string().nullable(),
   languages: z.record(z.string(), z.number()).nullable(),
-  topics: z.array(z.string()),
+  topics: z.string().array(),
   licenseName: z.string().nullable(),
   licenseKey: z.string().nullable(),
   githubCreatedAt: z.date(),
@@ -81,7 +81,7 @@ const repoListItemSchema = z.object({
   }),
 })
 
-const reposListSchema = z.array(repoListItemSchema)
+const reposListSchema = repoListItemSchema.array()
 
 // Use the unified response format
 const reposListResponseSchema = createResponseSchema(reposListSchema)
diff --git a/src/server.ts b/src/server.ts
index 3bc65e1..45e1696 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -11,6 +11,8 @@ import 'dotenv/config'
 
 import { authRoutes } from '@/routes/auth'
 import { repoRoutes } from '@/routes/repos'
+import { activityRoutes } from '@/routes/activity'
+import { codeStatsRoutes } from '@/routes/code-stats'
 import { statsRoutes } from '@/routes/stats'
 import { webhookRoutes } from '@/routes/webhooks'
 import { ErrorCode, errorResponse } from '@/types/response'
@@ -117,6 +119,14 @@ GitHub API rate limits apply. Authenticated requests: 5,000/hour.
           name: 'repos',
           description: 'Repository management and statistics',
         },
+        {
+          name: 'activity',
+          description: 'Repository activity timeline (commits, PRs, issues)',
+        },
+        {
+          name: 'code-stats',
+          description: 'Code statistics and analysis (languages, file structure, hot files)',
+        },
         {
           name: 'stats',
           description: 'User statistics and analytics',
@@ -175,6 +185,8 @@ GitHub API rate limits apply. Authenticated requests: 5,000/hour.
   // Register routes
   await app.register(authRoutes, { prefix: '/auth' })
   await app.register(repoRoutes, { prefix: '/repos' })
+  await app.register(activityRoutes, { prefix: '/activity' })
+  await app.register(codeStatsRoutes, { prefix: '/code-stats' })
   await app.register(statsRoutes, { prefix: '/stats' })
   await app.register(webhookRoutes, { prefix: '/webhooks' })
 
diff --git a/src/services/activity.service.ts b/src/services/activity.service.ts
new file mode 100644
index 0000000..d9041a4
--- /dev/null
+++ b/src/services/activity.service.ts
@@ -0,0 +1,351 @@
+import { Octokit } from '@octokit/rest'
+import { redis } from '@/lib/redis'
+
+// Activity timeline types
+export interface CommitActivity {
+  sha: string
+  message: string
+  author: {
+    name: string
+    email: string
+    date: string
+    avatar?: string
+  }
+  committer: {
+    name: string
+    date: string
+  }
+  url: string
+}
+
+export interface PullRequestActivity {
+  number: number
+  title: string
+  state: string
+  user: {
+    login: string
+    avatar_url: string
+  }
+  created_at: string
+  updated_at: string
+  merged_at: string | null
+  html_url: string
+}
+
+export interface IssueActivity {
+  number: number
+  title: string
+  state: string
+  user: {
+    login: string
+    avatar_url: string
+  }
+  created_at: string
+  updated_at: string
+  closed_at: string | null
+  html_url: string
+  labels: {
+    name: string
+    color: string
+  }[]
+}
+
+export interface CommitActivityStats {
+  days: number[] // 7 days, 0 = Sunday
+  total: number
+  week: number // Unix timestamp
+}
+
+export interface ContributorStats {
+  author: {
+    login: string
+    avatar_url: string
+  }
+  total: number
+  weeks: {
+    w: number // Week timestamp
+    a: number // Additions
+    d: number // Deletions
+    c: number // Commits
+  }[]
+}
+
+export class ActivityService {
+  private octokit: Octokit
+
+  constructor(accessToken: string, _username: string) {
+    this.octokit = new Octokit({ auth: accessToken })
+  }
+
+  /**
+   * Get recent commits for activity timeline
+   */
+  async getRecentCommits(owner: string, repo: string, per_page = 30): Promise<CommitActivity[]> {
+    const cacheKey = `repo:commits:${owner}/${repo}:${String(per_page)}`
+    const CACHE_TTL = 300 // 5 minutes
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as CommitActivity[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    const { data } = await this.octokit.repos.listCommits({
+      owner,
+      repo,
+      per_page,
+    })
+
