diff --git a/lnbits/core/extensions/prototype.py b/lnbits/core/extensions/prototype.py
index 8aeafab4a..db1543e14 100644
--- a/lnbits/core/extensions/prototype.py
+++ b/lnbits/core/extensions/prototype.py
@@ -68,7 +68,8 @@ class InMemoryExtensionAPI(ExtensionAPI):
             wallet = await get_wallet(request.wallet_id)
             if wallet is None or wallet.user != self.user_id:
                 raise PermissionError(
-                    "Creating an invoice for this wallet requires an authenticated user context."
+                    "Creating an invoice for this wallet requires an "
+                    "authenticated user context."
                 )
         else:
             pass
diff --git a/lnbits/core/extensions/storage.py b/lnbits/core/extensions/storage.py
new file mode 100644
index 000000000..833e394a6
--- /dev/null
+++ b/lnbits/core/extensions/storage.py
@@ -0,0 +1,236 @@
+from __future__ import annotations
+
+import json
+import re
+from pathlib import Path
+from typing import Any
+
+from loguru import logger
+
+from lnbits.core.crud import update_migration_version
+from lnbits.core.db import db as core_db
+from lnbits.core.models import DbVersion
+from lnbits.core.models.extensions import InstallableExtension
+from lnbits.db import POSTGRES, SQLITE, Connection, Database
+
+_MIGRATION_FILE_RE = re.compile(r"^(\d+)_.*\.json$")
+_SQL_IDENTIFIER_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
+
+
+async def migrate_wasm_extension_database(
+    ext: InstallableExtension,
+    current_version: DbVersion | None = None,
+) -> None:
+    migrations_dir = ext.ext_dir / "storage" / "migrations"
+    migration_files = _migration_files(migrations_dir)
+    if not migration_files:
+        logger.debug(f"No storage migrations for WASM extension '{ext.id}'.")
+        return
+
+    ext_db = Database(f"ext_{ext.id}")
+    async with ext_db.connect() as conn:
+        for version, path in migration_files:
+            if current_version and version <= current_version.version:
+                continue
+            logger.debug(f"running WASM storage migration {ext.id}.{version}")
+            print(f"running migration {ext.id}.{version}")
+            await _run_storage_migration(conn, path)
+            await _update_wasm_migration_version(conn, ext.id, version)
+
+
+def _migration_files(migrations_dir: Path) -> list[tuple[int, Path]]:
+    if not migrations_dir.is_dir():
+        return []
+
+    files: list[tuple[int, Path]] = []
+    for path in migrations_dir.glob("*.json"):
+        match = _MIGRATION_FILE_RE.match(path.name)
+        if not match:
+            raise ValueError(f"Invalid WASM storage migration filename: {path.name}")
+        files.append((int(match.group(1)), path))
+    return sorted(files)
+
+
+async def _run_storage_migration(db: Connection, path: Path) -> None:
+    migration = _load_json(path)
+    operations = migration.get("operations")
+    if not isinstance(operations, list):
+        raise ValueError(f"WASM storage migration '{path}' has no operations list.")
+
+    for operation in operations:
+        if not isinstance(operation, dict):
+            raise ValueError(f"WASM storage migration '{path}' has invalid operation.")
+        sql = _operation_sql(db, operation)
+        await db.execute(sql)
+
+
+def _operation_sql(db: Connection, operation: dict[str, Any]) -> str:
+    op = operation.get("op")
+    if op == "create_table":
+        return _create_table_sql(db, operation)
+    if op == "add_field":
+        return _add_field_sql(db, operation)
+    if op == "create_index":
+        return _create_index_sql(db, operation)
+    raise ValueError(f"Unsupported WASM storage migration operation: {op}")
+
+
+def _create_table_sql(db: Connection, operation: dict[str, Any]) -> str:
+    table = _require_identifier(operation, "table")
+    fields = _require_fields(operation)
+    if not any(field.get("name") == "id" for field in fields):
+        raise ValueError(f"WASM storage table '{table}' must define an id field.")
