Substrate is a powerful SDK for building with AI, with batteries included: language models, image generation, built-in vector storage, sandboxed code execution, and more. To use Substrate, you simply connect tasks, and then run the workflow. With this simple approach, we can create AI systems (from RAG, to agents, to multi-modal generative experiences) by simply describing the computation, with zero additional abstractions.
Substrate is also a workflow execution and inference engine, optimized for running compound AI workloads. Wiring together multiple inference APIs is inherently slow – whether you do it yourself, or use a framework like LangChain. Substrate lets you ditch the framework, write less code, and run compound AI fast.
If you're just getting started, head to docs.substrate.run.
For a detailed API reference covering the nodes available on Substrate, see substrate.run/nodes.
npm install substrateimport { Substrate, ComputeText, sb } from "substrate";Initialize the Substrate client.
const substrate = new Substrate({ apiKey: SUBSTRATE_API_KEY });Generate a story using the ComputeText node.
const story = new ComputeText({ prompt: "tell me a story" });Summarize the output of the story node using another ComputeText node. Because story has not yet been run, we use sb.interpolate to work with its future output.
const summary = new ComputeText({
prompt: sb.interpolate`summarize this story in one sentence: ${story.future.text}`,
});Run the graph chaining story → summary by passing the terminal node to substrate.run.
const response = await substrate.run(summary);Get the output of the summary node by passing it to response.get.
const summaryOut = response.get(summary);
console.log(summaryOut.text);
// Princess Lily, a kind-hearted young princess, discovers a book of spells and uses it to grant her family and kingdom happiness.We're always creating new JS examples on val.town.
Many examples are also included in the examples directory.