BOUNDARY INSPECTOR
What Survives the Membrane?
Push JavaScript values through serialization boundaries and watch what survives, what mutates, and what silently disappears.
Most bugs aren't in the logic — they're at the boundaries. This tool maps every membrane in the web platform so you never get surprised by a Date becoming a string again.
Select Membrane
The most common serialization boundary. Rigid. Only JSON-safe types survive.
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JSON
Result Detail
Select a value to inspect
Legend
✓Survived
~Coerced
✕Destroyed
!Throws
WHY THIS MATTERS
Every time data crosses a boundary — server to client, component to embed, app to storage — it passes through a serialization membrane. Most bugs aren't in the logic. They're at the boundaries. A Date that becomes a string. A Map that becomes {}. A function that silently disappears. Model the membrane before writing the code.