Getting started

This page creates and verifies a first project. The normal application journey continues through init → doctor → test → dev → build; see Project lifecycle for the canonical sequence and the optional inspect and advanced compile branches.

Requirements

• Node.js 22.14.0 or newer on the 22.x line, or Node.js 24.x (^22.14.0 || ^24.0.0).
• npm 10 or another npm-compatible package manager.
• A repository checkout with its lockfile-pinned dependencies restored, using pnpm pulse -- <command>, or the synchronized public package set produced by release acceptance.
• A Fastly local execution engine only when running the external Fastly Compute reality workflow. Native compilation and configured-provider builds do not require one. The gate accepts the Fastly CLI through PATH/PULSE_FASTLY_BIN or direct Viceroy through PULSE_VICEROY_BIN.

Create a project

The command and documented result below are executed by the documentation test lane.

pnpm pulse -- init ./hello-pulse --json

{
  "status": "initialized",
  "files": [
    ".gitignore",
    ".pulse/.gitignore",
    ".pulse/config.ts",
    "README.md",
    "package.json",
    "src/index.ts",
    "tests/pulse.harness.ts",
    "tsconfig.json"
  ]
}

Then enter the project and install the exact dependencies written by pulse init:

cd ./hello-pulse
npm install

pulse init never runs a package manager or performs hidden network work.

The generated project uses the conventional .pulse/config.ts workspace, an async Pulse application root from @pulse-compute/pulse, and a dedicated tests/pulse.harness.ts case module. The .pulse/.gitignore keeps generated workspace artifacts out of version control while retaining the project config.

Verify the project

npm run doctor
npm test

• doctor validates configuration, entry resolution, schema declarations, provider support, output safety, and required toolchains.
• test executes the configured cases through the selected provider’s local runtime.

Use npm run inspect when you need the capabilities, effects, continuations, schemas, target-support decision, or provider lowering required by the handler. It is observability, not a required lifecycle stage.

Run locally

npm run dev

pulse dev is a foreground server. It watches the handler and schema dependency graph, recompiles on change, and exits when the process receives a normal termination signal. It does not create a daemon or background worker. The executable docs lane starts it with --once, sends a real request, verifies the response, and checks clean shutdown.

Advanced: compile portable Pulse Wasm

npm run compile

pulse compile lowers the canonical handler into a deterministic provider-neutral execution plan and writes compact Pulse-owned WebAssembly. The output includes pulse-compile.json, canonical-native-plan.json, generated AssemblyScript, Wasm, WAT, and the native ABI manifest. It does not package a deployment provider or embed the Fastly JavaScript runtime.

The provider selected by the active .pulse/config.ts profile remains relevant to test, dev, and build, but it does not change the portable artifact produced by compile. Normal projects can proceed directly from dev to build; compile is not a prerequisite.

Build

npm run build

For Node, the build emits the canonical handler, program metadata, schema registry/codecs when configured, and pulse-build.json.

For Fastly, pulse build reads the provider and bindings from the selected .pulse/config.ts profile, compiles the same provider-neutral native plan, and emits generated Fastly-targeted AssemblyScript plus compact direct-host-ABI WebAssembly at bin/main.wasm:

npm run build

The public CLI does not accept provider overrides. Use pulse compile when only the portable pulse_host module is needed; use pulse build when the configured deployment realization is needed. Native builds always preserve generated source and Wasm together.

Provider-neutral compilation and Native provider builds may opt into the explicitly experimental size optimizer:

pulse compile --experimental-native-size
pulse build --experimental-native-size

The Native compiler resolves that intent to its experimental size profile. The current runtime and export surface remain unchanged, the default build is unaffected, and portable and provider manifests record the resolved profile. JavaScript build targets reject the flag.

For candidate-specific output and proof boundaries, continue with Node build and execution or Fastly deployment candidates.

Diagnose failures

Run pulse doctor --json and use the stable diagnostic code. See Troubleshooting and the diagnostics reference.

Next steps

• Start with examples/01-hello-json.
• Add upstream data with fetching and composition.
• Add bounded validation with explicit JSON schemas.
• Map platform data using Fastly capabilities.
• Check source eligibility in Managed handler TypeScript and JavaScript, then confirm the selected mode in Provider and target compatibility.