Real-time clock with millisecond precision, Unix timestamp ↔ date conversion with Apple NSDate.timeIntervalSince1970 Double format support, and Swift / Objective-C API examples. All processing is local in your browser.

Notes:

• Current time: refreshes every 50ms, millisecond precision, showing Unix seconds / milliseconds / Apple Double alongside ISO 8601
• Timestamp → Date: auto-detects format (10-digit seconds / 13-digit milliseconds / Apple Double with decimal like 1692800123.456), outputs local time, UTC, ISO 8601
• Date → Timestamp: pick date and time (optional milliseconds), outputs Unix seconds / milliseconds / Apple Double
• Code examples: Swift and Objective-C APIs for getting timestamps, converting timestamps to Date, formatting strings, ISO8601