+    const commits: CommitActivity[] = data.map((commit) => ({
+      sha: commit.sha,
+      message: commit.commit.message,
+      author: {
+        name: commit.commit.author?.name ?? 'Unknown',
+        email: commit.commit.author?.email ?? '',
+        date: commit.commit.author?.date ?? '',
+        avatar: commit.author?.avatar_url,
+      },
+      committer: {
+        name: commit.commit.committer?.name ?? 'Unknown',
+        date: commit.commit.committer?.date ?? '',
+      },
+      url: commit.html_url,
+    }))
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(commits), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache commits:', error)
+    }
+
+    return commits
+  }
+
+  /**
+   * Get recent pull requests for activity timeline
+   */
+  async getRecentPullRequests(
+    owner: string,
+    repo: string,
+    state: 'open' | 'closed' | 'all' = 'all',
+    per_page = 30
+  ): Promise<PullRequestActivity[]> {
+    const cacheKey = `repo:prs:${owner}/${repo}:${state}:${String(per_page)}`
+    const CACHE_TTL = 300 // 5 minutes
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as PullRequestActivity[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    const { data } = await this.octokit.pulls.list({
+      owner,
+      repo,
+      state,
+      per_page,
+      sort: 'updated',
+      direction: 'desc',
+    })
+
+    const pullRequests: PullRequestActivity[] = data.map((pr) => ({
+      number: pr.number,
+      title: pr.title,
+      state: pr.state,
+      user: {
+        login: pr.user?.login ?? 'Unknown',
+        avatar_url: pr.user?.avatar_url ?? '',
+      },
+      created_at: pr.created_at,
+      updated_at: pr.updated_at,
+      merged_at: pr.merged_at,
+      html_url: pr.html_url,
+    }))
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(pullRequests), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache pull requests:', error)
+    }
+
+    return pullRequests
+  }
+
+  /**
+   * Get recent issues for activity timeline
+   */
+  async getRecentIssues(
+    owner: string,
+    repo: string,
+    state: 'open' | 'closed' | 'all' = 'all',
+    per_page = 30
+  ): Promise<IssueActivity[]> {
+    const cacheKey = `repo:issues:${owner}/${repo}:${state}:${String(per_page)}`
+    const CACHE_TTL = 300 // 5 minutes
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as IssueActivity[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    const { data } = await this.octokit.issues.listForRepo({
+      owner,
+      repo,
+      state,
+      per_page,
+      sort: 'updated',
+      direction: 'desc',
+    })
+
+    // Filter out pull requests (GitHub API returns both issues and PRs)
+    const issues: IssueActivity[] = data
+      .filter((issue) => !issue.pull_request)
+      .map((issue) => ({
+        number: issue.number,
+        title: issue.title,
+        state: issue.state,
+        user: {
+          login: issue.user?.login ?? 'Unknown',
+          avatar_url: issue.user?.avatar_url ?? '',
+        },
+        created_at: issue.created_at,
+        updated_at: issue.updated_at,
+        closed_at: issue.closed_at,
+        html_url: issue.html_url,
+        labels: issue.labels.map((label) => ({
+          name: typeof label === 'string' ? label : (label.name ?? ''),
+          color: typeof label === 'string' ? '' : (label.color ?? ''),
+        })),
+      }))
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(issues), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache issues:', error)
+    }
+
+    return issues
+  }
+
+  /**
+   * Get commit activity statistics (weekly commit activity)
+   * ⚠️ Only available for repositories with < 10,000 commits
+   * ⚠️ First request returns 202, need to retry
+   */
+  async getCommitActivityStats(owner: string, repo: string): Promise<CommitActivityStats[]> {
+    const cacheKey = `repo:commit-activity:${owner}/${repo}`
+    const CACHE_TTL = 3600 // 1 hour (GitHub caches this data)
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as CommitActivityStats[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    // GitHub returns 202 on first request, need to retry
+    const maxRetries = 3
+    for (let retry = 0; retry < maxRetries; retry++) {
+      try {
