diff --git a/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.spec.ts b/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.spec.ts
new file mode 100644
index 00000000000..c5570bb2878
--- /dev/null
+++ b/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.spec.ts
@@ -0,0 +1,438 @@
+import { deepFreeze, useBoolean } from '@standardnotes/utils'
+import { PayloadSource } from '../Types/PayloadSource'
+import { TransferPayload } from '../../TransferPayload/Interfaces/TransferPayload'
+import { ItemContent, FillItemContent } from '../../Content/ItemContent'
+import { PurePayload } from './PurePayload'
+import { SyncResolvedParams, SyncResolvedPayload } from '../../../Runtime/Deltas/Utilities/SyncResolvedPayload'
+import { PersistentSignatureData } from '../../../Runtime/Encryption/PersistentSignatureData'
+import { ContentType } from '@standardnotes/domain-core'
+
+// Mock the utils functions
+jest.mock('@standardnotes/utils', () => ({
+  deepFreeze: jest.fn(),
+  useBoolean: jest.fn((value, defaultValue) => value !== undefined ? !!value : defaultValue),
+}))
+
+// Mock the content type encryption check
+jest.mock('../../../Runtime/Encryption/ContentTypeUsesRootKeyEncryption', () => ({
+  ContentTypeUsesRootKeyEncryption: jest.fn((contentType: string) => {
+    const rootKeyTypes = [
+      ContentType.TYPES.RootKey,
+      ContentType.TYPES.ItemsKey,
+      ContentType.TYPES.EncryptedStorage,
+      ContentType.TYPES.TrustedContact,
+      ContentType.TYPES.KeySystemRootKey,
+    ]
+    return rootKeyTypes.includes(contentType)
+  }),
+}))
+
+class TestPurePayload extends PurePayload<TransferPayload<ItemContent>, ItemContent> {
+  copy(override?: Partial<TransferPayload>, source?: PayloadSource): this {
+    const newPayload = {
+      ...this.ejected(),
+      ...override,
+    }
+    return new TestPurePayload(newPayload, source || this.source) as this
+  }
+
+  copyAsSyncResolved(override?: Partial<TransferPayload<ItemContent>> & SyncResolvedParams, source?: PayloadSource): SyncResolvedPayload {
+    const newPayload = {
+      ...this.ejected(),
+      ...override,
+    }
+    return new TestPurePayload(newPayload, source || this.source) as any
+  }
+}
+
+describe('PurePayload', () => {
+  const mockDeepFreeze = deepFreeze as jest.MockedFunction<typeof deepFreeze>
+  const mockUseBoolean = useBoolean as jest.MockedFunction<typeof useBoolean>
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+    mockDeepFreeze.mockImplementation((obj) => obj)
+    mockUseBoolean.mockImplementation((value, defaultValue) => value !== undefined ? !!value : defaultValue)
+  })
+
+  const createValidRawPayload = (overrides: Partial<TransferPayload<ItemContent>> = {}): TransferPayload<ItemContent> => ({
+    uuid: '123e4567-e89b-12d3-a456-426614174000',
+    content_type: ContentType.TYPES.Note,
+    content: FillItemContent({}),
+    deleted: false,
+    updated_at: new Date('2023-01-01T12:00:00Z'),
+    created_at: new Date('2023-01-01T10:00:00Z'),
+    created_at_timestamp: 1672570800000,
+    updated_at_timestamp: 1672578000000,
+    ...overrides,
+  })
+
+  describe('constructor', () => {
+    it('should throw error when uuid is null', () => {
+      const rawPayload = createValidRawPayload({ uuid: null as any })
+      
+      expect(() => new TestPurePayload(rawPayload)).toThrow(
+        'Attempting to construct payload with null uuid'
+      )
+    })
+
+    it('should throw error when uuid is undefined', () => {
+      const rawPayload = createValidRawPayload({ uuid: undefined as any })
+      
+      expect(() => new TestPurePayload(rawPayload)).toThrow(
+        'Attempting to construct payload with null uuid'
+      )
+    })
+
+    it('should throw error when content type uses root key encryption but has key_system_identifier', () => {
+      const rawPayload = createValidRawPayload({
+        content_type: ContentType.TYPES.RootKey,
+        key_system_identifier: 'some-key-system-id'
+      })
+      
+      expect(() => new TestPurePayload(rawPayload)).toThrow(
+        'Rootkey-encrypted payload should not have a key system identifier'
+      )
+    })
+
+    it('should allow key_system_identifier for non-root-key content types', () => {
+      const rawPayload = createValidRawPayload({
+        content_type: ContentType.TYPES.Note,
+        key_system_identifier: 'some-key-system-id'
