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The SessionStorage interface defines the contract that all session storage implementations must follow. This ensures consistent behavior across different database adapters.

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Interface Definition

From the source code at packages/apps/session-storage/shopify-app-session-storage/src/types.ts: 
import {Session} from '@shopify/shopify-api';

/**
 * Defines the strategy to be used to store sessions for the Shopify App.
 */
export interface SessionStorage {
  /**
   * Creates or updates the given session in storage.
   *
   * @param session Session to store
   */
  storeSession(session: Session): Promise<boolean>;

  /**
   * Loads a session from storage.
   *
   * @param id Id of the session to load
   */
  loadSession(id: string): Promise<Session | undefined>;

  /**
   * Deletes a session from storage.
   *
   * @param id Id of the session to delete
   */
  deleteSession(id: string): Promise<boolean>;

  /**
   * Deletes an array of sessions from storage.
   *
   * @param ids Array of session id's to delete
   */
  deleteSessions(ids: string[]): Promise<boolean>;

  /**
   * Return an array of sessions for a given shop (or [] if none found).
   *
   * @param shop shop of the session(s) to return
   */
  findSessionsByShop(shop: string): Promise<Session[]>;
}

​
Methods

​
storeSession

Creates or updates a session in storage.
​
session
Session
required
The session object to store. Contains all authentication and user data.
​
returns
Promise<boolean>
Returns true if the session was successfully stored, false otherwise.
Behavior:
  • If a session with the same id exists, it will be updated
  • If no session exists with that id, a new one will be created
  • This implements an “upsert” pattern (update or insert)
Example: 
const session = new Session({
  id: 'offline_example.myshopify.com',
  shop: 'example.myshopify.com',
  state: 'state-value',
  isOnline: false,
  accessToken: 'shpat_xxxxx',
  scope: 'read_products,write_orders'
});

const success = await sessionStorage.storeSession(session);
if (success) {
  console.log('Session stored successfully');
}

​
loadSession

Retrieves a session from storage by its ID.
​
id
string
required
The unique identifier of the session to load.
​
returns
Promise<Session | undefined>
Returns the Session object if found, or undefined if no session exists with that ID.
Session ID Format:
  • Offline sessions: offline_{shop}
  • Online sessions: {shop}_{userId}
Example: 
const session = await sessionStorage.loadSession(
  'offline_example.myshopify.com'
);

if (session) {
  console.log('Access token:', session.accessToken);
  console.log('Expires:', session.expires);
} else {
  console.log('Session not found');
}

​
deleteSession

Deletes a single session from storage.
​
id
string
required
The unique identifier of the session to delete.
​
returns
Promise<boolean>
Returns true if the session was successfully deleted, false otherwise.
Behavior:
  • Attempting to delete a non-existent session typically returns true
  • This method is idempotent (safe to call multiple times)
Example: 
// Delete session when user logs out or uninstalls app
const deleted = await sessionStorage.deleteSession(
  'offline_example.myshopify.com'
);

if (deleted) {
  console.log('Session deleted');
}

​
deleteSessions

Deletes multiple sessions in a single operation.
​
ids
string[]
required
Array of session IDs to delete.
​
returns
Promise<boolean>
Returns true if all sessions were successfully deleted, false otherwise.
Use Cases:
  • Cleaning up all sessions for a shop when app is uninstalled
  • Batch deletion of expired sessions
  • Removing all online sessions for a shop
Example: 
// Delete all sessions for a shop
const shopSessions = await sessionStorage.findSessionsByShop(
  'example.myshopify.com'
);

const sessionIds = shopSessions.map(session => session.id);
const deleted = await sessionStorage.deleteSessions(sessionIds);

if (deleted) {
  console.log(`Deleted ${sessionIds.length} sessions`);
}

​
findSessionsByShop

Finds all sessions associated with a specific shop.
​
shop
string
required
The shop domain (e.g., ‘example.myshopify.com’).
​
returns
Promise<Session[]>
Returns an array of Session objects. Returns an empty array if no sessions are found.
What It Returns:
  • Both online and offline sessions for the shop
  • Active and expired sessions (check expires field)
  • Sessions for all users who have accessed the app from that shop
Example: 
// Find all sessions for a shop
const sessions = await sessionStorage.findSessionsByShop(
  'example.myshopify.com'
);

console.log(`Found ${sessions.length} sessions`);

sessions.forEach(session => {
  console.log(`- ${session.id} (online: ${session.isOnline})`);
});

// Filter to only active sessions
const now = new Date();
const activeSessions = sessions.filter(
  session => !session.expires || session.expires > now
);

​
Implementation Guidelines

If you’re implementing a custom session storage adapter, follow these guidelines:

​
Thread Safety

Implementations should be safe for concurrent access. Multiple requests may attempt to read/write sessions simultaneously.

​
Error Handling

Implementations should:
  • Catch database errors and log them appropriately
  • Return false on storage/deletion failures rather than throwing
  • Return undefined from loadSession on errors, not throw

​
Performance Considerations

  • Index the shop column for efficient findSessionsByShop queries
  • Use upsert operations in storeSession to avoid race conditions
  • Implement connection pooling for database adapters
  • Consider caching for frequently accessed sessions

​
Data Serialization

Different storage backends require different serialization:
Store each session property as a separate column:
// Convert Session to row data
const entries = session.toPropertyArray(true);

// Handle expires conversion (milliseconds to seconds)
if (row.expires) {
  row.expires = Math.floor(row.expires / 1000);
}

​
Deserialization

When loading sessions, reconstruct the Session object: 
// From property array (for JSON storage)
const session = Session.fromPropertyArray(propertyArray, true);

// From object (for document storage)
const session = new Session(sessionObject);

​
Testing Your Implementation

The SDK provides testing utilities: 
import {batteryOfTests} from '@shopify/shopify-app-session-storage-test-utils';
import {MyCustomSessionStorage} from './my-storage';

describe('MyCustomSessionStorage', () => {
  batteryOfTests(async () => new MyCustomSessionStorage());
});
The batteryOfTests function runs a comprehensive test suite that verifies your implementation correctly handles all SessionStorage methods.

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Additional Interfaces

​
RdbmsSessionStorageOptions

Configuration for relational database adapters: 
interface RdbmsSessionStorageOptions {
  sessionTableName: string;
  migratorOptions?: RdbmsSessionStorageMigratorOptions;
}
​
sessionTableName
string
default:"shopify_sessions"
Name of the table to store sessions.
​
migratorOptions
RdbmsSessionStorageMigratorOptions
Configuration for the migration system.

​
SessionStorageMigrator

Handles database migrations for session storage: 
interface SessionStorageMigrator {
  initMigrationPersistence(): Promise<void>;
  hasMigrationBeenApplied(migrationName: string): Promise<boolean>;
  saveAppliedMigration(migrationName: string): Promise<void>;
  getMigrationList(): MigrationOperation[];
  applyMigrations(databaseReady: Promise<void>): Promise<void>;
}
Most users don’t need to interact with the migrator directly. It runs automatically when initializing RDBMS-based storage adapters.

Database Adapters

Setup guides for each official adapter

Session Storage Overview

Learn about session storage concepts

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