Strongly-Typed Domain Keys

Technical Preview

The C# SDK is a technical preview available from Camunda 8.9. It will become fully supported in Camunda 8.10. Its API surface may change in future releases without following semver.

All domain identifiers (process definition keys, job keys, user task keys, etc.) are readonly record struct types rather than plain strings. This prevents accidentally mixing different key types at compile time — the same pattern as the JS SDK's branded types.

using Camunda.Orchestration.Sdk;

// Lift a raw value into the correct nominal type
var defKey = ProcessDefinitionKey.AssumeExists("2251799813686749");

// Type safety — compiler prevents mixing key types
var taskKey = UserTaskKey.AssumeExists("123456");
// await client.GetProcessDefinitionAsync(taskKey); // ← compile error

// Validation — constraints (pattern, length) checked at construction
ProcessDefinitionKey.IsValid("2251799813686749"); // true

// Values returned from API calls are already typed
var result = await client.GetProcessDefinitionAsync(defKey);
// result.ProcessDefinitionKey is ProcessDefinitionKey, not string

// Transparent JSON serialization — no special handling needed

Key types implement ICamundaKey (string-backed) or ICamundaLongKey (long-backed) and serialize as plain JSON values. Constraint validation (regex pattern, min/max length) is enforced in AssumeExists() and queryable via IsValid().