Loopback Cloud runs AWS, Azure, and GCP on your machine so agents — and the people
building them — provision and stress real resources over MCP with zero spend and zero blast
radius. The same SDKs, CLIs, and IaC you already use, behind one unified console with a gated
multicloud interconnect. No account, no auth token, no feature gates. Just docker compose up.
# one stack — AWS, Azure & GCP on localhost $ docker compose up ✓ AWS ready on :4566 ✓ Azure ready on :4577 ✓ GCP ready on :4588 $ aws s3 mb s3://demo # AWS $ az storage container create # Azure $ gcloud storage buckets create # GCP $ claude mcp add loopback :4566/_loopback/mcp ✓ agent connected — 42 tools, zero blast radius
Everything you — or your AI agent — need to build, test, and demo cloud apps. Local, fast, and free.
Browse AWS, Azure, and GCP resources side by side in a single read-only UI. Flip between providers without leaving the page.
Point the AWS, Azure, and GCP SDKs, CLIs, Terraform, CDK, and OpenTofu at localhost. Keep your code — just change the endpoint.
A GraalVM native image with a ~24 ms cold start and ~13 MiB idle footprint. Fast enough to spin up fresh in every test.
Model cross-cloud connectivity like AWS Interconnect — gated by default, opened with one attachment from the hub to a peer cloud.
No account, no telemetry, no outbound calls. Works in air-gapped CI and on a plane. Fake credentials are fine — any non-empty value.
Ship the live stack to your team: HTTPS via Let's Encrypt, the console behind auth, all from one Docker Compose file.
Loopback Cloud models AWS Interconnect — multicloud as a hub-and-spoke. The AWS hub owns the control plane; Azure and GCP each run an interconnect gateway.
403 until a link exists — and chaos rules can sever or slow a live link.azure or gcp./_loopback/interconnects/authorize and the same call now returns 200.Built-in control planes that turn all three clouds into a lab — drive them from an AI agent over MCP, the console, or a tiny /_loopback/* API. Each is inert until you switch it on.
A built-in Model Context Protocol server lets AI agents build real infra (buckets, queues, parameters), inspect every cloud, and drive every lab — zero spend, zero blast radius.
Bedrock Converse / ConverseStream / InvokeModel / InvokeModelWithResponseStream, Azure OpenAI, and Vertex AI — one offline gateway (deterministic, canned, or Ollama) with token-cost simulation. Grok 4.6 on Bedrock (xai.grok-4.6) and Vertex (grok-4.6 / publishers/xai). Azure has no official Grok.
Inject latency and native-shaped errors into any service, in any of the three clouds — and sever or slow cross-cloud links — to test retries, timeouts, and failover.
A virtual clock in every cloud. Fast-forward and tokens expire, TTL'd items vanish, schedules fire, hidden queue messages reappear — or freeze time for deterministic tests.
A live per-service cost meter and what-if projector — wired to the clock, so you can watch a month of spend accrue in seconds.
Export the entire emulator's state to one file and restore it anywhere — git for cloud state. And ask IAM exactly which policy statement denied a call.
$ curl -s localhost:4566/_loopback/chaos -H 'Content-Type: application/json' \ -d '{"service":"dynamodb","errorCode":"ThrottlingException","probability":0.5}' $ aws dynamodb list-tables An error occurred (ThrottlingException): Chaos fault injected # retries, backoff, and circuit breakers — finally testable. Clear with one DELETE.
$ curl -s -X POST localhost:4566/_loopback/clock/advance \ -H 'Content-Type: application/json' -d '{"days":30}' {"instant":"…+30 days","mode":"offset"} # 30 days later: STS tokens expired, DynamoDB TTLs swept, schedules fired — # and on Azure, hidden queue messages are visible again.
$ curl -s localhost:4566/_loopback/costs {"runRate":{"perHour":0.0104,"perMonth":7.59},"monthToDate":2.31,"byService":[…]} $ curl -s 'localhost:4566/_loopback/costs/whatif?scale=10&months=6' {"baselinePerMonth":7.59,"projectedPerMonth":75.92,"projectedTotal":455.52} # freeze the clock at month-end and the meter shows a full month of spend
# Bedrock — ConverseStream / InvokeModelWithResponseStream (EventStream, not 501) $ curl -s localhost:4566/model/anthropic.claude/converse-stream -d '{"messages":[…]}' # Grok 4.6 on Bedrock (xai.grok-4.6) — no official Grok on Azure OpenAI $ curl -s localhost:4566/model/xai.grok-4.6/converse -d '{"messages":[…]}' # Azure OpenAI — add "stream":true for SSE chunks $ curl -s localhost:4577/openai/deployments/gpt-4o/chat/completions -d '{"messages":[…]}' # Vertex — publishers/xai grok-4.6, or Gemini streamGenerateContent $ curl -s localhost:4588/v1/projects/p/locations/us/publishers/xai/models/grok-4.6:generateContent # one offline gateway behind all three — deterministic in CI, or a real local Ollama model
$ curl -s localhost:4566/_loopback/mcp -H 'Content-Type: application/json' -d '{ "jsonrpc":"2.0","id":1,"method":"tools/call", "params":{"name":"create_bucket","arguments":{"name":"agent-made"}}}' {"result":{"structuredContent":{"bucket":"agent-made","created":true}}} # 42 AWS / 24 Azure / 19 GCP tools: inspect, provision, chaos, clock, GenAI
$ curl -s localhost:4566/_loopback/state/export > snapshot.json # … run a destructive test, break everything … $ curl -s localhost:4566/_loopback/state/import --data-binary @snapshot.json {"restoredEntries":128,"skippedStores":0} # every service, every account — back exactly as it was
Start AWS, Azure, and GCP locally with a single command.
docker compose up
Use the SDKs and CLIs you already have. Credentials can be anything.
export AWS_ENDPOINT_URL=
http://localhost:4566
Confirm what got created and copy IDs, ARNs, and endpoints.
/_loopback/console → pick a cloud
Point any MCP client at the built-in server. It can build, break, and bill — all locally.
claude mcp add loopback
:4566/_loopback/mcp
Loopback Cloud Console
localhost:4566/_loopback/console
61 AWS · 30 Azure · 26 GCP. Real Docker-backed engines where fidelity matters, fast in-process emulation everywhere else — including DynamoDB SearchVectors and an AI suite in every cloud.
= real Docker-backed engine · everything else runs in-process
LocalStack's community edition sunset in March 2026 — auth tokens required, security updates frozen. Loopback Cloud stays free, fast, and open.
| Capability | Loopback Cloud | LocalStack Community |
|---|---|---|
| Auth token required | No | Yes |
| Security updates | Active | Frozen |
| Cold start | ~24 ms | ~3.3 s |
| Idle memory | ~13 MiB | ~143 MiB |
| Azure + GCP emulation | Yes | No |
| Chaos · time travel · cost lab · snapshots | Yes | No |
| MCP server + GenAI gateway | Yes | No |
| License | MIT | Restricted |
Drop-in friendly: point AWS_ENDPOINT_URL at localhost:4566 and keep your SDKs, CLIs, and IaC.
One Compose file brings up all three emulators behind a reverse proxy with automatic HTTPS. Share a single, always-on sandbox for demos, integration tests, and onboarding — on your own infrastructure.
/, console at /consoleAWS, Azure, and GCP on your machine in seconds — no account, no auth token, no spend. A cloud your agent can break without breaking anything.