diff --git a/packages/core/src/e2e-helpers.ts b/packages/core/src/e2e-helpers.ts
new file mode 100644
index 0000000000..4f4ce06a5d
--- /dev/null
+++ b/packages/core/src/e2e-helpers.ts
@@ -0,0 +1,256 @@
+import type { SegmentEvent } from './segment-event'
+import type {
+  E2EAudienceEventBase,
+  E2EEngageAudienceEventOptions,
+  E2EEngageAudienceEvent,
+  E2EJourneysV1AudienceEventOptions,
+  E2EJourneysV1AudienceTrackEvent,
+  E2EJourneysV2AudienceEventOptions,
+  E2EJourneysV2AudienceTrackEvent,
+  E2ERetlAudienceEventOptions,
+  E2ERetlAudienceTrackEvent
+} from './e2e-types'
+
+type E2EEventOverrides = Partial<Omit<SegmentEvent, 'type' | 'event' | 'name' | 'messageId' | 'timestamp'>>
+
+/*
+ * Regular Segment Connections event.
+ *
+ * Overloads enforce the name rules at the type level:
+ * - track: name required (becomes the event name)
+ * - page/screen: name optional
+ * - identify/group/alias: no name accepted
+ */
+export function createE2EEvent(type: 'track', name: string, overrides?: E2EEventOverrides): SegmentEvent
+export function createE2EEvent(type: 'page' | 'screen', name?: string, overrides?: E2EEventOverrides): SegmentEvent
+export function createE2EEvent(
+  type: 'identify' | 'group' | 'alias',
+  name?: undefined,
+  overrides?: E2EEventOverrides
+): SegmentEvent
+export function createE2EEvent(type: SegmentEvent['type'], name?: string, overrides?: E2EEventOverrides): SegmentEvent {
+  if (type === 'track') {
+    return {
+      type,
+      event: name,
+      messageId: '$guid',
+      timestamp: '$now',
+      ...overrides
+    }
+  }
+
+  if (type === 'page' || type === 'screen') {
+    return {
+      type,
+      name,
+      messageId: '$guid',
+      timestamp: '$now',
+      ...overrides
+    }
+  }
+
+  if (name) {
+    throw new Error(
+      `createE2EEvent: "name" is not supported for "${type}" events. Only track, page, and screen accept a name.`
+    )
+  }
+
+  return {
+    type,
+    messageId: '$guid',
+    timestamp: '$now',
+    ...overrides
+  }
+}
+
+function buildAudienceEventBase(options: E2EAudienceEventBase) {
+  const {
+    computationKey,
+    computationId,
+    externalAudienceId,
+    userId,
+    anonymousId,
+    email,
+    audienceFields,
+    includeContextTraits = true
+  } = options
+  return {
+    messageId: '$guid',
+    timestamp: '$now',
+    ...(userId && { userId }),
+    ...(anonymousId && { anonymousId }),
+    context: {
+      personas: {
+        computation_class: 'audience',
+        computation_key: computationKey,
+        computation_id: computationId,
+        ...(externalAudienceId && { external_audience_id: externalAudienceId })
+      },
+      ...(audienceFields && { audienceFields }),
+      ...(includeContextTraits && email && { traits: { email } })
+    }
+  }
+}
+
+/*
+ * Engage Audience event
+ * Supports identify and track events
+ */
+export function createE2EEngageAudienceEvent<ComputationKey extends string>(
+  options: E2EEngageAudienceEventOptions<ComputationKey>
+): E2EEngageAudienceEvent<ComputationKey> {
+  const { action, computationKey, email, enrichedTraits } = options
+  const membership = action === 'add'
+  const base = buildAudienceEventBase({ ...options, includeContextTraits: options.type === 'track' })
+
+  if (options.type === 'track') {
+    return {
+      ...base,
+      type: 'track',
+      event: options.eventName ?? 'Test Engage Audience Membership Event',
+      properties: {
+        [computationKey]: membership,
+        ...enrichedTraits
+      }
+    } as E2EEngageAudienceEvent<ComputationKey>
+  }
+
+  return {
+    ...base,
+    type: 'identify',
+    traits: {
+      [computationKey]: membership,
+      ...enrichedTraits,
+      ...(email && { email })
+    }
+  } as E2EEngageAudienceEvent<ComputationKey>
+}
+
+/*
+ * Journeys V1 events (preset journeys_step_entered_track) do not have properties[<computation_key>] value.
