FIFO

First-in-first-out — the default, fairest ordering: whoever arrived first is served first.

Why we need this / what value this brings

Simple, predictable, and fair — no item can starve indefinitely as long as new items don't arrive faster than they're processed.

When to use this

The default choice for any queue unless there's a specific reason to deviate (urgency, staleness).

How to use or implement this

Most managed queue services (SQS standard, RabbitMQ default) are FIFO by default — just don't build custom logic that accidentally reorders processing.

Research questions

• Is Localz's notification/email queue processed FIFO, and does that matter for correctness (e.g. must a 'booking created' event always process before 'booking confirmed')?

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Empty folder — drop notes, links, and findings here as you research.