+        const response = await this.octokit.repos.getCommitActivityStats({ owner, repo })
+
+        if (response.status === 200 && response.data.length > 0) {
+          const stats = response.data as CommitActivityStats[]
+
+          try {
+            await redis.set(cacheKey, JSON.stringify(stats), { ex: CACHE_TTL })
+          } catch (error) {
+            console.warn('Failed to cache commit activity stats:', error)
+          }
+
+          return stats
+        }
+
+        // If 202, wait and retry
+        if (response.status === 202 && retry < maxRetries - 1) {
+          await new Promise((resolve) => setTimeout(resolve, 2000))
+          continue
+        }
+      } catch (error) {
+        console.error('Error fetching commit activity stats:', error)
+        throw error
+      }
+    }
+
+    throw new Error('Failed to fetch commit activity stats after retries')
+  }
+
+  /**
+   * Get contributor statistics
+   * ⚠️ Only available for repositories with < 10,000 commits
+   * ⚠️ First request returns 202, need to retry
+   */
+  async getContributorStats(owner: string, repo: string): Promise<ContributorStats[]> {
+    const cacheKey = `repo:contributor-stats:${owner}/${repo}`
+    const CACHE_TTL = 3600 // 1 hour (GitHub caches this data)
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as ContributorStats[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    // GitHub returns 202 on first request, need to retry
+    const maxRetries = 3
+    for (let retry = 0; retry < maxRetries; retry++) {
+      try {
+        const response = await this.octokit.repos.getContributorsStats({ owner, repo })
+
+        if (response.status === 200 && response.data.length > 0) {
+          const stats: ContributorStats[] = response.data.map((contributor) => ({
+            author: {
+              login: contributor.author?.login ?? 'Unknown',
+              avatar_url: contributor.author?.avatar_url ?? '',
+            },
+            total: contributor.total,
+            weeks: contributor.weeks.map((week) => ({
+              w: week.w ?? 0,
+              a: week.a ?? 0,
+              d: week.d ?? 0,
+              c: week.c ?? 0,
+            })),
+          }))
+
+          try {
+            await redis.set(cacheKey, JSON.stringify(stats), { ex: CACHE_TTL })
+          } catch (error) {
+            console.warn('Failed to cache contributor stats:', error)
+          }
+
+          return stats
+        }
+
+        // If 202, wait and retry
+        if (response.status === 202 && retry < maxRetries - 1) {
+          await new Promise((resolve) => setTimeout(resolve, 2000))
+          continue
+        }
+      } catch (error) {
+        console.error('Error fetching contributor stats:', error)
+        throw error
+      }
+    }
+
+    throw new Error('Failed to fetch contributor stats after retries')
+  }
+}
diff --git a/src/services/code-stats.service.ts b/src/services/code-stats.service.ts
new file mode 100644
index 0000000..9368a09
--- /dev/null
+++ b/src/services/code-stats.service.ts
@@ -0,0 +1,365 @@
+import { Octokit } from '@octokit/rest'
+import { redis } from '@/lib/redis'
+
+// Language distribution
+export type LanguageStats = Record<string, number> // bytes of code
+
+// Code frequency (weekly additions/deletions)
+export interface CodeFrequency {
+  week: number // Unix timestamp
+  additions: number
+  deletions: number
+}
+
+// File tree structure
+export interface FileTree {
+  path: string
+  mode: string
+  type: 'blob' | 'tree'
+  sha: string
+  size?: number
+  url?: string
+}
+
+// Hot files (most frequently modified)
+export interface HotFile {
+  path: string
+  changeCount: number
+  lastModified: string
+  authors: string[]
+}
+
+export class CodeStatsService {
+  private octokit: Octokit
+
+  constructor(accessToken: string, _username: string) {
+    this.octokit = new Octokit({ auth: accessToken })
+  }
+
+  /**
+   * Get language distribution (in bytes)
+   * Returns languages used in the repository with byte counts
+   */
+  async getLanguageStats(owner: string, repo: string): Promise<LanguageStats> {
+    const cacheKey = `repo:languages:${owner}/${repo}`
+    const CACHE_TTL = 3600 // 1 hour
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as LanguageStats
