ImportError: cannot import name 'mock_dynamodb' from 'moto'

TL;DR: moto 5 deleted the per-service decorators like mockdynamodb. Replace `from moto import mockdynamodb with from moto import mockaws`, and swap the @mockdynamodb decorator for @mock_aws.

from moto import mock_dynamodb
E   ImportError: cannot import name 'mock_dynamodb' from 'moto'

Fix it

1. Change the import: from moto import mock_aws. Expected: imports cleanly.
2. Change decorators: @mockaws instead of @mockdynamodb (it mocks all services). Expected: tests pass.
3. Grep the suite for other removed decorators: mocks3, mocksqs, mockssm all became mockaws. Expected: none left.
4. If you must stay on old decorators short-term: pip install "moto<5". Expected: mock_dynamodb works again, but you miss fixes.

When this applies

• The import of mockdynamodb (or mocks3, mock_sqs, ...) fails and moto is 5.x.

When it doesn't

• moto is 4.x: the old decorators exist; something else is wrong.
• The import works but mocks do nothing: check decorator placement and scope.

Compatibility

• moto >= 5.0. For 1.x-4.x, mock_dynamodb still exists.

Why it happens

moto unified dozens of per-service decorators into one mock_aws to simplify maintenance. The old names were removed, not deprecated, in 5.0.

Edge cases

• mock_aws mocks every service, which can surprise tests that relied on unmocked calls failing; scope tests accordingly.
• The breaking-change list lives in moto's release docs; check it before any major moto upgrade.

Reported in GitHub (gh:department-of-veterans-affairs/notification-api#1624): ImportError: cannot import name 'mockdynamodb' from 'moto' after moto 5 upgrade. The verified fix: Upgrading to moto 5 broke test suites with ImportError: cannot import name 'mockdynamodb' from 'moto' (alongside mocks3 and mockssm). The cause: moto 5 replaced every per-service decorator with a single mockaws. Fix: from moto import mockaws and decorate with @mock_aws. Source: the linked GitHub issue. Source: https://github.com/department-of-veterans-affairs/notification-api/issues/1624 Thread ref: gh:department-of-veterans-affairs/notification-api#1624