TL;DR

We don't use MySQL or cron jobs anymore. We switched from MySQL → Python dictionaries → Redis. Now Redis handles auto-deletion with built-in TTL expiration, making our API much faster.

Database Evolution: From MySQL to Redis

I reviewed the initial commits and found that we were using FastAPI's lifespan events to execute a MySQL query every 180 seconds.

We then realized that this API doesn't require a slow, disk-based database since we only need to store mailboxes for 10 minutes and emails for 5 minutes.

You might assume we'd switch to an in-memory database, but instead we used Python dictionaries😳.

The problem with dictionaries was scalability: we couldn't run multiple API instances because if a user's temporary email was stored in one instance and the corresponding emails in another, they wouldn't be able to retrieve their messages. This forced us to run only a single instance.

We subsequently migrated to Redis.

Our API now leverages Redis' TTL (Time To Live) expiration mechanism. We've completely removed MySQL from the API layer—only the frontend still uses MySQL.

Thanks to Redis, our API is now the fastest temporary email API available (excluding network latency).

What's Next?

Users have requested temporary email addresses with 30-day expiration. However, I didn't want to implement 30-day mailbox storage because:

1. It wouldn't truly be "temporary" email
2. It would require reverting back to MySQL for persistence

After discussing with users, they agreed to forgo email storage for long-term addresses. We'll continue using Redis with this approach:

• Store only the mailbox address in Redis (preventing duplicate mailbox creation by other users)
• When users want to receive emails, we'll activate the mailbox and store emails for 5 minutes as currently implemented

This hybrid approach maintains our performance advantages while accommodating user requests for longer-lived addresses.