diff --git a/Packages/Persistence/README.md b/Packages/Persistence/README.md
index 7a0a8e9..b45defa 100644
--- a/Packages/Persistence/README.md
+++ b/Packages/Persistence/README.md
@@ -8,6 +8,7 @@ The [Fluent](https://github.com/hummingbird-project/hummingbird-fluent)-based da
 | Service | `Service`, which builds the `Fluent` service configured for the chosen driver |
 | Migrations | `PrepareDB`, the single registrar declaring every migration, in order |
 | Readiness | `Probe`, which reports whether the default database answers a `SELECT 1` within a deadline |
+| Accounts | `AccountRepository`, which finds an account by email or creates it, returning a `User` snapshot; `CreateUser` seeds the prototype's demo accounts |
 | Catalogue | `CatalogueRepository`, returning `Shop` and `Listing` snapshots narrowed and ordered by a `ListingFilter`; `SeedCatalogue` fills it with the prototype's demo data |
 
 ## Design rules
@@ -29,12 +30,12 @@ Sources/
 ├── Public/
 │   ├── Enumerations/      Driver, TLS
 │   ├── Methods/           Service, PrepareDB, Probe
-│   ├── Models/            Shop, Listing, ListingFilter
-│   ├── Repositories/      CatalogueRepository
+│   ├── Models/            Shop, Listing, ListingFilter, User
+│   ├── Repositories/      CatalogueRepository, AccountRepository
 │   └── Types/             Configuration
 └── Internal/
-    ├── Migrations/        CreateShop, CreateListing, SeedCatalogue
-    ├── Models/            ShopRecord, ListingRecord
+    ├── Migrations/        CreateShop, CreateListing, SeedCatalogue, CreateUser
+    ├── Models/            ShopRecord, ListingRecord, UserRecord
     └── Seeds/             Seed
 Tests/
 ├── Cases/                 the test suites, mirroring the Sources/ layout
diff --git a/Packages/Persistence/Sources/Internal/Migrations/CreateUser.swift b/Packages/Persistence/Sources/Internal/Migrations/CreateUser.swift
new file mode 100644
index 0000000..67241d0
--- /dev/null
+++ b/Packages/Persistence/Sources/Internal/Migrations/CreateUser.swift
@@ -0,0 +1,26 @@
+import FluentKit
+
+/// Creates and drops the `users` table backing ``UserRecord``, seeded with the prototype's demo accounts.
+struct CreateUser: AsyncMigration {
+
+    // MARK: Methods
+
+    func prepare(on database: Database) async throws {
+        try await database.schema(UserRecord.schema)
+            .id()
+            .field("email", .string, .required)
+            .field("display_name", .string, .required)
+            .unique(on: "email")
+            .create()
+
+        for account in Seed.accounts {
+            try await UserRecord(email: account.email, displayName: account.displayName).save(on: database)
+        }
+    }
+
+    func revert(on database: Database) async throws {
+        try await database.schema(UserRecord.schema)
+            .delete()
+    }
+
+}
diff --git a/Packages/Persistence/Sources/Internal/Models/UserRecord.swift b/Packages/Persistence/Sources/Internal/Models/UserRecord.swift
new file mode 100644
index 0000000..ddf36d4
--- /dev/null
+++ b/Packages/Persistence/Sources/Internal/Models/UserRecord.swift
@@ -0,0 +1,55 @@
+import FluentKit
+import Foundation
+
+/// A FluentKit model of a single `users` row.
+final class UserRecord: Model, @unchecked Sendable {
+
+    // MARK: Properties
+
+    static let schema = "users"
+
+    @ID(key: .id)
+    var id: UUID?
+
+    @Field(key: "email")
+    var email: String
+
+    @Field(key: "display_name")
+    var displayName: String
+
+    // MARK: Initializers
+
+    init() {}
+
+    /// Creates a record with the given values.
+    /// - Parameters:
+    ///   - email: the account's normalized email address.
+    ///   - displayName: the name other people see.
+    init(
+        email: String,
+        displayName: String
+    ) {
+        self.email = email
+        self.displayName = displayName
+    }
+
+}
+
+// MARK: - Extensions
+
+extension UserRecord {
+
+    // MARK: Computed
+
+    /// The `Sendable` snapshot of the saved record.
+    var snapshot: User {
+        get throws {
+            .init(
+                id: try requireID(),
+                email: email,
+                displayName: displayName
+            )
+        }
+    }
+
+}
diff --git a/Packages/Persistence/Sources/Internal/Seeds/Seed.swift b/Packages/Persistence/Sources/Internal/Seeds/Seed.swift
index 01cd584..9273f24 100644
--- a/Packages/Persistence/Sources/Internal/Seeds/Seed.swift
+++ b/Packages/Persistence/Sources/Internal/Seeds/Seed.swift
@@ -5,6 +5,12 @@ enum Seed {
 
