Security

Use this page when a Dart 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 generated models before deserializing untrusted payloads.
• Use checkStructVersion: true with compatible: false for intentional same-schema payloads.
• Set maxDepth to reject unexpectedly deep payload shapes.
• Keep maxGraphMemoryBytes at the default for most inputs, or set an explicit positive byte gate for known trusted collection/map/struct-heavy payloads.
• Keep the remote schema metadata limits at their defaults unless the data is not malicious and a trusted peer sends larger metadata or many schema versions.
• Prefer generated schemas and explicit field metadata over broad dynamic fields for untrusted input.

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.