How do you avoid accidentally running independent asynchronous operations sequentially with await?

Direct answer

If operations are independent, start them before awaiting or coordinate them with a Promise combinator; awaiting each operation before starting the next creates sequential latency.

This code is sequential: const a = await fetchA(); const b = await fetchB();. fetchB() is not even started until fetchA() has completed.

For independent work, you can start both first: const pa = fetchA(); const pb = fetchB(); const [a,b] = await Promise.all([pa,pb]);. Total latency can then approach the slower operation rather than the sum of both latencies.

Use sequential awaits when the next operation genuinely depends on the previous result.
Use concurrent coordination for independent operations when the downstream system can safely handle the concurrency.
For hundreds or thousands of operations, unlimited Promise.all() may overload APIs, databases, memory, or rate limits; use bounded concurrency instead.