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    const { data } = await this.octokit.repos.listLanguages({
+      owner,
+      repo,
+    })
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(data), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache language stats:', error)
+    }
+
+    return data
+  }
+
+  /**
+   * Get code frequency statistics (weekly additions/deletions)
+   * ⚠️ Only available for repositories with < 10,000 commits
+   * ⚠️ First request returns 202, need to retry
+   */
+  async getCodeFrequency(owner: string, repo: string): Promise<CodeFrequency[]> {
+    const cacheKey = `repo:code-frequency:${owner}/${repo}`
+    const CACHE_TTL = 3600 // 1 hour
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as CodeFrequency[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    const response = await this.fetchCodeFrequencyWithRetry(owner, repo)
+
+    const stats: CodeFrequency[] = response.data.map((item) => ({
+      week: item[0] ?? 0,
+      additions: item[1] ?? 0,
+      deletions: Math.abs(item[2] ?? 0),
+    }))
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(stats), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache code frequency stats:', error)
+    }
+
+    return stats
+  }
+
+  /**
+   * Fetch code frequency with retry logic (recursive)
+   */
+  private async fetchCodeFrequencyWithRetry(
+    owner: string,
+    repo: string,
+    attempt = 1
+  ): Promise<{ data: number[][] }> {
+    const maxAttempts = 3
+    const response = await this.octokit.repos.getCodeFrequencyStats({ owner, repo })
+
+    if (response.status === 200 && response.data.length > 0) {
+      return { data: response.data }
+    }
+
+    if (response.status === 202 && attempt < maxAttempts) {
+      await new Promise((resolve) => setTimeout(resolve, 2000))
+      return this.fetchCodeFrequencyWithRetry(owner, repo, attempt + 1)
+    }
+
+    throw new Error(`Failed to fetch code frequency after ${String(attempt)} attempts`)
+  }
+
+  /**
+   * Get repository file tree structure
+   * @param recursive If true, get all files recursively
+   */
+  async getFileTree(
+    owner: string,
+    repo: string,
+    branch = 'main',
+    recursive = true
+  ): Promise<FileTree[]> {
+    const cacheKey = `repo:tree:${owner}/${repo}:${branch}:${String(recursive)}`
+    const CACHE_TTL = 1800 // 30 minutes
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as FileTree[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    // First, get the branch to find the tree SHA
+    const { data: branchData } = await this.octokit.repos.getBranch({
+      owner,
+      repo,
+      branch,
+    })
+
+    const treeSha = branchData.commit.commit.tree.sha
+
+    // Then get the tree
+    const { data } = await this.octokit.git.getTree({
+      owner,
+      repo,
+      tree_sha: treeSha,
+      recursive: recursive ? 'true' : undefined,
+    })
+
+    const fileTree: FileTree[] = data.tree.map((item) => ({
+      path: item.path,
+      mode: item.mode,
+      type: item.type as 'blob' | 'tree',
+      sha: item.sha,
+      size: item.size,
+      url: item.url,
+    }))
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(fileTree), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache file tree:', error)
+    }
+
+    return fileTree
+  }
+
+  /**
+   * Analyze hot files (most frequently modified files)
+   * This analyzes recent commits to find which files are changed most often
+   * @param limit Number of commits to analyze (default: 100)
+   * @param topN Return top N hot files (default: 20)
+   */
+  async getHotFiles(owner: string, repo: string, limit = 100, topN = 20): Promise<HotFile[]> {
+    const cacheKey = `repo:hot-files:${owner}/${repo}:${String(limit)}:${String(topN)}`
+    const CACHE_TTL = 1800 // 30 minutes
+
+    try {
+      const cached = await redis.get(cacheKey)
+      if (cached) {
+        return JSON.parse(cached as string) as HotFile[]
+      }
+    } catch (error) {
+      console.warn('Redis cache unavailable:', error)
+    }
+
+    // Get recent commits
+    const { data: commits } = await this.octokit.repos.listCommits({
+      owner,
+      repo,
+      per_page: Math.min(limit, 100),
+    })
+
+    // Track file changes
