Developer Criticizes AWS Cognito for Documentation and SDK Inconsistencies

Challenges with AWS Cognito Implementation

A developer encountered significant difficulties while setting up authentication for a startup using AWS Cognito. Despite previous experience with other authentication systems like Auth0 and Firebase Auth, the developer found Cognito's implementation process problematic. The decision to use Cognito was influenced by its integration within the AWS ecosystem and its free tier for the first 50,000 monthly active users.

Documentation Inconsistencies and Lack of Clarity

A primary issue identified was the quality of AWS Cognito's documentation. The developer described it as fragmented, attempting to serve diverse audiences from enterprise architects to frontend and mobile developers, resulting in a lack of clear, linear guidance. Specific searches, such as for custom attribute validation, often led to pages assuming prior knowledge not readily available.

The documentation also contained inconsistent code examples, mixing outdated JavaScript SDK versions, Amplify v1 API references, and raw AWS SDK examples without clear version indications. This forced the developer to spend time deciphering which examples were relevant to their current setup.

Breaking Changes in Amplify JavaScript SDK

Further complications arose with the Amplify JavaScript SDK. The developer initially built the authentication flow using Amplify v5. However, a subsequent update to Amplify v6 introduced breaking changes, altering method signatures and causing unexpected issues. This required rework and highlighted a lack of backward compatibility or clear migration paths within the SDK.

Overall Developer Experience

The developer concluded that the combination of confusing documentation and unstable SDK versions made AWS Cognito a frustrating choice for startup authentication. The experience led to regret over the initial decision, despite the perceived benefits of being within the AWS ecosystem and the cost-free user tier.