+ * All Journeys V1 events enter the user to the audience, never remove them.
+ * Only track events supported
+ */
+export function createE2EJourneysV1AudienceEvent<ComputationKey extends string>(
+  options: E2EJourneysV1AudienceEventOptions<ComputationKey>
+): E2EJourneysV1AudienceTrackEvent<ComputationKey> {
+  const {
+    computationKey,
+    computationId,
+    externalAudienceId,
+    userId,
+    anonymousId,
+    email,
+    audienceFields,
+    enrichedTraits
+  } = options
+
+  const event = {
+    messageId: '$guid',
+    timestamp: '$now',
+    ...(userId && { userId }),
+    ...(anonymousId && { anonymousId }),
+    type: 'track',
+    event: 'Audience Entered',
+    properties: {
+      ...enrichedTraits
+    },
+    context: {
+      personas: {
+        computation_class: 'journey_step',
+        computation_key: computationKey,
+        computation_id: computationId,
+        ...(externalAudienceId && { external_audience_id: externalAudienceId })
+      },
+      ...(audienceFields && { audienceFields }),
+      ...(email && { traits: { email } })
+    }
+  }
+
+  return event as E2EJourneysV1AudienceTrackEvent<ComputationKey>
+}
+
+/*
+ * Journeys V2 events use computation_class 'journey_step' (not 'audience') and carry
+ * journey_context / journey_metadata in properties alongside properties[<computation_key>],
+ * the membership boolean (true = entering the step / add, false = exiting / remove).
+ * Only track events supported.
+ */
+export function createE2EJourneysV2AudienceEvent<ComputationKey extends string>(
+  options: E2EJourneysV2AudienceEventOptions<ComputationKey>
+): E2EJourneysV2AudienceTrackEvent<ComputationKey> {
+  const {
+    action = 'add',
+    computationKey,
+    computationId,
+    externalAudienceId,
+    eventName,
+    journeyId,
+    journeyName,
+    userId,
+    anonymousId,
+    email,
+    audienceFields,
+    enrichedTraits
+  } = options
+
+  const membership = action === 'add'
+
+  const event = {
+    messageId: '$guid',
+    timestamp: '$now',
+    ...(userId && { userId }),
+    ...(anonymousId && { anonymousId }),
+    type: 'track',
+    event: eventName ?? 'Test Journeys V2 Audience Membership Event',
+    properties: {
+      [computationKey]: membership,
+      journey_context: {
+        [computationKey]: {}
+      },
+      journey_metadata: {
+        epoch_id: '$guid',
+        journey_id: journeyId ?? 'jver_e2e_journey',
+        journey_name: journeyName ?? 'e2e journey'
+      },
+      ...enrichedTraits
+    },
+    context: {
+      personas: {
+        computation_class: 'journey_step',
+        computation_key: computationKey,
+        computation_id: computationId,
+        ...(externalAudienceId && { external_audience_id: externalAudienceId })
+      },
+      ...(audienceFields && { audienceFields }),
+      ...(email && { traits: { email } })
+    }
+  }
+
+  return event as E2EJourneysV2AudienceTrackEvent<ComputationKey>
+}
+
+/*
+ * Reverse ETL Audience event
+ * Same payload structure as Engage track events but uses RETL-specific event names: 'new', 'updated', 'deleted'
+ * Only track events supported
+ */
+export function createE2ERetlAudienceEvent<ComputationKey extends string>(
+  options: E2ERetlAudienceEventOptions<ComputationKey>
+): E2ERetlAudienceTrackEvent<ComputationKey> {
+  const { eventName, computationKey, enrichedTraits } = options
+  const membership = eventName !== 'deleted'