+      })
+      
+      expect(() => new TestPurePayload(rawPayload)).not.toThrow()
+    })
+
+    it('should set all properties correctly from raw payload', () => {
+      const rawPayload = createValidRawPayload({
+        uuid: 'test-uuid',
+        content_type: ContentType.TYPES.Note,
+        content: FillItemContent({ references: [] }),
+        deleted: true,
+        dirty: true,
+        duplicate_of: 'original-uuid',
+        user_uuid: 'user-uuid',
+        key_system_identifier: 'key-system-id',
+        shared_vault_uuid: 'vault-uuid',
+        last_edited_by_uuid: 'editor-uuid',
+        dirtyIndex: 5,
+        globalDirtyIndexAtLastSync: 3,
+        lastSyncBegan: new Date('2023-01-01T11:00:00Z'),
+        lastSyncEnd: new Date('2023-01-01T11:30:00Z'),
+      })
+
+      const payload = new TestPurePayload(rawPayload, PayloadSource.LocalDatabaseLoaded)
+
+      expect(payload.uuid).toBe('test-uuid')
+      expect(payload.content_type).toBe(ContentType.TYPES.Note)
+      expect(payload.content).toEqual(rawPayload.content)
+      expect(payload.deleted).toBe(true)
+      expect(payload.dirty).toBe(true)
+      expect(payload.duplicate_of).toBe('original-uuid')
+      expect(payload.user_uuid).toBe('user-uuid')
+      expect(payload.key_system_identifier).toBe('key-system-id')
+      expect(payload.shared_vault_uuid).toBe('vault-uuid')
+      expect(payload.last_edited_by_uuid).toBe('editor-uuid')
+      expect(payload.dirtyIndex).toBe(5)
+      expect(payload.globalDirtyIndexAtLastSync).toBe(3)
+      expect(payload.source).toBe(PayloadSource.LocalDatabaseLoaded)
+    })
+
+    it('should use default PayloadSource.Constructor when source is not provided', () => {
+      const rawPayload = createValidRawPayload()
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.source).toBe(PayloadSource.Constructor)
+    })
+
+    it('should call useBoolean for deleted field', () => {
+      const rawPayload = createValidRawPayload({ deleted: true })
+      mockUseBoolean.mockReturnValue(true)
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(mockUseBoolean).toHaveBeenCalledWith(true, false)
+      expect(payload.deleted).toBe(true)
+    })
+
+    it('should use false as default for deleted when undefined', () => {
+      const rawPayload = createValidRawPayload({ deleted: undefined })
+      mockUseBoolean.mockReturnValue(false)
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(mockUseBoolean).toHaveBeenCalledWith(undefined, false)
+      expect(payload.deleted).toBe(false)
+    })
+
+    it('should handle optional properties as undefined when not provided', () => {
+      const rawPayload = createValidRawPayload()
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.user_uuid).toBeUndefined()
+      expect(payload.key_system_identifier).toBeUndefined()
+      expect(payload.shared_vault_uuid).toBeUndefined()
+      expect(payload.last_edited_by_uuid).toBeUndefined()
+      expect(payload.dirty).toBeUndefined()
+      expect(payload.duplicate_of).toBeUndefined()
+      expect(payload.dirtyIndex).toBeUndefined()
+      expect(payload.globalDirtyIndexAtLastSync).toBeUndefined()
+    })
+
+    it('should schedule deepFreeze to be called', (done) => {
+      const rawPayload = createValidRawPayload()
+      const payload = new TestPurePayload(rawPayload)
+
+      setTimeout(() => {
+        expect(mockDeepFreeze).toHaveBeenCalledWith(payload)
+        done()
+      }, 10)
+    })
+  })
+
+  describe('date handling', () => {
+    it('should handle valid dates correctly', () => {
+      const createdAt = new Date('2023-01-01T10:00:00Z')
+      const updatedAt = new Date('2023-01-01T12:00:00Z')
+      const rawPayload = createValidRawPayload({
+        created_at: createdAt,
+        updated_at: updatedAt,
+        created_at_timestamp: createdAt.getTime(),
+        updated_at_timestamp: updatedAt.getTime(),
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.created_at).toEqual(createdAt)
+      expect(payload.updated_at).toEqual(updatedAt)
+      expect(payload.created_at_timestamp).toBe(createdAt.getTime())
+      expect(payload.updated_at_timestamp).toBe(updatedAt.getTime())
+    })
+
+    it('should handle negative updated_at dates by resetting to epoch', () => {
+      const rawPayload = createValidRawPayload({
+        updated_at: new Date(-1000),
+        updated_at_timestamp: -1000,
