Production checklist

Last reviewed Jun 1, 2026 Content v20260601

Track mode

server_compiled

Means

Compiled runner

Reading

~2 min

Level

advanced

This lesson

This lesson teaches Production checklist: the syntax, patterns, and safety habits you need before advancing in Swift.

Teams still ship Production checklist in Swift codebases—skipping it leaves gaps in debugging and code reviews.

You will apply Production checklist in contexts like: iPhone/iPad/Mac apps, server-side Swift (niche), and Apple toolchain projects.

Write Swift in main.swift with print(), click Run on server—the dev runner swiftc compiles and runs the binary (requires Swift toolchain, typically macOS; LEARNING_RUNNER_ENABLED=true).

When pointers, structs, and basic control flow from intermediate lessons are familiar.

Shipping Swift apps means more than correct syntax—configure static analysis, tests, crash reporting, accessibility, App Store compliance, and concurrency discipline for iOS and macOS releases.

Checklist

Enable Swift strict concurrency checking and fix data-race warnings before release
SwiftLint or SwiftFormat in CI; treat analyzer warnings as debt with a burn-down plan
swift test and XCTest UI suites on every PR; device tests before major releases
Pin Xcode and Swift versions in CI; document minimum OS deployment targets
Structured logging (os.Logger) and crash reporting—not raw print() in production
Review retain cycles in view controllers and closures; use Instruments locally
Privacy manifests, App Transport Security, and keychain for secrets
Accessibility labels, Dynamic Type, and localization early—not bolted on at ship

Important interview questions and answers

Q: Why SwiftLint in CI?
A: Enforces style and common mistakes the compiler misses—consistent APIs and safer patterns across teams.
Q: print() in production?
A: Avoid—use unified logging with privacy redaction and log levels; print lacks filtering and hurts performance.

Self-check

Name two tools for Swift static analysis or formatting.
Why avoid print in App Store builds?

Track summary

You covered Swift from syntax and optionals through collections, structs and classes, protocols, extensions, generics, errors, closures, property wrappers, concurrency, ARC, modules, SPM, file I/O, testing, Codable, SwiftUI context, and interview habits. Swift’s sweet spot is native Apple platform apps—iOS, macOS, and shared packages—with safe types and protocol-oriented design.

Next steps

Build a small SPM CLI or library with swift test
Create a SwiftUI app in Xcode and ship to TestFlight
Practice async/await networking with URLSession locally
Compare patterns with Kotlin, Java, and JavaScript tracks
Read Apple’s Swift documentation on concurrency and data race safety

Tip: This lesson closes the track with summary and next steps—run SwiftLint and swift test before shipping.

Interview prep

SwiftLint in CI?: Enforces style and catches patterns compiler misses.
print in production?: Avoid—use os.Logger with privacy and levels.

Playground

Runs on the configured server runner (dev: npm run runner with LEARNING_RUNNER_ENABLED=true). Output appears below the editor.

Code runner not available

Server runner is disabled. Set LEARNING_RUNNER_ENABLED=true and LEARNING_RUNNER_URL in .env (see .env.example).

Discussion

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Starter discussion topics

SwiftLint CI?
TestFlight next?

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