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Developer Tools · head to head

Restate vs Unit21

Restate logo

Restate

Developer Tools

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

From
Free
Free plan
Yes
Full reviewWebsite
Unit21 logo

Unit21

Cybersecurity

No-code fraud and AML risk operations platform for fintechs and neobanks

From
On request
Free plan
No
Full reviewWebsite

The short version

  • Only Restate has a free tier, so it costs nothing to try first.
  • 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.; Unit21 it is built for fintech scale rather than card issuer scale, so organisations reaching very high transaction volumes generally re-evaluate against heavier platforms and face a migration.
  • They diverge on capability: Restate covers Durable execution, Unit21 covers No-code rule builder.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Restate and Unit21 actually diverge.

Attributes where Restate and Unit21 differ
AttributeRestateUnit21
Starting priceFreeOn request
Pricing modelPer month by durable action countquote
Free tierYesNo
PlatformsLinux, macOS, WebWeb
CategoryDeveloper ToolsCybersecurity

Identical on both: user rating (Not yet rated).

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 Unit21

  • No-code rule builder
  • Case management
  • SAR filing
  • Backtesting
  • Identity and device signals
  • Data ingestion API

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 Unit21
  • AI agent loops that call tools over minutes or hours and must survive a deployment mid-runnot Unit21
  • Replacing hand-rolled retry, idempotency key and outbox code across a set of microservicesnot Unit21
  • A small team that wants durable workflows without operating a Temporal cluster and its databasenot Unit21

Unit21

  • A neobank whose sponsor bank requires a documented monitoring programme before it will keep the BIN sponsorshipnot Restate
  • A crypto exchange needing SAR filing and case management without building an internal compliance engineering teamnot Restate
  • A payments startup where the fraud lead needs to ship a new rule the same day a new attack pattern appearsnot Restate
  • A lender consolidating fraud alerts from three point tools into one investigator queue with a single audit trailnot 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.

Unit21

  • It is built for fintech scale rather than card issuer scale, so organisations reaching very high transaction volumes generally re-evaluate against heavier platforms and face a migration.
  • No-code rule authoring shifts power to the risk team, which is the point, but without governance it produces rule sprawl that nobody can explain to an examiner two years later.
  • Detection quality depends on the signals you feed it, so a thin integration produces thin results and the platform cannot compensate with proprietary consortium data the way larger vendors do.
  • Pricing is quoted by volume with an annual commitment, so a fintech whose growth stalls pays for headroom it did not use.
  • SAR filing coverage is oriented to United States FinCEN reporting, so firms filing in the United Kingdom, European Union or Asia handle those submissions outside the tool.

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

Unit21

On request
  • Unit21 Platform$undefined/year
    • Priced by monitored volume and modules, annual contract
    • Fraud, AML and case management packaged separately
    • Implementation and historical data backfill quoted with the subscription

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 Unit21 if

  • You need no-code rule builder.
  • You also want case management.
Unit21 review

Questions people ask

Is Restate or Unit21 better?
Neither clearly leads. Restate starts at Free and Unit21 at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Restate or Unit21?
Restate has a free tier; the other does not. Paid plans start at Free for Restate and On request for Unit21.
Does Restate or Unit21 run on more platforms?
Restate runs on Linux, macOS, Web. Unit21 runs on Web.
Can I use Restate for free?
Yes. Restate has a free tier, so you can try it without paying. Unit21 starts at On request.
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 Unit21 is typically brought in for.
What can Restate do that Unit21 cannot?
Restate covers Durable execution, Virtual objects, Single binary runtime, Multi-language SDKs. Unit21 covers No-code rule builder, Case management, SAR filing, Backtesting.

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.

Unit21: Do we need engineers to run it?

Only for the initial data integration. After that the design intent is that risk and compliance staff author and deploy rules themselves.

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.

Unit21: Does it file SARs?

Yes, it generates and electronically files suspicious activity reports to FinCEN. Non-US regimes are not covered to the same depth.

Restate: Is there a free tier?

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

Unit21: Can we test a rule before it goes live?

Yes. Backtesting against historical data to see projected alert volume is one of the more useful parts of the product, because alert volume is the real cost.

Restate: Which languages are supported?

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

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