+  const base = buildAudienceEventBase(options)
+
+  const event = {
+    ...base,
+    type: 'track',
+    event: eventName,
+    properties: {
+      [computationKey]: membership,
+      ...enrichedTraits
+    }
+  }
+
+  return event as E2ERetlAudienceTrackEvent<ComputationKey>
+}
diff --git a/packages/core/src/e2e-types.ts b/packages/core/src/e2e-types.ts
new file mode 100644
index 0000000000..660f347fc8
--- /dev/null
+++ b/packages/core/src/e2e-types.ts
@@ -0,0 +1,377 @@
+import type { SegmentEvent } from './segment-event'
+import type { JSONObject, JSONValue } from './json-object'
+
+export type E2EExpectation = E2ESuccessExpectation | E2EFailureExpectation | E2EErrorExpectation
+
+/**
+ * The HTTP request was sent and the destination API returned a 2xx response.
+ */
+export interface E2ESuccessExpectation {
+  status: 'success'
+  httpStatus?: E2EHttpSuccessCode
+  bodyContains?: string
+  /** Partial deep match against the JSON response body. Arrays must match length and each item is partial-matched. */
+  jsonContains?: unknown
+}
+
+/**
+ * The HTTP request was sent and the destination API returned a non-2xx response.
+ * Use this to verify that the destination rejects specific inputs (e.g., bad auth, invalid payload).
+ */
+export interface E2EFailureExpectation {
+  status: 'failure'
+  httpStatus: E2EHttpFailureCode
+  bodyContains?: string
+  /** Partial deep match against the JSON response body. Arrays must match length and each item is partial-matched. */
+  jsonContains?: unknown
+}
+
+/**
+ * Our action code threw before making an HTTP request.
+ * The request never left. Use this to verify client-side validation
+ * (e.g., PayloadValidationError when required fields are missing).
+ */
+export interface E2EErrorExpectation {
+  status: 'error'
+  errorType: string
+  errorMessage?: string
+}
+
+/**
+ * Dynamic value markers that the runner resolves at execution time.
+ *
+ * - '$now'                  → current ISO 8601 timestamp (e.g., '2026-05-28T14:32:01.000Z')
+ * - '$guid'                 → fresh UUID v4, unique each occurrence
+ * - '$guid:<name>'          → UUID v4, consistent within a single fixture execution.
+ *                             All occurrences of the same name resolve to the same value.
+ * - '$externalAudienceId'   → resolved after createAudience step returns the destination's audience ID
+ */
+export type E2EDynamicValue = '$now' | '$guid' | `$guid:${string}` | '$externalAudienceId'
+
+export type E2EExecutionMode = 'single' | 'batch' | 'batchWithMultistatus'
+
+export type E2EFixture = E2ESingleFixture | E2EBatchFixture | E2EBatchWithMultistatusFixture
+
+export interface E2EBaseFixture {
+  /** Human-readable name for the test case, shown in runner output. */
+  description: string
+  /** FQL query that determines whether the event matches this subscription. */
+  subscribe: string
+  /** Mapping kit directives that transform the event into the action's payload shape. */
+  mapping: JSONObject
+  /** The expected outcome of executing this fixture. */
+  expect: E2EExpectation
+  /** Hint shown in verbose mode when this fixture fails. Helps developers diagnose common issues. */
+  verboseFailureHint?: string
+  /** Feature flags passed to the action, to exercise flag-gated code branches end-to-end. */
+  features?: Record<string, boolean>
+  /**
+   * Max times the runner re-runs this fixture if it fails, with exponential backoff between attempts.
