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Developer Tools · head to head

Restate vs Swagger UI

Restate logo

Restate

Developer Tools

Durable execution engine in Rust with a free tier and low-latency workflows

From
Free
Rated
-
Full reviewWebsite
Swagger UI logo

Swagger UI

Developer Tools

Interactive API documentation generated from OpenAPI specs

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Restate the runtime is under a Business Source Licence rather than an open source licence, so building a competing managed offering on it is prohibited and some procurement functions will reject it on licence grounds alone.; Swagger UI only as good as the specification: a thin OpenAPI file produces thin documentation
  • They diverge on capability: Restate covers Durable execution, Swagger UI covers OpenAPI rendering.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Restate and Swagger UI actually diverge.

Attributes where Restate and Swagger UI differ
AttributeRestateSwagger UI
Pricing modelPer month by durable action countOpen source, no licence fee
PlatformsLinux, macOS, WebWeb, Self-hosted, Docker

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Developer Tools).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Restate

  • Durable execution
  • Virtual objects
  • Single binary runtime
  • Multi-language SDKs
  • Workflows and sagas
  • Restate Cloud

Only in Swagger UI

  • OpenAPI rendering
  • Try it out
  • Schema display
  • Self-hostable

What people use each for

The jobs each tool is most often brought in to do.

Restate

  • Payment or order flows where a crash between two external API calls must not double-charge or lose the ordernot Swagger UI
  • AI agent loops that call tools over minutes or hours and must survive a deployment mid-runnot Swagger UI
  • Replacing hand-rolled retry, idempotency key and outbox code across a set of microservicesnot Swagger UI
  • A small team that wants durable workflows without operating a Temporal cluster and its databasenot Swagger UI

Swagger UI

  • Publishing API documentation that stays in step with the specificationnot Restate
  • Letting developers try endpoints before writing any client codenot Restate
  • Internal API discovery across teamsnot Restate

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Restate

  • The runtime is under a Business Source Licence rather than an open source licence, so building a competing managed offering on it is prohibited and some procurement functions will reject it on licence grounds alone.
  • Restate Cloud jumps from a free fifty thousand actions straight to 300 US dollars a month for twenty million, so a workload sitting at a few hundred thousand actions pays enterprise-shaped money for hobby-shaped volume.
  • It is a young project against Temporal’s established base, so hiring engineers who already know it is unrealistic and the answer to most questions is in the docs rather than on Stack Overflow.
  • The programming model requires structuring code around durable handlers and virtual objects, which is a genuine rewrite for existing services rather than a library you add.
  • The single-binary simplicity that makes small deployments cheap also means fewer operational knobs at very large scale than a system designed as separable components.

Swagger UI

  • Only as good as the specification: a thin OpenAPI file produces thin documentation
  • Default presentation is dated compared with modern documentation tools
  • Large specifications render slowly and become hard to navigate
  • Try it out against production needs care with authentication and CORS, and is often disabled as a result

Pricing, plan by plan

Restate

Free
  • FreeFree
    • Fifty thousand durable actions per month
    • No credit card required
    • Community support
  • Starter$300/month
    • Twenty million actions per month
    • Two hundred actions per second, bursting to one thousand
    • Twenty GB storage
  • Pro$1000/month
    • Fifty million actions per month
    • Five hundred actions per second, bursting to two thousand
    • Fifty GB storage
  • Enterprise$undefined/year
    • Negotiated volume
    • Twenty-four seven P0 support
    • 99.99 per cent SLA

Swagger UI

Free
  • Swagger UIFree
    • Full functionality
    • Commercial use permitted
    • Community support

Which should you pick?

Choose Restate if

  • You need durable execution.
  • You want to start without paying.
  • You work on Linux, macOS, Web.
  • You also want virtual objects.
Restate review

Choose Swagger UI if

  • You need openapi rendering.
  • You want to start without paying.
  • You work on Web, Self-hosted, Docker.
  • You also want try it out.
Swagger UI review

Questions people ask

Is Restate or Swagger UI better?
Neither clearly leads. Restate starts at Free and Swagger UI at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Restate or Swagger UI?
Restate starts at Free and Swagger UI at Free.
Does Restate or Swagger UI run on more platforms?
Restate runs on Linux, macOS, Web. Swagger UI runs on Web, Self-hosted, Docker.
Can I use Restate for free?
Both have a free tier, so you can try either at no cost before committing.
What is Restate best used for?
Restate is most often used for payment or order flows where a crash between two external api calls must not double-charge or lose the order, ai agent loops that call tools over minutes or hours and must survive a deployment mid-run, replacing hand-rolled retry, idempotency key and outbox code across a set of microservices, a small team that wants durable workflows without operating a temporal cluster and its database. Of those, payment or order flows where a crash between two external api calls must not double-charge or lose the order and ai agent loops that call tools over minutes or hours and must survive a deployment mid-run are not what Swagger UI is typically brought in for.
What can Restate do that Swagger UI cannot?
Restate covers Durable execution, Virtual objects, Single binary runtime, Multi-language SDKs. Swagger UI covers OpenAPI rendering, Try it out, Schema display, Self-hostable.

Answered from the vendors’ own pages

Restate: Is Restate open source?

The SDKs are MIT. The runtime is under a Business Source Licence, which permits self-hosting but not offering it as a competing service.

Swagger UI: Is Swagger UI free?

Yes, open source under the Apache 2.0 licence. SmartBear sells commercial SwaggerHub separately.

Restate: How does it compare with Temporal?

Same problem, different shape: one Rust binary with embedded storage instead of a server plus database plus workers, and lower per-step latency.

Swagger UI: What is the difference between Swagger and OpenAPI?

OpenAPI is the specification format; Swagger is the toolset around it, including Swagger UI. The specification was renamed from Swagger to OpenAPI in 2016.

Restate: Is there a free tier?

Yes, fifty thousand durable actions a month on Restate Cloud with no card required.

Swagger UI: Can Swagger UI make real API calls?

Yes, through its try-it-out control, though authentication and CORS configuration often mean it is disabled for production APIs.

Restate: Which languages are supported?

TypeScript, Java, Kotlin, Go, Python and Rust.

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