feat(snap-account-service): add SnapAccountService

.github/CODEOWNERS

@@ -13,6 +13,7 @@
 /packages/account-tree-controller            @MetaMask/accounts-engineers
 /packages/profile-sync-controller            @MetaMask/accounts-engineers
 /packages/money-account-controller           @MetaMask/accounts-engineers
+/packages/snap-account-service               @MetaMask/accounts-engineers
 
 ## Assets Team
 /packages/assets-controllers         @MetaMask/metamask-assets
@@ -232,3 +233,5 @@
 /packages/money-account-controller/CHANGELOG.md @MetaMask/accounts-engineers @MetaMask/core-platform
 /packages/chomp-api-service/package.json @MetaMask/earn @MetaMask/delegation @MetaMask/core-platform
 /packages/chomp-api-service/CHANGELOG.md @MetaMask/earn @MetaMask/delegation @MetaMask/core-platform
+/packages/snap-account-service/package.json @MetaMask/accounts-engineers @MetaMask/core-platform
+/packages/snap-account-service/CHANGELOG.md @MetaMask/accounts-engineers @MetaMask/core-platform

README.md

@@ -93,6 +93,7 @@ Each package in this repository has its own README where you can find installati
 - [`@metamask/selected-network-controller`](packages/selected-network-controller)
 - [`@metamask/shield-controller`](packages/shield-controller)
 - [`@metamask/signature-controller`](packages/signature-controller)
+- [`@metamask/snap-account-service`](packages/snap-account-service)
 - [`@metamask/social-controllers`](packages/social-controllers)
 - [`@metamask/storage-service`](packages/storage-service)
 - [`@metamask/subscription-controller`](packages/subscription-controller)
@@ -181,6 +182,7 @@ linkStyle default opacity:0.5
   selected_network_controller(["@metamask/selected-network-controller"]);
   shield_controller(["@metamask/shield-controller"]);
   signature_controller(["@metamask/signature-controller"]);
+  snap_account_service(["@metamask/snap-account-service"]);
   social_controllers(["@metamask/social-controllers"]);
   storage_service(["@metamask/storage-service"]);
   subscription_controller(["@metamask/subscription-controller"]);
@@ -487,6 +489,7 @@ linkStyle default opacity:0.5
   signature_controller --> logging_controller;
   signature_controller --> messenger;
   signature_controller --> network_controller;
+  snap_account_service --> messenger;
   social_controllers --> base_controller;
   social_controllers --> base_data_service;
   social_controllers --> controller_utils;

packages/snap-account-service/CHANGELOG.md

@@ -0,0 +1,14 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- Add `SnapAccountService` ([#8414](https://github.com/MetaMask/core/pull/8414))
+
+[Unreleased]: https://github.com/MetaMask/core/

packages/snap-account-service/LICENSE

@@ -0,0 +1,20 @@
+MIT License
+
+Copyright (c) 2026 MetaMask
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

packages/snap-account-service/README.md

@@ -0,0 +1,25 @@
+# `@metamask/snap-account-service`
+
+Service for Account Management Snaps
+
+## Overview
+
+`SnapAccountService` centralizes common operations around Snap-based account management, providing a single integration point for:
+
+- **Migration** — Migrates accounts from the legacy monolithic v1 Snap keyring to per-Snap v2 keyrings. The migration runs once at initialization and is safe for concurrent callers (subsequent calls await the same promise).
+- **Readiness** — Ensures a Snap is fully ready for account operations before proceeding: migration is complete, a v2 keyring exists for the Snap, and the Snap platform itself is initialized.
+- **Keyring message handling** — Routes messages from Snap keyrings to the appropriate per-Snap keyring instance, including lazy keyring creation for event-driven v1 flows.
+
+The service exposes its functionality through the MetaMask messenger pattern and depends on `KeyringController` and `SnapController`.
+
+## Installation
+
+`yarn add @metamask/snap-account-service`
+
+or
+
+`npm install @metamask/snap-account-service`
+
+## Contributing
+
+This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).

