asynkr
Right now, testing an event chain means five browser tabs and a shell history full of AWS CLI commands.
The basics, done right
All your events in one place
Save the payloads you test constantly and reuse them any time — instead of rebuilding them from scratch or digging through the AWS console for what you sent last week.
JSONata templating
Build dynamic payloads with real expressions, not copy-pasting.
Faker.js built in
Generate realistic fake data on the fly instead of hardcoding the same three test users.
Multi-account & SSO
Switch between AWS profiles and SSO sessions without re-authenticating every time.
Runs locally
A native app: every AWS call goes straight from your machine to AWS. Credentials and payloads never touch our servers.
One window, not ten tabs
No more switching between browsers and consoles just to send one test event.
Point a payload at a real target and see exactly where it went.
Pick an EventBridge bus, Lambda function, SQS queue, SNS topic, or Step Functions state machine as the destination, preview the resolved payload, and check the result tab to confirm what actually got sent — no console tab required.
Write $faker.person.firstName(), not "John Doe" for the hundredth time.
Drop JSONata expressions straight into your payload and preview the resolved output before you send — UUIDs, timestamps, and realistic fake data generated on the fly, no copy-pasting from a spreadsheet.
Know which EventBridge rules will fire before you send.
Select a bus and the Event Rules tab lists its rules and shows, live as you edit, which ones your event would match. Open a rule to see every condition pass or fail, and where it sends events next.
See what AWS actually did with it, down to the Lambda logs.
Every send shows the raw AWS response — or the error — right next to the payload you sent. For Lambda targets, pull up the matching CloudWatch logs without leaving the app.
Find your dead letters and see what's in them.
Asynkr spots your dead-letter queues and their source queues, then loads a sample of messages locally. Filter them with a JSONata expression or hand-pick the ones you care about.
Fix the payload, then send it back, anywhere.
Reshape every message with a JSONata transform and check the before and after on your own messages before anything moves. Then redrive them to any target. Not just back to the source queue.
Common questions
Is Asynkr free?
Yes — free during the beta. There's no pricing tier yet; right now we're focused on feedback from engineers who deal with this daily, not monetizing early.
What AWS permissions does it need?
Only what your own AWS profile or SSO session already grants. Asynkr doesn't request any special access — it just calls the services you target using your existing credentials, so that profile needs permissions on whatever you point it at (e.g. events:PutEvents on an EventBridge bus, sqs:SendMessage on a queue, lambda:InvokeFunction on a function).
Does my data ever leave my machine?
No. Asynkr is a native app — SSO authentication and every AWS call happen locally, straight from your machine to AWS. Your credentials and payloads never pass through our servers.
Which AWS services are supported?
EventBridge, SQS, Lambda, SNS, and Step Functions as targets, plus EventBridge rule inspection and SQS dead-letter queue management. More on the way.
How accurate is the rule matching?
Asynkr evaluates event patterns locally with its own implementation of EventBridge matching, covering all documented operators and tested against AWS's TestEventPattern API. It's a very good preview, but AWS remains the source of truth.
Can I use multiple AWS accounts or SSO profiles?
Yes — switch between AWS profiles and SSO sessions without re-authenticating each time.
Free during beta.
No pricing tiers yet — just feedback from engineers who deal with this daily.
