What is @Sendable in Swift?

@Sendable marks closures or functions safe to send across concurrency domains like actors and Tasks. Ensures captures are Sendable and by value.

How do I fix 'captured var in concurrent code' error?

Use capture lists like `[x]` to snapshot vars. Make captures Sendable — no mutable classes.

Yes, for data isolation. Doesn't handle reentrancy; pair with actor rules.

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Swift's @Sendable attribute turns risky closures into concurrency-safe workhorses. It's the guardrail your actors have been begging for.

theAIcatchup Apr 10, 2026 4 min read

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#@Sendable #Actor Isolation #Concurrency #Sendable protocol #Swift #Swift Closures #Swift Concurrency #actors #closures #data isolation

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