packages/snap-account-service/jest.config.js

@@ -0,0 +1,26 @@
+/*
+ * For a detailed explanation regarding each configuration property and type check, visit:
+ * https://jestjs.io/docs/configuration
+ */
+
+const merge = require('deepmerge');
+const path = require('path');
+
+const baseConfig = require('../../jest.config.packages');
+
+const displayName = path.basename(__dirname);
+
+module.exports = merge(baseConfig, {
+  // The display name when running multiple projects
+  displayName,
+
+  // An object that configures minimum threshold enforcement for coverage results
+  coverageThreshold: {
+    global: {
+      branches: 100,
+      functions: 100,
+      lines: 100,
+      statements: 100,
+    },
+  },
+});

packages/snap-account-service/package.json

@@ -0,0 +1,73 @@
+{
+  "name": "@metamask/snap-account-service",
+  "version": "0.0.0",
+  "description": "Service for Account Management Snaps",
+  "keywords": [
+    "Ethereum",
+    "MetaMask"
+  ],
+  "homepage": "https://github.com/MetaMask/core/tree/main/packages/snap-account-service#readme",
+  "bugs": {
+    "url": "https://github.com/MetaMask/core/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/MetaMask/core.git"
+  },
+  "license": "MIT",
+  "sideEffects": false,
+  "exports": {
+    ".": {
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
+      }
+    },
+    "./package.json": "./package.json"
+  },
+  "main": "./dist/index.cjs",
+  "types": "./dist/index.d.cts",
+  "files": [
+    "dist/"
+  ],
+  "scripts": {
+    "build": "ts-bridge --project tsconfig.build.json --verbose --clean --no-references",
+    "build:all": "ts-bridge --project tsconfig.build.json --verbose --clean",
+    "build:docs": "typedoc",
+    "changelog:update": "../../scripts/update-changelog.sh @metamask/snap-account-service",
+    "changelog:validate": "../../scripts/validate-changelog.sh @metamask/snap-account-service",
+    "messenger-action-types:check": "tsx ../../packages/messenger-cli/src/cli.ts --check",
+    "messenger-action-types:generate": "tsx ../../packages/messenger-cli/src/cli.ts --generate",
+    "since-latest-release": "../../scripts/since-latest-release.sh",
+    "test": "NODE_OPTIONS=--experimental-vm-modules jest --reporters=jest-silent-reporter",
+    "test:clean": "NODE_OPTIONS=--experimental-vm-modules jest --clearCache",
+    "test:verbose": "NODE_OPTIONS=--experimental-vm-modules jest --verbose",
+    "test:watch": "NODE_OPTIONS=--experimental-vm-modules jest --watch"
+  },
+  "dependencies": {
+    "@metamask/messenger": "^1.1.1"
+  },
+  "devDependencies": {
+    "@metamask/auto-changelog": "^6.1.0",
+    "@ts-bridge/cli": "^0.6.4",
+    "@types/jest": "^29.5.14",
+    "deepmerge": "^4.2.2",
+    "jest": "^29.7.0",
+    "ts-jest": "^29.2.5",
+    "tsx": "^4.20.5",
+    "typedoc": "^0.25.13",
+    "typedoc-plugin-missing-exports": "^2.0.0",
+    "typescript": "~5.3.3"
+  },
+  "engines": {
+    "node": "^18.18 || >=20"
+  },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org/"
+  }
+}

packages/snap-account-service/src/SnapAccountService.test.ts

@@ -0,0 +1,76 @@
+import { Messenger, MOCK_ANY_NAMESPACE } from '@metamask/messenger';
+import type {
+  MockAnyNamespace,
+  MessengerActions,
+  MessengerEvents,
+} from '@metamask/messenger';
+
+import type { SnapAccountServiceMessenger } from './SnapAccountService';
+import { SnapAccountService } from './SnapAccountService';
+
+/**
+ * The type of the messenger populated with all external actions and events
+ * required by the service under test.
+ */
+type RootMessenger = Messenger<
+  MockAnyNamespace,
+  MessengerActions<SnapAccountServiceMessenger>,
+  MessengerEvents<SnapAccountServiceMessenger>
+>;
+
+/**
+ * Constructs the root messenger for the service under test.
+ *
+ * @returns The root messenger.
+ */
+function getRootMessenger(): RootMessenger {
+  return new Messenger({ namespace: MOCK_ANY_NAMESPACE });
+}
+
+/**
+ * Constructs the messenger for the service under test.
+ *
+ * @param rootMessenger - The root messenger.
+ * @returns The service-specific messenger.
+ */
+function getMessenger(
+  rootMessenger: RootMessenger,
+): SnapAccountServiceMessenger {
+  return new Messenger({
+    namespace: 'SnapAccountService',
+    parent: rootMessenger,
+  });
+}
+
+/**
+ * Constructs the service under test with sensible defaults.
+ *
+ * @param args - The arguments to this function.
+ * @param args.options - The options that the service constructor takes.
+ * @returns The new service, root messenger, and service messenger.
+ */
+function setup({
+  options = {},
+}: {
+  options?: Partial<ConstructorParameters<typeof SnapAccountService>[0]>;
+} = {}): {
+  service: SnapAccountService;
+  rootMessenger: RootMessenger;
+  messenger: SnapAccountServiceMessenger;
+} {
+  const rootMessenger = getRootMessenger();
+  const messenger = getMessenger(rootMessenger);
+  const service = new SnapAccountService({ messenger, ...options });
+
+  return { service, rootMessenger, messenger };
+}
+
+describe('SnapAccountService', () => {
+  describe('init', () => {
+    it('resolves without throwing', async () => {
+      const { service } = setup();
+
+      expect(await service.init()).toBeUndefined();
+    });
+  });
+});