+   * Overrides the run-level retry default. Useful for destinations with eventual consistency
+   * (e.g. writes to a freshly-created audience that briefly return a transient error).
+   */
+  retries?: number
+}
+
+export interface E2ESingleFixture extends E2EBaseFixture {
+  /** Executes via onEvent() with a single event. */
+  mode: 'single'
+  /**
+   * The Segment event (track, identify, page, screen, etc.) sent into the action.
+   * String values may use dynamic markers ($now, $guid, $guid:<name>) that the
+   * runner resolves before execution.
+   */
+  event: SegmentEvent
+}
+
+export interface E2EBatchFixture extends E2EBaseFixture {
+  /** Executes via onBatch() with multiple events. Response is a standard HTTP response. */
+  mode: 'batch'
+  /**
+   * Array of Segment events sent into the action as a batch.
+   * String values may use dynamic markers ($now, $guid, $guid:<name>) that the
+   * runner resolves before execution.
+   */
+  events: SegmentEvent[]
+}
+
+export interface E2EBatchWithMultistatusFixture extends E2EBaseFixture {
+  /** Executes via onBatch(). Response is a per-item MultiStatusResponse array. */
+  mode: 'batchWithMultistatus'
+  /**
+   * Array of Segment events sent into the action as a batch.
+   * String values may use dynamic markers ($now, $guid, $guid:<name>) that the
+   * runner resolves before execution.
+   */
+  events: SegmentEvent[]
+}
+
+export interface E2EAudienceEventBase {
+  computationKey: string
+  computationId: string
+  externalAudienceId?: string
+  userId?: string
+  anonymousId?: string
+  email?: string
+  audienceFields?: Record<string, JSONValue>
+  includeContextTraits?: boolean
+}
+
+interface E2EEngageAudienceEventOptionsBase<ComputationKey extends string = string> {
+  action: 'add' | 'remove'
+  computationKey: ComputationKey
+  computationId: string
+  externalAudienceId?: string
+  userId?: string
+  anonymousId?: string
+  email?: string
+  audienceFields?: Record<string, JSONValue>
+  enrichedTraits?: Record<string, JSONValue>
+}
+
+export interface E2EEngageAudienceTrackEventOptions<ComputationKey extends string = string>
+  extends E2EEngageAudienceEventOptionsBase<ComputationKey> {
+  type: 'track'
+  eventName?: string
+}
+
+export interface E2EEngageAudienceIdentifyEventOptions<ComputationKey extends string = string>
+  extends E2EEngageAudienceEventOptionsBase<ComputationKey> {
+  type: 'identify'
+  /** identify events do not carry an event name. */
+  eventName?: never
+}
+
+export type E2EEngageAudienceEventOptions<ComputationKey extends string = string> =
+  | E2EEngageAudienceTrackEventOptions<ComputationKey>
+  | E2EEngageAudienceIdentifyEventOptions<ComputationKey>
+
+export interface E2EJourneysV1AudienceEventOptions<ComputationKey extends string = string> {
+  computationKey: ComputationKey
+  computationId: string
+  externalAudienceId?: string
+  userId?: string
+  anonymousId?: string
+  email?: string
+  audienceFields?: Record<string, JSONValue>
+  enrichedTraits?: Record<string, JSONValue>
+}
+
+export interface E2EJourneysV2AudienceEventOptions<ComputationKey extends string = string> {
+  /** Whether the user is entering ('add') or exiting ('remove') the journey step. Sets properties[computationKey]. Defaults to 'add'. */
+  action?: 'add' | 'remove'
+  computationKey: ComputationKey
+  computationId: string
+  externalAudienceId?: string
+  eventName?: string
+  journeyId?: string
