| Sumn | Temporal | |
|---|---|---|
| What it is | A control plane for background agents. Playbooks are versioned DAGs you can read, run and audit. | A durable execution SDK and cluster. Workflows are code your engineers write and operate. |
| Durability | Runs checkpoint at every stage. A crash or deploy resumes the run where it stopped. | The reference implementation. Event-sourced workflow state, replay on failure.On this dimension the two agree more than they differ. |
| Agent workloads | Built for them. Each stage runs in a fresh isolated VM with its own kernel, destroyed after. | Possible, with assembly. You build sandboxing, model routing and output contracts yourself. |
| Spend control | Budgets are enforced by the platform per run and per playbook. A run that hits its cap pauses warm and asks. | Not a platform concept. Cost control lives in whatever your workflow code does. |
| Human oversight | Gates are first-class. Judged gates apply your written criteria; held gates wait for a person. Everything else lands in one attention inbox. | Signals and queries exist as primitives. The review surface is yours to build. |
| Who can own it | Anyone who can write a checklist can read a playbook. Ops and business processes are peers to code. | Engineers. It's a developer tool by design, and a good one. |
| Multi-model support | Bring your own keys. Anthropic, OpenAI, Google, and any OpenAI-compatible endpoint, in the same playbook. | Model calls are just activities. Routing, fallback and key isolation are your code. |
Where Temporal is strong
- Durable execution for arbitrary code, at serious scale, with years of production hardening behind it.
- A programming model your backend engineers may already know, with SDKs across the major languages.
- Total flexibility. If you can write it, Temporal can make it durable. No platform opinions to fit inside.
If your engineers want to write durable workflows as code and you have the team to build the operational shell around them, Temporal is excellent and you should use it. Sumn is for the company that wants the shell itself. Isolation, budgets, gates and the audit record ship as the product, so the person who owns a process can own its playbook without owning infrastructure.
Is Sumn built on Temporal?
No. Sumn runs its own durable execution layer. Runs checkpoint at stage boundaries and resume after a crash or deploy, which is the property that matters.
Can Sumn and Temporal coexist?
Yes, and they often should. Keep your engineering-owned workflows in Temporal and put the processes people babysit by hand, like triage, review panels and reporting, on Sumn playbooks.
Do I need engineers to write a playbook?
You need someone who can describe the process precisely. Playbooks are versioned data with a real editor, not application code. Engineers usually write the first one and stop being the bottleneck after that.
See how Sumn runs a playbook →The homepage has a live run you can watch. No signup.