diff --git a/src/backend/mocks/default_handlers.js b/src/backend/mocks/default_handlers.js
index 64a18d4e..299d1de4 100644
--- a/src/backend/mocks/default_handlers.js
+++ b/src/backend/mocks/default_handlers.js
@@ -1,9 +1 @@
-// import { http, HttpResponse } from 'msw'
-
-// implementations for msw v2 handlers go in this file
-// see old.default_handlers.js for reference
-// this note can get removed after migration
-
-export const handlers = [
-
-]
+export { handlers } from './handlers'
diff --git a/src/backend/mocks/handlers/auth.js b/src/backend/mocks/handlers/auth.js
new file mode 100644
index 00000000..328eff00
--- /dev/null
+++ b/src/backend/mocks/handlers/auth.js
@@ -0,0 +1,47 @@
+import { rest } from 'msw'
+import { makeUser } from './shared'
+import { mockState } from './state'
+
+export const authHandlers = [
+  rest.post(/\/api\/auth\/login$/, (req, res, ctx) => {
+    mockState.user = makeUser(req.body.email)
+    return res(ctx.json({
+      user: mockState.user,
+    }), ctx.cookie('authToken', 'token_value'))
+  }),
+  rest.get(/\/api\/auth\/login$/, (req, res, ctx) => {
+    const { authToken } = req.cookies
+    if (authToken !== 'token_value') {
+      return res(ctx.status(401))
+    }
+    return res(ctx.json({
+      user: mockState.user,
+    }))
+  }),
+  rest.delete(/\/api\/auth\/login$/, (_, res, ctx) => {
+    mockState.user = makeUser()
+    return res(ctx.status(204))
+  }),
+  rest.post(/\/api\/user\/forgotPassword$/, (req, res, ctx) => {
+    if (req.body.email === 'serverError@example.com') {
+      return res(ctx.status(400, 'Mocked Server Error'))
+    }
+    return res(ctx.status(200))
+  }),
+  rest.post(/\/api\/user\/resetPassword$/, (_, res, ctx) => res(ctx.status(200))),
+  rest.post(/\/api\/user\/sendVerifyEmail$/, (_, res, ctx) => res(ctx.json({ message: 'Already verified' }))),
+  rest.post(/\/api\/user\/verifyEmail$/, (_, res, ctx) => res(ctx.status(200))),
+  rest.post(/\/api\/complaint\/sendMessage$/, (_, res, ctx) => res(ctx.status(200))),
+  rest.post(/\/api\/contact\/sendMessage$/, (req, res, ctx) => {
+    if (req.body.name === 'recaptchaError') {
+      return res(ctx.status(401, 'Mocked recaptcha Error'))
+    }
+    if (req.body.name === '') {
+      return res(ctx.status(400, 'Mocked empty name Error'))
+    }
+    if (req.body.recaptcha === '') {
+      return res(ctx.status(400, 'Mocked recaptcha empty Error'))
+    }
+    return res(ctx.status(200))
+  }),
+]
diff --git a/src/backend/mocks/handlers/index.js b/src/backend/mocks/handlers/index.js
new file mode 100644
index 00000000..3ced186f
--- /dev/null
+++ b/src/backend/mocks/handlers/index.js
@@ -0,0 +1,6 @@
+export const handlers = typeof Response === 'undefined'
+  ? []
+  : [
+    ...require('./auth').authHandlers,
+    ...require('./wiki').wikiHandlers,
+  ]
diff --git a/src/backend/mocks/handlers/shared.js b/src/backend/mocks/handlers/shared.js
new file mode 100644
index 00000000..95056dc2
--- /dev/null
+++ b/src/backend/mocks/handlers/shared.js
@@ -0,0 +1,98 @@
+export function makeUser (email = 'test@local') {
+  return {
+    id: 1,
+    email,
+    verified: true,
+    created_at: '2020-01-01',
+    updated_at: '2020-01-01',
+  }
+}
+
+export function getStoredWikis () {
+  try {
+    return JSON.parse(localStorage.getItem('msw-myWikis')) || []
+  } catch (error) {
+    return []
+  }
+}
+
+export function persistWikis (wikis) {
+  localStorage.setItem('msw-myWikis', JSON.stringify(wikis))
+}
+
+export function wikiDiscovery (referrer, params) {
+  const pseudorandom = {
+    seed: 1,
+    next: function () {
+      const x = Math.sin(this.seed++) * 10000
+      return x - Math.floor(x)
+    },
+  }
+
+  const names = [
+    'Wikibase Name',
+    'A Very Long Wikibase Name',
+  ]
+
+  let wikis = [...Array(75).keys()].map((id) => {
+    const wiki = {
+      id,
+      domain: id + '-wikibase.wbaas.localhost',
+      sitename: id + ' - ' + names[id % names.length],