+  journeyName?: string
+  userId?: string
+  anonymousId?: string
+  email?: string
+  audienceFields?: Record<string, JSONValue>
+  enrichedTraits?: Record<string, JSONValue>
+}
+
+export interface E2ERetlAudienceEventOptions<ComputationKey extends string = string> {
+  eventName: 'new' | 'updated' | 'deleted'
+  computationKey: ComputationKey
+  computationId: string
+  externalAudienceId?: string
+  userId?: string
+  anonymousId?: string
+  email?: string
+  audienceFields?: Record<string, JSONValue>
+  enrichedTraits?: Record<string, JSONValue>
+}
+
+export interface E2ERetlAudienceTrackEvent<ComputationKey extends string = string> extends SegmentEvent {
+  type: 'track'
+  event: 'new' | 'updated' | 'deleted'
+  messageId: string
+  timestamp: string
+  context: {
+    personas: {
+      computation_class: 'audience'
+      computation_key: ComputationKey
+      computation_id: string
+      external_audience_id?: string
+    }
+    traits?: { email?: string }
+    audienceFields?: Record<string, JSONValue>
+  }
+  properties: { [key in ComputationKey]: boolean } & { [k: string]: JSONValue }
+}
+
+export interface E2EJourneysV1AudienceTrackEvent<ComputationKey extends string = string> extends SegmentEvent {
+  type: 'track'
+  event: 'Audience Entered'
+  messageId: string
+  timestamp: string
+  context: {
+    personas: {
+      computation_class: 'journey_step'
+      computation_key: ComputationKey
+      computation_id: string
+      external_audience_id?: string
+    }
+    traits?: { email?: string }
+    audienceFields?: Record<string, JSONValue>
+  }
+  properties: { [k: string]: JSONValue }
+}
+
+export interface E2EJourneysV2AudienceTrackEvent<ComputationKey extends string = string> extends SegmentEvent {
+  type: 'track'
+  event: string
+  messageId: string
+  timestamp: string
+  context: {
+    personas: {
+      computation_class: 'journey_step'
+      computation_key: ComputationKey
+      computation_id: string
+      external_audience_id?: string
+    }
+    traits?: { email?: string }
+    audienceFields?: Record<string, JSONValue>
+  }
+  properties: {
+    journey_context: { [k: string]: JSONValue }
+    journey_metadata: { journey_id: string; journey_name: string; [k: string]: JSONValue }
+  } & { [key in ComputationKey]: boolean } & { [k: string]: JSONValue }
+}
+
+export interface E2EEngageAudienceTrackEvent<ComputationKey extends string = string> extends SegmentEvent {
+  type: 'track'
+  event: string
+  messageId: string
+  timestamp: string
+  context: {
+    personas: {
+      computation_class: 'audience'
+      computation_key: ComputationKey
+      computation_id: string
+      external_audience_id?: string
+    }
+    traits?: { email?: string }
+    audienceFields?: Record<string, JSONValue>
+  }
+  properties: { [key in ComputationKey]: boolean } & { [k: string]: JSONValue }
+}
+
+export interface E2EEngageAudienceIdentifyEvent<ComputationKey extends string = string> extends SegmentEvent {
+  type: 'identify'
+  messageId: string
+  timestamp: string
+  context: {
+    personas: {
+      computation_class: 'audience'
+      computation_key: ComputationKey
+      computation_id: string
+      external_audience_id?: string
+    }
+    audienceFields?: Record<string, JSONValue>
+  }
+  traits: { [key in ComputationKey]: boolean } & { [k: string]: JSONValue }
+}
+
+export type E2EEngageAudienceEvent<ComputationKey extends string = string> =