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.updated_at).toEqual(new Date(0))
+      expect(payload.updated_at_timestamp).toBe(0)
+    })
+
+    it('should handle negative created_at dates by using updated_at values', () => {
+      const updatedAt = new Date('2023-01-01T12:00:00Z')
+      const rawPayload = createValidRawPayload({
+        created_at: new Date(-1000),
+        created_at_timestamp: -1000,
+        updated_at: updatedAt,
+        updated_at_timestamp: updatedAt.getTime(),
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.created_at).toEqual(updatedAt)
+      expect(payload.created_at_timestamp).toBe(updatedAt.getTime())
+    })
+
+    it('should use current date for created_at when not provided', () => {
+      const rawPayload = createValidRawPayload({
+        created_at: undefined as any,
+        created_at_timestamp: undefined as any,
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.created_at).toBeInstanceOf(Date)
+      expect(payload.created_at.getTime()).toBeGreaterThan(0)
+    })
+
+    it('should use epoch date for updated_at when not provided', () => {
+      const rawPayload = createValidRawPayload({
+        updated_at: undefined as any,
+        updated_at_timestamp: undefined as any,
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.updated_at).toEqual(new Date(0))
+      expect(payload.updated_at_timestamp).toBe(0)
+    })
+
+    it('should handle sync dates correctly', () => {
+      const syncBegan = new Date('2023-01-01T11:00:00Z')
+      const syncEnd = new Date('2023-01-01T11:30:00Z')
+      const rawPayload = createValidRawPayload({
+        lastSyncBegan: syncBegan,
+        lastSyncEnd: syncEnd,
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.lastSyncBegan).toEqual(syncBegan)
+      expect(payload.lastSyncEnd).toEqual(syncEnd)
+    })
+
+    it('should handle undefined sync dates', () => {
+      const rawPayload = createValidRawPayload({
+        lastSyncBegan: undefined,
+        lastSyncEnd: undefined,
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.lastSyncBegan).toBeUndefined()
+      expect(payload.lastSyncEnd).toBeUndefined()
+    })
+  })
+
+  describe('ejected method', () => {
+    it('should return comprehensive TransferPayload', () => {
+      const rawPayload = createValidRawPayload({
+        uuid: 'test-uuid',
+        content_type: ContentType.TYPES.Note,
+        content: FillItemContent({ references: [] }),
+        deleted: true,
+        dirty: true,
+        duplicate_of: 'original-uuid',
+        user_uuid: 'user-uuid',
+        key_system_identifier: 'key-system-id',
+        shared_vault_uuid: 'vault-uuid',
+        last_edited_by_uuid: 'editor-uuid',
+        dirtyIndex: 5,
+        globalDirtyIndexAtLastSync: 3,
+        lastSyncBegan: new Date('2023-01-01T11:00:00Z'),
+        lastSyncEnd: new Date('2023-01-01T11:30:00Z'),
+      })
+
+      const payload = new TestPurePayload(rawPayload)
+      const ejected = payload.ejected()
+
+      expect(ejected.uuid).toBe('test-uuid')
+      expect(ejected.content_type).toBe(ContentType.TYPES.Note)
+      expect(ejected.content).toEqual(rawPayload.content)
+      expect(ejected.deleted).toBe(true)
+      expect(ejected.dirty).toBe(true)
+      expect(ejected.duplicate_of).toBe('original-uuid')
+      expect(ejected.user_uuid).toBe('user-uuid')
+      expect(ejected.key_system_identifier).toBe('key-system-id')
+      expect(ejected.shared_vault_uuid).toBe('vault-uuid')
+      expect(ejected.last_edited_by_uuid).toBe('editor-uuid')
+      expect(ejected.dirtyIndex).toBe(5)
+      expect(ejected.globalDirtyIndexAtLastSync).toBe(3)
+      expect(ejected.lastSyncBegan).toEqual(new Date('2023-01-01T11:00:00Z'))
+      expect(ejected.lastSyncEnd).toEqual(new Date('2023-01-01T11:30:00Z'))
+    })
+
+    it('should include undefined values in ejected payload', () => {
+      const rawPayload = createValidRawPayload()
+      const payload = new TestPurePayload(rawPayload)
+      const ejected = payload.ejected()
+
+      expect(ejected.user_uuid).toBeUndefined()
+      expect(ejected.key_system_identifier).toBeUndefined()
+      expect(ejected.shared_vault_uuid).toBeUndefined()
+      expect(ejected.last_edited_by_uuid).toBeUndefined()
+      expect(ejected.dirty).toBeUndefined()
+      expect(ejected.duplicate_of).toBeUndefined()