+      wiki_site_stats: null,
+      logo_url: null,
+    }
+
+    if (pseudorandom.next() >= 0.1) {
+      wiki.wiki_site_stats = {
+        pages: Math.ceil(pseudorandom.next() * 250),
+      }
+    }
+
+    if (pseudorandom.next() >= 0.5) {
+      wiki.logo_url = new URL(referrer).origin + '/favicon.ico'
+    }
+    return wiki
+  })
+
+  if (parseInt(params.get('is_active'))) {
+    wikis = wikis.filter((wiki) => {
+      const stats = wiki.wiki_site_stats
+      return stats && stats.pages > 1
+    })
+  }
+
+  if (params.get('sort') === 'sitename') {
+    wikis = wikis.sort((a, b) => {
+      let sort = a.sitename.localeCompare(b.sitename, 'en', { numeric: true })
+      if (params.get('direction') === 'desc') {
+        sort *= -1
+      }
+      return sort
+    })
+  }
+
+  if (params.get('sort') === 'pages') {
+    wikis = wikis.sort((a, b) => {
+      const aPages = a.wiki_site_stats ? a.wiki_site_stats.pages : 0
+      const bPages = b.wiki_site_stats ? b.wiki_site_stats.pages : 0
+      if (params.get('direction') === 'desc') {
+        return bPages - aPages
+      }
+      return aPages - bPages
+    })
+  }
+
+  const currentPage = parseInt(params.get('page'))
+  const resultsPerPage = parseInt(params.get('per_page'))
+  const start = (currentPage - 1) * resultsPerPage
+  const end = start + resultsPerPage
+
+  return {
+    data: wikis.slice(start, end),
+    meta: {
+      last_page: Math.ceil(wikis.length / resultsPerPage),
+      total: wikis.length,
+    },
+  }
+}
diff --git a/src/backend/mocks/handlers/state.js b/src/backend/mocks/handlers/state.js
new file mode 100644
index 00000000..8918090e
--- /dev/null
+++ b/src/backend/mocks/handlers/state.js
@@ -0,0 +1,27 @@
+import { makeUser, getStoredWikis, persistWikis } from './shared'
+
+export const mockState = {
+  user: makeUser(),
+  myWikis: getStoredWikis(),
+  entityImportCalledTimes: 0,
+}
+
+export function syncMyWikis () {
+  mockState.myWikis = getStoredWikis()
+}
+
+export function nextWikiId () {
+  const lastWikiId = mockState.myWikis.reduce((max, wiki) => {
+    const id = Number(wiki.id)
+    return Number.isFinite(id) ? Math.max(max, id) : max
+  }, 0)
+
+  return lastWikiId + 1
+}
+
+export function resetMockData () {
+  mockState.user = makeUser()
+  mockState.myWikis = []
+  mockState.entityImportCalledTimes = 0
+  persistWikis(mockState.myWikis)
+}
diff --git a/src/backend/mocks/handlers/wiki.js b/src/backend/mocks/handlers/wiki.js
new file mode 100644
index 00000000..db9a60f2
--- /dev/null
+++ b/src/backend/mocks/handlers/wiki.js
@@ -0,0 +1,87 @@
+import { rest } from 'msw'
+import { mockState, nextWikiId, syncMyWikis } from './state'
+import { persistWikis, wikiDiscovery } from './shared'
+
+const makeNewWiki = ({ domain, sitename }) => {
+  const wikiId = nextWikiId()
+  const newWiki = {
+    id: wikiId,
+    domain,
+    sitename,
+    deleted_at: null,
+    created_at: '2020-01-01',
+    updated_at: '2020-01-01',
+    pivot: {
+      user_id: mockState.user.id,
+      wiki_id: wikiId,
+    },
+    wiki_managers: [{
+      email: mockState.user.email,
+      pivot: {
+        user_id: mockState.user.id,
+        wiki_id: wikiId,
+      },
+    }],
+    wiki_db_version: {
+      id: 101,
+      wiki_id: wikiId,
+      version: 'mw1.33-wbs1',
+    },
+    public_settings: [],
+  }
+
+  mockState.myWikis.push(newWiki)
+  persistWikis(mockState.myWikis)
+
+  return newWiki
+}
+
+export const wikiHandlers = [
+  rest.post(/\/api\/wiki\/entityImport$/, (_, res, ctx) => {
+    return res(ctx.json({ data: { status: 'pending', payload: {}, started_at: new Date().toJSON() } }))
+  }),
+  rest.get(/\/api\/wiki\/entityImport$/, (_, res, ctx) => {
+    mockState.entityImportCalledTimes += 1
+    switch (mockState.entityImportCalledTimes) {
+      case 1:
+        return res(ctx.json({ data: [] }))
+      case 2:
+        return res(ctx.json({ data: [{ status: 'pending' }] }))
+      default:
