Temporal is a microservice orchestration platform which enables developers to build scalable applications without sacrificing productivity or reliability. Temporal server executes units of application logic, Workflows, in a resilient manner that automatically handles intermittent failures, and retries failed operations.

Cadence is a distributed, scalable, durable, and highly available orchestration engine we developed at Uber Engineering to execute asynchronous long-running business logic in a scalable and resilient way.

Conductor is an orchestration engine that runs in the cloud.
Netflix built Conductor to help orchestrate microservices based process flows with the following features:

Allow creating complex process / business flows in which individual task is implemented by a microservice.
A JSON DSL based blueprint defines the execution flow.
Provide visibility and traceability into the these process flows.
Expose control semantics around pause, resume, restart, etc allowing for better devops experience.
Allow greater reuse of existing microservices providing an easier path for onboarding.
User interface to visualize the process flows.
Ability to synchronously process all the tasks when needed.
Ability to scale millions of concurrently running process flows.
Backed by a queuing service abstracted from the clients.
Be able to operate on HTTP or other transports e.g. gRPC.