+      expect(ejected.dirtyIndex).toBeUndefined()
+      expect(ejected.globalDirtyIndexAtLastSync).toBeUndefined()
+    })
+  })
+
+  describe('getters', () => {
+    it('should return correct serverUpdatedAt', () => {
+      const updatedAt = new Date('2023-01-01T12:00:00Z')
+      const rawPayload = createValidRawPayload({ updated_at: updatedAt })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.serverUpdatedAt).toEqual(updatedAt)
+    })
+
+    it('should return correct serverUpdatedAtTimestamp', () => {
+      const timestamp = 1672578000000
+      const rawPayload = createValidRawPayload({ updated_at_timestamp: timestamp })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.serverUpdatedAtTimestamp).toBe(timestamp)
+    })
+  })
+
+  describe('signature data', () => {
+    it('should handle signature data correctly', () => {
+      const signatureData: PersistentSignatureData = {
+        signature: 'test-signature',
+        publicKey: 'test-public-key',
+      } as any
+
+      const rawPayload = createValidRawPayload({ signatureData })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.signatureData).toEqual(signatureData)
+    })
+
+    it('should handle undefined signature data', () => {
+      const rawPayload = createValidRawPayload({ signatureData: undefined })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.signatureData).toBeUndefined()
+    })
+  })
+
+  describe('error handling', () => {
+    it('should include content_type in error message when uuid is null', () => {
+      const rawPayload = createValidRawPayload({
+        uuid: null as any,
+        content_type: ContentType.TYPES.Note,
+      })
+
+      expect(() => new TestPurePayload(rawPayload)).toThrow(
+        /Content type: Note/
+      )
+    })
+  })
+
+  describe('edge cases', () => {
+    it('should handle empty string content', () => {
+      const rawPayload = createValidRawPayload({ content: '' })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.content).toBe('')
+    })
+
+    it('should handle string content', () => {
+      const rawPayload = createValidRawPayload({ content: 'encrypted-content' })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.content).toBe('encrypted-content')
+    })
+
+    it('should handle zero timestamps', () => {
+      const rawPayload = createValidRawPayload({
+        created_at_timestamp: 0,
+        updated_at_timestamp: 0,
+      })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.created_at_timestamp).toBe(0)
+      expect(payload.updated_at_timestamp).toBe(0)
+    })
+
+    it('should handle null/undefined nullish coalescing correctly', () => {
+      const rawPayload = createValidRawPayload({
+        user_uuid: null as any,
+        key_system_identifier: null as any,
+        shared_vault_uuid: null as any,
+        last_edited_by_uuid: null as any,
+      })
+      const payload = new TestPurePayload(rawPayload)
+
+      expect(payload.user_uuid).toBeUndefined()
+      expect(payload.key_system_identifier).toBeUndefined()
+      expect(payload.shared_vault_uuid).toBeUndefined()
+      expect(payload.last_edited_by_uuid).toBeUndefined()
+    })
+  })
+}) 
\ No newline at end of file
diff --git a/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.ts b/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.ts
index b2fc5d474e3..492cfe08645 100644
--- a/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.ts
+++ b/packages/models/src/Domain/Abstract/Payload/Implementations/PurePayload.ts
@@ -65,7 +65,7 @@ export abstract class PurePayload<T extends TransferPayload<C>, C extends ItemCo
     this.updated_at = new Date(rawPayload.updated_at || 0)
     this.updated_at_timestamp = rawPayload.updated_at_timestamp || 0
 
-    if (this.updated_at_timestamp < 0) {
+    if (this.updated_at < new Date(0) || this.updated_at_timestamp < 0) {
       this.updated_at_timestamp = 0
       this.updated_at = new Date(0)
     }
@@ -73,7 +73,7 @@ export abstract class PurePayload<T extends TransferPayload<C>, C extends ItemCo
     this.created_at = new Date(rawPayload.created_at || new Date())
     this.created_at_timestamp = rawPayload.created_at_timestamp || 0
 
-    if (this.created_at_timestamp < 0) {
+    if (this.created_at < new Date(0) || this.created_at_timestamp < 0) {
       this.created_at_timestamp = this.updated_at_timestamp
       this.created_at = this.updated_at
     }