Test Amazon Bedrock without touching a real API
Thrubit intercepts every Bedrock call in your state machines and Lambda functions — returning instant, shaped mock responses.
ZERO API costs. Zero latency. Zero surprises.
Every Bedrock iteration shouldn't cost money and take 30 seconds
Before Thrubit, every change to an AI-powered state machine meant a real model call — paying token costs, waiting for inference, and fighting throttle limits just to test your routing logic.
Pay per token. Wait per call.
Every test run hits the real Bedrock API — billing tokens, waiting 3–20 seconds for inference, risking throttle limits, and requiring valid AWS credentials just to verify your state machine routing and Lambda handler logic.
Mock once. Run instantly. Pay nothing.
Flip the Bedrock mock toggle in Settings. Every invokeModel, converse, and retrieve call returns an instant, correctly-shaped response in under 200ms — so you can focus on your workflow logic, not your AWS bill.
Switch between real and mock Bedrock in seconds
The Bedrock mock is a global setting in Thrubit's AWS panel. Turn it on and every Bedrock call — whether it originates from a Step Functions native integration or from inside a Lambda function — is intercepted and returns a mock response immediately. No code changes. No environment variables.
- Works for both Step Functions native Bedrock integrations (
arn:aws:states:::bedrock:invokeModel) and direct SDK calls inside Lambda - The same toggle covers all Bedrock APIs in the same execution
- Switch back to real AWS at any time — no restart required
- Mock state is shown inline alongside each state node's log output
"modelId":
"claude-3-5-sonnet-20241022",
"body": {
"messages": [...]
}
}
"output": {
"message": {
"role": "assistant",
"content": [{
"text": "[Mock]..."
}]
}},
"stopReason": "end_turn"
}
Mock responses that match the real Bedrock schema
Thrubit doesn't return a generic placeholder. Each mock response is shaped to match exactly what the real API returns for that model family — so your ResultSelector mappings, Lambda parsing code, and downstream state transitions all work exactly as they will in production.
- Claude 3 / Nova responses include
output.message.content[].textandstopReason - Titan Text returns
results[].outputTextwith token counts - Knowledge Base
retrieveAndGeneratereturns fullcitationsandoutput.textstructure - Guardrail
applyGuardrailreturnsaction: "NONE"and coverage object - Stable Diffusion / Titan Image returns a valid 1×1 base64-encoded PNG artifact
Mocks wherever Bedrock is called — state machine or Lambda
Bedrock appears in two places in modern Step Functions architectures: as a native service integration in the ASL, and as a direct SDK call inside a Lambda function. Thrubit intercepts both.
- ASL-level
arn:aws:states:::bedrock:invokeModeltask states are intercepted by the execution engine - Lambda-side calls via
AWS.BedrockRuntime.invokeModel()are patched at the SDK prototype level before your handler runs - The same shaped responses are returned in both paths — your
ResultSelectorand handler parsing code both work correctly - No changes to your Lambda code required — the mock is injected transparently into the isolated process
ASL Native Integrations
bedrock:invokeModelbedrock:conversebedrock-agent-runtime:retrievebedrock-agent-runtime:retrieveAndGeneratebedrock:applyGuardrailbedrock-agent:invokeAgent
Direct SDK Calls
BedrockRuntime.invokeModel()BedrockRuntime.converse()BedrockRuntime.retrieveAndGenerate()BedrockRuntime.retrieve()BedrockRuntime.applyGuardrail()BedrockRuntime.invokeAgent()
Every major Bedrock model family, mocked correctly
Thrubit detects the model ID and returns a response shaped to that family's schema — so your parsing code and selectors work without touching the real API.
output.message.content[].text with stopReason: "end_turn" and usage tokens. Legacy Claude 2 returns completion field.output.message structure with stopReason and usage object matching production format.results[].outputText with tokenCount and completionReason: "FINISH" matched to the Titan Text schema.generation, prompt_token_count, generation_token_count, and stop_reason: "stop" per the Llama bedrock schema.outputs[].text with stop_reason field shaped to the Mistral Bedrock response format.generations[].text with likelihood and finish_reason: "COMPLETE" per the Cohere Command schema.artifacts[].base64 with finishReason: "SUCCESS" — parses correctly downstream.citations array, output.text, and sessionId for RAG flows. Agent responses include completion and sessionState.Up and running in under a minute
No code changes, no environment variables, no AWS credentials required to use mock mode.
In Thrubit, open the Settings panel and navigate to the AWS tab. You'll see the Bedrock and SQS mock toggles alongside your AWS profile and region configuration.
Flip the Bedrock toggle from "Real AWS" to "Mock". The change takes effect immediately — no restart needed. Run your state machine or invoke your Lambda just as you normally would.
Every Bedrock call returns an instant mock response shaped to the correct model schema. Build your routing logic, test error handling, and validate your ResultSelector — all at zero API cost.
When you're ready to validate against the real model, toggle back to "Real AWS" and run again. Because your parsing code was working against the correctly-shaped mock, it works against the real API too.
Stop burning tokens to test your workflow logic.
Download Thrubit and run your first Bedrock-powered state machine locally in under five minutes — at zero cost, with full mock responses for every model family.
What teams are saying
Real feedback from engineers, trainers and decision makers.
“Thrubit cut our Step Functions debugging cycle from 15 minutes per iteration down to seconds. The visual trace is worth the price alone. It’s become an essential part of our development workflow.”
“I was looking for ways to make Step Functions and Lambdas more tangible for students. Thrubit makes it significantly easier to visualize workflows and experiment locally, accelerating real understanding.”
“Thrubit saves us over $24k a year & protects us from surprise AWS bills. One rogue state machine once cost us 10x our typical month. With Thrubit, that risk is gone and our developers iterate faster.”
