Snapshot Format

Reference for full snapshot JSON payloads consumed at the boundary.

Top-Level Shape

{
  "meta": {
    "version": "2026-02-23.1",
    "generatedAtEpochMillis": 1766800000000,
    "source": "s3://flags/app-snapshot.json"
  },
  "flags": [
    {
      "key": "feature::app::checkoutVariant",
      "defaultValue": { "type": "ENUM", "value": "CLASSIC", "enumClassName": "com.example.CheckoutVariant" },
      "salt": "v1",
      "isActive": true,
      "rampUpAllowlist": [],
      "rules": []
    }
  ]
}

Fields

Field	Type	Required	Notes
meta	object	No	Optional metadata for provenance and versioning.
meta.version	string	No	Logical config revision string.
meta.generatedAtEpochMillis	number	No	UTC epoch milliseconds from publisher.
meta.source	string	No	Source identifier (URI, commit, artifact ref).
flags	array	Yes	Full set of feature definitions for namespace scope.
flags[].key	string	Yes	Feature identifier; must resolve against namespace schema.
flags[].defaultValue	object	Yes	Tagged value object (BOOLEAN, INT, DOUBLE, STRING, ENUM, DATA_CLASS).
flags[].salt	string	Yes	Salt used for deterministic bucketing.
flags[].isActive	boolean	Yes	If false, evaluation returns default regardless of rules.
flags[].rampUpAllowlist	array<string>	No	Stable IDs that bypass rollout gate for this feature.
flags[].rules	array	Yes	Ordered rule payloads evaluated by deterministic precedence.

Value Variants

Variant	Shape
Boolean	{ "type": "BOOLEAN", "value": true }
Int	{ "type": "INT", "value": 3 }
Double	{ "type": "DOUBLE", "value": 0.5 }
String	{ "type": "STRING", "value": "text" }
Enum	{ "type": "ENUM", "value": "CLASSIC", "enumClassName": "com.example.CheckoutVariant" }
Data class	{ "type": "DATA_CLASS", "dataClassName": "com.example.Policy", "value": { ... } }

Boundary Semantics

• Successful decode/load materializes trusted configuration.
• Invalid shape or unresolved feature keys return typed ParseError through Result.failure.
• Failed loads do not partially mutate active runtime state.

Next Steps

• Patch Format - Incremental update payloads.
• Snapshot Load Options - Strict vs. forward-compatible loading strategies.