+        return res(ctx.json({ data: [{ status: 'success' }] }))
+    }
+  }),
+  rest.get(/\/api\/wiki\/count$/, (_, res, ctx) => res(ctx.json({ data: 1 }))),
+  rest.post(/\/api\/wiki\/mine$/, (_, res, ctx) => {
+    syncMyWikis()
+    return res(ctx.json({ wikis: mockState.myWikis, count: mockState.myWikis.length, limit: false }))
+  }),
+  rest.post(/\/api\/wiki\/create$/, (req, res, ctx) => {
+    return res(ctx.json({ data: makeNewWiki(req.body) }))
+  }),
+  rest.post(/\/api\/wiki\/delete$/, (req, res, ctx) => {
+    const wikiId = req.body.wiki
+    const wikiIndex = mockState.myWikis.findIndex(w => w.id === Number(wikiId))
+    if (wikiIndex < 0) {
+      return res(ctx.status(404))
+    }
+
+    mockState.myWikis.splice(wikiIndex, 1)
+    persistWikis(mockState.myWikis)
+    return res(ctx.status(200))
+  }),
+  rest.post(/\/api\/wiki\/logo\/update$/, (_, res, ctx) => res(ctx.status(200))),
+  rest.post(/\/api\/wiki\/setting\/.*?\/update$/, (_, res, ctx) => res(ctx.status(200))),
+  rest.post(/\/api\/wiki\/details$/, (req, res, ctx) => {
+    syncMyWikis()
+    const wikiId = req.body.wiki
+    const wikiDetails = mockState.myWikis.find(w => w.id === Number(wikiId))
+    if (!wikiDetails) {
+      return res(ctx.status(404))
+    }
+    return res(ctx.json({ data: wikiDetails }), ctx.status(200))
+  }),
+  rest.get(/\/api\/wiki$/, (req, res, ctx) => {
+    return res(ctx.json(wikiDiscovery(req.referrer, req.url.searchParams)))
+  }),
+]
diff --git a/src/backend/mocks/index.js b/src/backend/mocks/index.js
new file mode 100644
index 00000000..259c62f1
--- /dev/null
+++ b/src/backend/mocks/index.js
@@ -0,0 +1,5 @@
+export { MOCK_SCENARIOS, getMockScenario, setMockScenario, resetMockState } from './state'
+
+export const handlers = typeof Response === 'undefined'
+  ? []
+  : require('./handlers').handlers
diff --git a/src/backend/mocks/state.js b/src/backend/mocks/state.js
new file mode 100644
index 00000000..eab5975b
--- /dev/null
+++ b/src/backend/mocks/state.js
@@ -0,0 +1,35 @@
+const STORAGE_KEY = 'msw-scenario'
+const DEFAULT_SCENARIO = 'happy-path'
+
+export const MOCK_SCENARIOS = [
+  'happy-path',
+  'empty-state',
+  'auth-error',
+  'server-error',
+]
+
+export function getMockScenario () {
+  if (typeof localStorage === 'undefined') {
+    return DEFAULT_SCENARIO
+  }
+
+  const saved = localStorage.getItem(STORAGE_KEY)
+  return MOCK_SCENARIOS.includes(saved) ? saved : DEFAULT_SCENARIO
+}
+
+export function setMockScenario (scenario) {
+  if (!MOCK_SCENARIOS.includes(scenario)) {
+    throw new Error(`Unsupported mock scenario: ${scenario}`)
+  }
+
+  localStorage.setItem(STORAGE_KEY, scenario)
+  return getMockScenario()
+}
+
+export function resetMockState () {
+  if (typeof localStorage !== 'undefined') {
+    localStorage.removeItem(STORAGE_KEY)
+    localStorage.removeItem('msw-myWikis')
+  }
+  return DEFAULT_SCENARIO
+}
diff --git a/tests/unit/mocks.spec.js b/tests/unit/mocks.spec.js
new file mode 100644
index 00000000..141c851c
--- /dev/null
+++ b/tests/unit/mocks.spec.js
@@ -0,0 +1,26 @@
+import { getMockScenario, setMockScenario, resetMockState } from '@/backend/mocks'
+import { handlers as modularHandlers } from '@/backend/mocks/handlers'
+import { handlers as publicHandlers } from '@/backend/mocks'
+
+describe('MSW mock configuration', () => {
+  beforeEach(() => {
+    localStorage.clear()
+    resetMockState()
+  })
+
+  it('defaults to the happy-path scenario', () => {
+    expect(getMockScenario()).toBe('happy-path')
+  })
+
+  it('allows switching the active scenario in local storage', () => {
+    setMockScenario('empty-state')
+
+    expect(getMockScenario()).toBe('empty-state')
+  })
+
+  it('uses the same shared handler registry for browser and tests', () => {
+    expect(Array.isArray(publicHandlers)).toBe(true)
+    expect(Array.isArray(modularHandlers)).toBe(true)
+    expect(modularHandlers).toEqual(publicHandlers)
+  })
+})