packages/snap-account-service/src/SnapAccountService.ts

@@ -0,0 +1,78 @@
+import type { Messenger } from '@metamask/messenger';
+
+/**
+ * The name of the {@link SnapAccountService}, used to namespace the service's
+ * actions and events.
+ */
+export const serviceName = 'SnapAccountService';
+
+/**
+ * All of the methods within {@link SnapAccountService} that are exposed via
+ * the messenger.
+ */
+const MESSENGER_EXPOSED_METHODS = [] as const;
+
+/**
+ * Actions that {@link SnapAccountService} exposes to other consumers.
+ */
+export type SnapAccountServiceActions = never;
+
+/**
+ * Actions from other messengers that {@link SnapAccountService} calls.
+ */
+type AllowedActions = never;
+
+/**
+ * Events that {@link SnapAccountService} exposes to other consumers.
+ */
+export type SnapAccountServiceEvents = never;
+
+/**
+ * Events from other messengers that {@link SnapAccountService} subscribes to.
+ */
+type AllowedEvents = never;
+
+/**
+ * The messenger which is restricted to actions and events accessed by
+ * {@link SnapAccountService}.
+ */
+export type SnapAccountServiceMessenger = Messenger<
+  typeof serviceName,
+  SnapAccountServiceActions | AllowedActions,
+  SnapAccountServiceEvents | AllowedEvents
+>;
+
+/**
+ * Service responsible for managing account management snaps.
+ */
+export class SnapAccountService {
+  /**
+   * The name of the service.
+   */
+  readonly name: typeof serviceName;
+
+  readonly #messenger: SnapAccountServiceMessenger;
+
+  /**
+   * Constructs a new {@link SnapAccountService}.
+   *
+   * @param args - The constructor arguments.
+   * @param args.messenger - The messenger suited for this service.
+   */
+  constructor({ messenger }: { messenger: SnapAccountServiceMessenger }) {
+    this.name = serviceName;
+    this.#messenger = messenger;
+
+    this.#messenger.registerMethodActionHandlers(
+      this,
+      MESSENGER_EXPOSED_METHODS,
+    );
+  }
+
+  /**
+   * Initializes the snap account service.
+   */
+  async init(): Promise<void> {
+    // TODO: Add initialization logic here.
+  }
+}

packages/snap-account-service/src/index.ts

@@ -0,0 +1,6 @@
+export { SnapAccountService } from './SnapAccountService';
+export type {
+  SnapAccountServiceActions,
+  SnapAccountServiceEvents,
+  SnapAccountServiceMessenger,
+} from './SnapAccountService';

packages/snap-account-service/tsconfig.build.json

@@ -0,0 +1,10 @@
+{
+  "extends": "../../tsconfig.packages.build.json",
+  "compilerOptions": {
+    "baseUrl": "./",
+    "outDir": "./dist",
+    "rootDir": "./src"
+  },
+  "references": [{ "path": "../messenger/tsconfig.build.json" }],
+  "include": ["../../types", "./src"]
+}

packages/snap-account-service/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.packages.json",
+  "compilerOptions": {
+    "baseUrl": "./"
+  },
+  "references": [{ "path": "../messenger" }],
+  "include": ["../../types", "./src"]
+}

packages/snap-account-service/typedoc.json

@@ -0,0 +1,7 @@
+{
+  "entryPoints": ["./src/index.ts"],
+  "excludePrivate": true,
+  "hideGenerator": true,
+  "out": "docs",
+  "tsconfig": "./tsconfig.build.json"
+}

teams.json

@@ -77,5 +77,6 @@
   "metamask/remote-feature-flag-controller": "team-extension-platform,team-mobile-platform",
   "metamask/storage-service": "team-extension-platform,team-mobile-platform",
   "metamask/config-registry-controller": "team-networks",
-  "metamask/money-account-controller": "team-accounts-framework"
+  "metamask/money-account-controller": "team-accounts-framework",
+  "metamask/snap-account-service": "team-accounts-framework"
 }