Security

Use this page when a JavaScript/TypeScript reader accepts bytes from outside the application's trust boundary. Fory reconstructs application values; it does not authenticate the sender, protect transport integrity, or decide whether a valid value is authorized for a business operation.

Application boundary

Before deserialization:

• Authenticate the sender and protect message integrity at the transport or storage layer.
• Enforce request or file size, timeout, and concurrency limits outside Fory.
• Register only the application types the endpoint accepts and configure the reader before its first root operation.
• Validate the deserialized value against application authorization and domain rules before use.

Built-in safeguards

Security-related configuration:

• Register only the expected schemas before deserializing untrusted payloads.
• Set maxDepth for the maximum nesting depth your service accepts.
• Set maxGraphMemoryBytes as an approximate gate for collection, map, array, struct, and object-heavy payloads. It is not an exact heap cap; leaf values are gated by remaining input bytes.
• Keep maxTypeFields and maxTypeMetaBytes at their defaults unless the data is not malicious and a trusted peer sends larger remote metadata.
• Keep maxSchemaVersionsPerType and maxAverageSchemaVersionsPerType at their defaults unless the data is not malicious and a trusted peer sends many remote schema versions.
• Prefer explicit Type.struct(...) schemas over Type.any() for untrusted input.
• Pass hps only from the official package version you deploy with Fory.

Verification

Add negative tests for the boundary as well as normal round trips. Verify that the configured reader rejects unexpected application types, excessive nesting, resource-limit violations, and malformed input. After a failed read, verify that a valid root can still be read with the same Fory instance.

See Configuration for the complete option reference and Type Registration for the Fory registration API.