     // MARK: Constants
 
+    /// The demo accounts: the buyer the stubbed passkey signs in, then a seller.
+    static let accounts: [(email: String, displayName: String)] = [
+        ("mara.v@example.com", "Mara Visser"),
+        ("joost@kestrelrow.example", "Joost de Wit"),
+    ]
+
     /// The demo listings, newest first.
     static let listings: [Listing] = [
         single(
diff --git a/Packages/Persistence/Sources/Public/Methods/PrepareDB.swift b/Packages/Persistence/Sources/Public/Methods/PrepareDB.swift
index 7aa60db..6c7a33b 100644
--- a/Packages/Persistence/Sources/Public/Methods/PrepareDB.swift
+++ b/Packages/Persistence/Sources/Public/Methods/PrepareDB.swift
@@ -25,6 +25,7 @@ public struct PrepareDB: Sendable {
             CreateShop(),
             CreateListing(),
             SeedCatalogue(),
+            CreateUser(),
         ])
     }
 
diff --git a/Packages/Persistence/Sources/Public/Models/User.swift b/Packages/Persistence/Sources/Public/Models/User.swift
new file mode 100644
index 0000000..f32eed6
--- /dev/null
+++ b/Packages/Persistence/Sources/Public/Models/User.swift
@@ -0,0 +1,27 @@
+import Foundation
+
+/// A `Sendable` snapshot of an account.
+public struct User: Sendable, Equatable {
+
+    // MARK: Properties
+
+    /// The account's identifier.
+    public let id: UUID
+    /// The account's normalized email address.
+    public let email: String
+    /// The name other people see.
+    public let displayName: String
+
+    // MARK: Initializers
+
+    public init(
+        id: UUID,
+        email: String,
+        displayName: String
+    ) {
+        self.id = id
+        self.email = email
+        self.displayName = displayName
+    }
+
+}
diff --git a/Packages/Persistence/Sources/Public/Repositories/AccountRepository.swift b/Packages/Persistence/Sources/Public/Repositories/AccountRepository.swift
new file mode 100644
index 0000000..7a4baf5
--- /dev/null
+++ b/Packages/Persistence/Sources/Public/Repositories/AccountRepository.swift
@@ -0,0 +1,53 @@
+import FluentKit
+import HummingbirdFluent
+
+/// Reads and creates accounts through the default database.
+public struct AccountRepository: Sendable {
+
+    // MARK: Constants
+
+    /// The email of the demo buyer the prototype's stubbed passkey signs in.
+    public static let demoEmail = Seed.accounts[0].email
+
+    // MARK: Properties
+
+    private let fluent: Fluent
+
+    // MARK: Initializers
+
+    /// Creates a repository backed by the given `Fluent` service.
+    /// - Parameter fluent: the service whose default database the repository operates on.
+    public init(
+        fluent: Fluent
+    ) {
+        self.fluent = fluent
+    }
+
+    // MARK: Methods
+
+    /// Fetches the account with the given email, creating it when there is none: one step both signs in and joins.
+    ///
+    /// A new account is named after the email's local part until its owner picks a display name.
+    /// - Parameter email: the account's normalized email address.
+    /// - Returns: the account, existing or new.
+    public func account(
+        email: String
+    ) async throws -> User {
+        if let record = try await UserRecord.query(on: fluent.db())
+            .filter(\.$email == email)
+            .first()
+        {
+            return try record.snapshot
+        }
+
+        let record = UserRecord(
+            email: email,
+            displayName: String(email.prefix { $0 != "@" })
+        )
+
+        try await record.save(on: fluent.db())
+
+        return try record.snapshot
+    }
+
+}
diff --git a/Packages/Persistence/Tests/Cases/Public/Repositories/AccountRepositoryTests.swift b/Packages/Persistence/Tests/Cases/Public/Repositories/AccountRepositoryTests.swift
new file mode 100644
index 0000000..25b219e
--- /dev/null
+++ b/Packages/Persistence/Tests/Cases/Public/Repositories/AccountRepositoryTests.swift
@@ -0,0 +1,35 @@
+import Testing
+
+@testable import Persistence
+
+@Suite(
+    "AccountRepository repository",
+    .tags(.repository)
+)
+struct AccountRepositoryTests {
+
+    // MARK: Methods tests
+
+    @Test
+    func `finds the seeded demo buyer`() async throws {
+        try await withDatabase { fluent in
+            let user = try await AccountRepository(fluent: fluent).account(email: AccountRepository.demoEmail)
+
+            #expect(user.email == "mara.v@example.com")
+            #expect(user.displayName == "Mara Visser")
+        }
+    }
+
+    @Test
+    func `joins an unknown email once, named after its local part`() async throws {
+        try await withDatabase { fluent in
+            let repository = AccountRepository(fluent: fluent)
+            let joined = try await repository.account(email: "sam@example.com")
+            let returning = try await repository.account(email: "sam@example.com")
+
+            #expect(joined.displayName == "sam")
+            #expect(returning == joined)
+        }
+    }
+
+}
diff --git a/Packages/Persistence/Tests/Cases/Public/Repositories/CatalogueRepositoryTests.swift b/Packages/Persistence/Tests/Cases/Public/Repositories/CatalogueRepositoryTests.swift
index 7d2dbc1..b2c893b 100644
--- a/Packages/Persistence/Tests/Cases/Public/Repositories/CatalogueRepositoryTests.swift
+++ b/Packages/Persistence/Tests/Cases/Public/Repositories/CatalogueRepositoryTests.swift
@@ -78,27 +78,13 @@ struct CatalogueRepositoryTests {
 