+  | E2EEngageAudienceTrackEvent<ComputationKey>
+  | E2EEngageAudienceIdentifyEvent<ComputationKey>
+
+export interface E2ESettingsSecretValue {
+  $env: string
+}
+
+export interface E2ESettingsObject {
+  [key: string]: string | number | boolean | E2ESettingsSecretValue | E2ESettingsObject
+}
+
+export interface E2EDestinationConfig {
+  settings: E2ESettingsObject
+}
+
+export interface E2ETeardownContext {
+  settings: Record<string, unknown>
+}
+
+export interface E2ETeardownAudienceContext extends E2ETeardownContext {
+  externalAudienceId: string
+  audienceSettings: Record<string, unknown>
+}
+
+export interface E2EAudienceConfig {
+  /** Name of the audience to create/test against. Used as the audienceName param for createAudience. */
+  audienceName: string
+  /** Audience-level settings passed to createAudience and getAudience (e.g., id_type, owner_email). */
+  audienceSettings: Record<string, unknown>
+  /** When true, the runner calls createAudience before executing fixtures and captures the externalAudienceId. */
+  createAudience: boolean
+  /** When true, the runner calls getAudience after fixtures to verify the audience still exists. */
+  getAudience: boolean
+  /** When a function, the runner calls it after all tests to clean up the audience. Set to false to skip. */
+  teardown: false | ((context: E2ETeardownAudienceContext) => Promise<void>)
+}
+
+export interface E2EAudienceDestinationConfig extends E2EDestinationConfig {
+  audience: E2EAudienceConfig
+}
+
+export type E2EHttpSuccessCode = 200 | 201 | 202 | 203 | 204 | 205 | 206 | 207 | 208 | 226
+
+export type E2EHttpFailureCode =
+  | 300
+  | 301
+  | 302
+  | 303
+  | 304
+  | 305
+  | 306
+  | 307
+  | 308
+  | 400
+  | 401
+  | 402
+  | 403
+  | 404
+  | 405
+  | 406
+  | 407
+  | 408
+  | 409
+  | 410
+  | 411
+  | 412
+  | 413
+  | 414
+  | 415
+  | 416
+  | 417
+  | 418
+  | 421
+  | 422
+  | 423
+  | 424
+  | 425
+  | 426
+  | 428
+  | 429
+  | 431
+  | 451
+  | 499
+  | 500
+  | 501
+  | 502
+  | 503
+  | 504
+  | 505
+  | 506
+  | 507
+  | 508
+  | 509
+  | 510
+  | 511
+  | 529
+  | 598
+  | 599
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 26a3884eab..2694896e2a 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -112,3 +112,42 @@ export {
 export { validateSchema } from './schema-validation'
 export { resolveAudienceMembership } from './audience-membership'
 export { FLAGS } from './flags'
+
+export {
+  createE2EEvent,
+  createE2EEngageAudienceEvent,
+  createE2EJourneysV1AudienceEvent,
+  createE2EJourneysV2AudienceEvent,
+  createE2ERetlAudienceEvent
+} from './e2e-helpers'
+export type {
+  E2EFixture,
+  E2EBaseFixture,
+  E2ESingleFixture,
+  E2EBatchFixture,
+  E2EBatchWithMultistatusFixture,
+  E2EExecutionMode,
+  E2EExpectation,
+  E2ESuccessExpectation,
+  E2EFailureExpectation,
+  E2EErrorExpectation,
+  E2EDestinationConfig,
+  E2EAudienceDestinationConfig,
+  E2EAudienceConfig,
+  E2ETeardownContext,
+  E2ETeardownAudienceContext,
+  E2ESettingsSecretValue,
+  E2EDynamicValue,
+  E2EEngageAudienceEventOptions,
+  E2EEngageAudienceEvent,
+  E2EEngageAudienceTrackEvent,
+  E2EEngageAudienceIdentifyEvent,
+  E2EJourneysV1AudienceEventOptions,
+  E2EJourneysV1AudienceTrackEvent,
+  E2EJourneysV2AudienceEventOptions,
+  E2EJourneysV2AudienceTrackEvent,
+  E2ERetlAudienceEventOptions,
+  E2ERetlAudienceTrackEvent,
+  E2EHttpSuccessCode,
+  E2EHttpFailureCode
+} from './e2e-types'