Camunda

Camunda is the enterprise standard for BPMN-based process orchestration — visual process design in BPMN, execution with audit trail, and integration with external services via Job Workers. For agents: deploy BPMN process definitions, start process instances (trigger workflows), complete user tasks (approve/reject human steps), query running/completed instances, and implement Job Workers (agents that execute service tasks in process flows). Camunda 8 uses Zeebe (cloud-native, gRPC) while Camunda 7 uses traditional REST. Both are widely deployed. Confidence is docs-derived.

Camunda 8 REST API at api.cloud.camunda.io (Cloud) or {self-hosted}/v1. Processes: POST /v1/process-definitions/search finds deployed processes. POST /v1/process-instances creates instance ({processDefinitionKey, variables: {...}}). GET /v1/process-instances/{key} retrieves instance. POST /v1/process-instances/{key}/cancel cancels. User tasks: POST /v1/user-tasks/search queries pending tasks. POST /v1/user-tasks/{key}/complete completes ({variables: {...}}). POST /v1/user-tasks/{key}/assign assigns to user. Job workers (Zeebe): implement worker that polls specific job type, executes task, completes job. Message correlation: POST /v1/messages/correlation sends message to waiting process instance. Incidents: GET /v1/incidents lists active incidents (process errors).

Camunda 8 Cloud: OAuth2 client credentials — POST /oauth/token ({client_id, client_secret, audience}) → Bearer token. Cloud console for credentials. Self-hosted: no auth by default — add Identity component for production. Zeebe gRPC: mTLS for production cluster communication. HTTPS enforced on Cloud. Process variables: JSON objects passed at instance creation and throughout execution. Worker auth: same OAuth2 token for job completion API calls.

Process instance errors: incident created if service task fails — investigate via GET /v1/incidents. Job workers: poll model — implement retry logic in worker. User task SLA: no built-in timeout — implement timer events in BPMN. Camunda Cloud uptime at status.camunda.io. Self-hosted: operator-managed. Zeebe gRPC: high-throughput alternative to REST for process instances. BPMN complexity: visual process design in Camunda Modeler reduces implementation errors. Large process instances: variable size limits (1MB per instance).

docs.camunda.io covers REST API reference, Zeebe client guides (Java, Go, .NET, Rust), BPMN modeling guide, and deployment documentation. Getting started: Camunda 8 free plan, Camunda Modeler for BPMN design, first process deployed in under 15 minutes. Official Java client (Spring Zeebe), community Node.js client. Community via Camunda Forum (forum.camunda.io) and GitHub. Comprehensive documentation for a complex process orchestration platform.