 private extension CatalogueRepositoryTests {
 
-    /// Runs the body against a migrated, seeded in-memory catalogue, shutting the pool down after.
+    /// Runs the body against a migrated, seeded in-memory catalogue.
     func withCatalogue(
         _ body: (CatalogueRepository) async throws -> Void
     ) async throws {
-        let fluent = try Service(
-            driver: .inMemory,
-            logger: Logger(label: "test")
-        )()
-
-        do {
-            await PrepareDB()(for: fluent)
-
-            try await fluent.migrate()
-            try await body(.init(fluent: fluent))
-        } catch {
-            try? await fluent.shutdown()
-
-            throw error
+        try await withDatabase {
+            try await body(.init(fluent: $0))
         }
-
-        try await fluent.shutdown()
     }
 
 }
diff --git a/Packages/Persistence/Tests/Utils/Methods/WithDatabase.swift b/Packages/Persistence/Tests/Utils/Methods/WithDatabase.swift
new file mode 100644
index 0000000..435d334
--- /dev/null
+++ b/Packages/Persistence/Tests/Utils/Methods/WithDatabase.swift
@@ -0,0 +1,27 @@
+import HummingbirdFluent
+import Logging
+
+@testable import Persistence
+
+/// Runs the body against a migrated, seeded in-memory database, shutting the pool down after — even on failure, or the pool asserts on `deinit`.
+func withDatabase(
+    _ body: (Fluent) async throws -> Void
+) async throws {
+    let fluent = try Service(
+        driver: .inMemory,
+        logger: Logger(label: "test")
+    )()
+
+    do {
+        await PrepareDB()(for: fluent)
+
+        try await fluent.migrate()
+        try await body(fluent)
+    } catch {
+        try? await fluent.shutdown()
+
+        throw error
+    }
+
+    try await fluent.shutdown()
+}