Wormhole has deployed Core Bridge, Token Bridge and NFT Bridge contracts on various testnets of the chains connected by Wormhole. You can see the deployed addresses [here](./contracts.md).
Tilt is a Kubernetes-based tool that runs a copy of every chain along side a Guardian node to create a simulated testing environment. Details on how to set it up and test against it is [here](../development/tilt/overview.md).
The SDK is a set of Javascript tools to help you do Token Bridge transfers, plus fetch and submit VAAs from one chain to another. You can install it via [NPM](https://www.npmjs.com/package/@certusone/wormhole-sdk).