+
+    columns = [
+        _column_sql(db, field, primary_key=field.get("name") == "id")
+        for field in fields
+    ]
+    return f"""
+        CREATE TABLE IF NOT EXISTS {_table_ref(db, table)} (
+            {", ".join(columns)}
+        );
+    """
+
+
+def _add_field_sql(db: Connection, operation: dict[str, Any]) -> str:
+    table = _require_identifier(operation, "table")
+    field = _field_from_add_field_operation(operation)
+    return f"""
+        ALTER TABLE {_table_ref(db, table)}
+        ADD COLUMN {_column_sql(db, field)};
+    """
+
+
+def _create_index_sql(db: Connection, operation: dict[str, Any]) -> str:
+    table = _require_identifier(operation, "table")
+    name = _require_identifier(operation, "name")
+    field = _require_identifier(operation, "field")
+
+    if db.type == SQLITE and db.schema:
+        return f"""
+            CREATE INDEX IF NOT EXISTS {_schema_ref(db, name)}
+            ON {table} ({field});
+        """
+
+    return f"""
+        CREATE INDEX IF NOT EXISTS {name}
+        ON {_table_ref(db, table)} ({field});
+    """
+
+
+def _column_sql(
+    db: Connection,
+    field: dict[str, Any],
+    *,
+    primary_key: bool = False,
+) -> str:
+    name = _require_identifier(field, "name")
+    column_type = _field_type_sql(db, field)
+    parts = [name, column_type]
+
+    if primary_key:
+        parts.append("PRIMARY KEY")
+    elif not field.get("nullable", False):
+        parts.append("NOT NULL")
+
+    if "default" in field:
+        parts.append(f"DEFAULT {_default_sql(field['default'])}")
+
+    return " ".join(parts)
+
+
+def _field_type_sql(db: Connection, field: dict[str, Any]) -> str:
+    if field.get("list") is True:
+        return "TEXT"
+
+    field_type = field.get("type")
+    if field_type == "string":
+        return "TEXT"
+    if field_type == "integer":
+        return db.big_int
+    if field_type == "number":
+        return "DOUBLE PRECISION" if db.type == POSTGRES else "REAL"
+    if field_type == "boolean":
+        return "BOOLEAN"
+    if field_type == "datetime":
+        return "TIMESTAMP"
+    raise ValueError(f"Unsupported WASM storage field type: {field_type}")
+
+
+def _default_sql(value: Any) -> str:
+    if value is None:
+        return "NULL"
+    if isinstance(value, bool):
+        return "true" if value else "false"
+    if isinstance(value, int | float):
+        return str(value)
+    if isinstance(value, str):
+        return _quote_sql_string(value)
+    if isinstance(value, list | dict):
+        return _quote_sql_string(json.dumps(value))
+    raise ValueError(f"Unsupported WASM storage default value: {value}")
+
+
+def _field_from_add_field_operation(operation: dict[str, Any]) -> dict[str, Any]:
+    field = {
+        "name": operation.get("field"),
+        "type": operation.get("type"),
+    }
+    for key in ("default", "list", "nullable"):
+        if key in operation:
+            field[key] = operation[key]
+    return field
+
+
+def _require_fields(operation: dict[str, Any]) -> list[dict[str, Any]]:
+    fields = operation.get("fields")
+    if not isinstance(fields, list) or not fields:
+        raise ValueError("WASM storage create_table operation requires fields.")
+    if not all(isinstance(field, dict) for field in fields):
+        raise ValueError("WASM storage fields must be objects.")
+    return fields
+
+
+def _require_identifier(data: dict[str, Any], key: str) -> str:
+    value = data.get(key)
+    if not isinstance(value, str) or not _SQL_IDENTIFIER_RE.match(value):
+        raise ValueError(f"Invalid WASM storage SQL identifier for '{key}': {value}")
+    return value
+
+
+def _table_ref(db: Connection, table: str) -> str:
+    if db.schema:
+        return f"{_schema_ref(db, table)}"
+    return table
+
+
+def _schema_ref(db: Connection, name: str) -> str:
+    if not db.schema:
+        return name
+    if not _SQL_IDENTIFIER_RE.match(db.schema):
+        raise ValueError(f"Invalid WASM extension storage schema: {db.schema}")
+    return f"{db.schema}.{name}"
+
+
+def _quote_sql_string(value: str) -> str:
+    return "'" + value.replace("'", "''") + "'"
+
+
+def _load_json(path: Path) -> dict[str, Any]:
+    with open(path, encoding="utf-8") as json_file:
+        data = json.load(json_file)
+    if not isinstance(data, dict):
+        raise ValueError(f"WASM storage migration '{path}' must be a JSON object.")
+    return data
+
+
+async def _update_wasm_migration_version(
+    db: Connection,
+    ext_id: str,
+    version: int,
+) -> None:
+    if db.schema is None:
+        await update_migration_version(db, ext_id, version)
+    else:
+        async with core_db.connect() as conn:
+            await update_migration_version(conn, ext_id, version)
diff --git a/lnbits/core/helpers.py b/lnbits/core/helpers.py
index 6b1d408c9..bd7c84f1e 100644
--- a/lnbits/core/helpers.py
+++ b/lnbits/core/helpers.py
@@ -14,6 +14,7 @@ from lnbits.core.crud import (
 )
 from lnbits.core.db import db as core_db
 from lnbits.core.extensions.loader import is_wasm_extension_id
+from lnbits.core.extensions.storage import migrate_wasm_extension_database
 from lnbits.core.models import DbVersion
 from lnbits.core.models.extensions import InstallableExtension
 from lnbits.db import COCKROACH, POSTGRES, SQLITE, Connection
@@ -24,7 +25,7 @@ async def migrate_extension_database(
     ext: InstallableExtension, current_version: DbVersion | None = None
 ):
     if is_wasm_extension_id(ext.id):
-        logger.debug(f"Skipping Python migrations for WASM extension '{ext.id}'.")
+        await migrate_wasm_extension_database(ext, current_version)
         return
 
     try:
@@ -109,10 +110,6 @@ async def migrate_databases():
     await load_disabled_extension_list()
 
     for ext in await get_installed_extensions():
-        if is_wasm_extension_id(ext.id):
-            logger.debug(f"Skipping Python migrations for WASM extension '{ext.id}'.")
-            continue
-
         current_version = next(
             (v for v in current_versions if v.db == ext.id),
             DbVersion(db=ext.id, version=0),