+    const fileChanges = new Map<
+      string,
+      {
+        count: number
+        lastModified: string
+        authors: Set<string>
+      }
+    >()
+
+    // Process commits
+    await this.processCommitsForHotFiles(owner, repo, commits, fileChanges)
+
+    // Convert to array and sort
+    const hotFiles = this.sortAndLimitHotFiles(fileChanges, topN)
+
+    try {
+      await redis.set(cacheKey, JSON.stringify(hotFiles), { ex: CACHE_TTL })
+    } catch (error) {
+      console.warn('Failed to cache hot files:', error)
+    }
+
+    return hotFiles
+  }
+
+  /**
+   * Process commits to track file changes
+   */
+  private async processCommitsForHotFiles(
+    owner: string,
+    repo: string,
+    commits: { sha: string }[],
+    fileChanges: Map<string, { count: number; lastModified: string; authors: Set<string> }>
+  ) {
+    const commitPromises = commits.map(async (commit) =>
+      this.octokit.repos
+        .getCommit({
+          owner,
+          repo,
+          ref: commit.sha,
+        })
+        .then((result) => result.data)
+        .catch((error: unknown) => {
+          console.warn(`Failed to fetch commit ${commit.sha}:`, error)
+          return null
+        })
+    )
+
+    const commitDetails = await Promise.all(commitPromises)
+
+    for (const commitDetail of commitDetails) {
+      if (!commitDetail) continue
+
+      const author = commitDetail.commit.author?.name ?? 'Unknown'
+      const date = commitDetail.commit.author?.date ?? new Date().toISOString()
+
+      if (commitDetail.files) {
+        this.updateFileChanges(commitDetail.files, fileChanges, author, date)
+      }
+    }
+  }
+
+  /**
+   * Update file changes tracking
+   */
+  private updateFileChanges(
+    files: { filename: string }[],
+    fileChanges: Map<string, { count: number; lastModified: string; authors: Set<string> }>,
+    author: string,
+    date: string
+  ) {
+    for (const file of files) {
+      const path = file.filename
+
+      if (!fileChanges.has(path)) {
+        fileChanges.set(path, {
+          count: 0,
+          lastModified: date,
+          authors: new Set(),
+        })
+      }
+
+      const fileData = fileChanges.get(path)
+      if (fileData) {
+        fileData.count++
+        fileData.authors.add(author)
+
+        // Update last modified if this commit is more recent
+        if (new Date(date) > new Date(fileData.lastModified)) {
+          fileData.lastModified = date
+        }
+      }
+    }
+  }
+
+  /**
+   * Sort and limit hot files
+   */
+  private sortAndLimitHotFiles(
+    fileChanges: Map<string, { count: number; lastModified: string; authors: Set<string> }>,
+    topN: number
+  ): HotFile[] {
+    return Array.from(fileChanges.entries())
+      .map(([path, data]) => ({
+        path,
+        changeCount: data.count,
+        lastModified: data.lastModified,
+        authors: Array.from(data.authors),
+      }))
+      .sort((a, b) => b.changeCount - a.changeCount)
+      .slice(0, topN)
+  }
+
+  /**
+   * Get file structure summary (counts by type)
+   */
+  async getFileStructureSummary(owner: string, repo: string, branch = 'main') {
+    const files = await this.getFileTree(owner, repo, branch, true)
+
+    const summary = {
+      totalFiles: 0,
+      totalDirectories: 0,
+      totalSize: 0,
+      filesByExtension: new Map<string, number>(),
+      largestFiles: [] as { path: string; size: number }[],
+    }
+
+    for (const file of files) {
+      if (file.type === 'blob') {
+        summary.totalFiles++
+        summary.totalSize += file.size ?? 0
+
+        // Track by extension
+        const ext = file.path.split('.').pop() ?? 'no-extension'
+        const currentCount = summary.filesByExtension.get(ext) ?? 0
+        summary.filesByExtension.set(ext, currentCount + 1)
+      } else {
+        summary.totalDirectories++
+      }
+    }
+
+    // Get top 10 largest files
+    const largestFiles = files
+      .filter((f) => f.type === 'blob' && f.size)
+      .sort((a, b) => (b.size ?? 0) - (a.size ?? 0))
+      .slice(0, 10)
+      .map((f) => ({ path: f.path, size: f.size ?? 0 }))
+
+    return {
+      ...summary,
+      filesByExtension: Object.fromEntries(summary.filesByExtension),
+      largestFiles,
+    }
+  }
+}