diff --git a/frontend/src/types.ts b/frontend/src/types.ts
new file mode 100644
index 0000000..8c2350d
--- /dev/null
+++ b/frontend/src/types.ts
@@ -0,0 +1,124 @@
+// src/types.ts
+
+export type QuestionType =
+  | 'multiple-choice'
+  | 'multiple-select'
+  | 'short-answer'
+  | 'translation'
+  | 'math-input'
+  | 'essay'
+  | 'match'
+  | 'order'
+
+export interface Choice {
+  id: string
+  text: string
+}
+
+export interface MatchItem {
+  id: string
+  text: string
+}
+
+export interface QuestionImage {
+  src: string
+  alt?: string
+  caption?: string
+}
+
+export interface QuestionAudio {
+  src: string
+}
+
+export interface QuestionCode {
+  language: string
+  content: string
+}
+
+export interface QuestionTable {
+  headers: string[]
+  rows: string[][]
+}
+
+export interface Question {
+  id: string
+  type: QuestionType
+  category?: string
+  points?: number
+  prompt: string
+  explanation?: string
+  image?: QuestionImage
+  audio?: QuestionAudio
+  code?: QuestionCode
+  table?: QuestionTable
+  svg?: string
+  answer?: string | string[] | Record<string, string>
+  acceptedForms?: string[]
+  caseSensitive?: boolean
+  ignorePunctuation?: boolean
+  ignoreAccents?: boolean
+  sourceLanguage?: string
+  targetLanguage?: string
+  choices?: Choice[]
+  minWords?: number
+  rubric?: string[]
+  left?: MatchItem[]
+  right?: MatchItem[]
+  items?: MatchItem[]
+}
+
+export interface Exam {
+  title: string
+  subtitle?: string
+  author?: string
+  timeLimitMinutes?: number | null
+  feedbackMode?: 'end' | 'immediate'
+  passingScore?: number
+  categories?: string[]
+  questions: Question[]
+}
+
+export type FeedbackMode = 'immediate' | 'end'
+
+export interface ExamState {
+  currentIdx: number
+  answers: Record<string, unknown>
+  flags: Record<string, boolean>
+  revealed: Record<string, boolean>
+  startedAt: number
+  completedAt?: number
+  feedbackMode: FeedbackMode
+}
+
+export interface HistoryEntry {
+  id: string
+  title: string
+  completedAt: number
+  elapsedMs: number
+  gradedCount: number
+  correctCount: number
+  totalPoints: number
+  scorePoints: number
+  passingScore: number
+  exam: Exam
+  state: ExamState
+}
+
+export type GradeStatus = 'correct' | 'wrong' | 'ungraded' | 'unanswered'
+
+export interface GradeResult {
+  status: GradeStatus
+  correct: boolean
+  points: number
+}
+
+export type AppScreen = 'landing' | 'exam' | 'results' | 'review'
+export type ThemeMode = 'light' | 'dark'
+export type FontSize = 'small' | 'medium' | 'large'
+export type FeedbackTweak = 'auto' | 'immediate' | 'end'
+
+export interface Tweaks {
+  theme: ThemeMode
+  fontSize: FontSize
+  feedbackMode: FeedbackTweak
+}