Practice AWS networking.
Without the AWS bill.
An interactive simulator for Transit Gateway, Direct Connect, BGP, and VIFs. Build a topology, run a connectivity trace, and see exactly where the path breaks — and why.
The hard topics are the ones you can't afford to practice.
A technical audience trusts figures, not adjectives. So here are the figures.
The hardest AWS networking domains — TGW routing, Direct Connect, BGP path selection, VIFs, DXGW — are exactly the ones that are prohibitively expensive and often structurally impossible to build on real AWS as a solo learner.
Dedicated Direct Connect doesn't just cost money — it requires physical presence at an AWS DX colo facility. Most learners literally cannot build a multi-VIF DXGW + transit-VIF + BGP lab at any price. So they read diagrams and hope.
- Dedicated Direct Connect1 Gbps port$216 / mo
- Colo rack + cross-connectrequired for dedicated DX$500–2,000 / mo
- Transit Gatewaybase + per-attachment + per-GBmetered
- Site-to-Site VPN, NAT GWhourly + data processingmetered
- Public IPv4 + data transferwhile you fumble scenariosmetered
Three things, done well. Nothing else.
Not a course. Not a video library. A simulator that responds to the exact networking decisions real AWS makes.
Build a topology
Drop VPCs, gateways, VIFs, and on-prem peers onto a canvas — or paste a YAML topology and watch it render. Fourteen service primitives, real CIDR math, real ASNs.
Run a connectivity trace
Pick a source IP and destination IP. TransitLab evaluates route tables, propagation, allowed prefixes, and BGP best-path — hop by hop — the way AWS does.
See where it breaks — and why
When a trace fails you get the line: the missing prefix, the blackhole route, the propagated route that loses to a more-specific static. Not "check your config."
YAML in, topology out, trace running.
Your topology is text — source-controllable and diff-able, like terraform plan. The canvas is the rendering.
The expensive parts of AWS networking. Simulated.
The simulator implements the behavior, not a UI skin. Seventeen primitives and real route evaluation.
Nobody else simulates the routing.
Quiz banks
Tutorials DojoTest recall. Never hands-on.
Video courses
Cantrill · MaarekGreat teaching — but the labs run on your AWS bill.
API mocks
LocalStack · FlociFake the control plane so SDKs talk. No routing.
LocalStack mocks the AWS control plane. TransitLab models the data plane — the routing itself.
A different category. An interactive AWS networking simulator that didn't exist until now.
I've run networks for twenty years — and going deep on AWS's hybrid-networking stack still humbled me. Not the concepts, but that I couldn't afford to practice the topics that mattered on real AWS.
So I built the thing I needed: a simulator that models the routing faithfully enough to learn from, with none of the bill. This is it.
- $0 aws No AWS account, no idle charges. The whole thing runs in your browser — nothing to provision, nothing to tear down before the bill arrives.
- deterministic Same topology, same trace, same result — always. Route evaluation is a pure function, so you can diff what BGP did on Tuesday vs. today.
- break it Sandbox the failure modes you'd never trigger on real AWS. Drop a propagated route. Inject a more-specific static. Misconfigure allowed_prefixes. Watch the path break.
- portable YAML topologies, like Terraform. Share one in a PR or a study-group note; bisect a routing problem by version-controlling the network.
It's free.
TransitLab is a learning tool, and it's free to use — no paywall, no subscription, no AWS bill. Open it in your browser and start tracing.
- ✓ Free to use — no subscription, no per-hour metering, no credit card
- ✓ Every topic: TGW core, hybrid VPN + BGP, the full Direct Connect suite
- ✓ Runs in your browser — nothing to provision, nothing to tear down
Practice the hard parts.
Skip the bill.
It's free and runs in your browser — no signup, no aws configure required.
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