Hosted functions

Hosted functions are project-scoped TypeScript handlers hosted by Wabery. Use them when a WhatsApp workflow needs server-side logic close to the conversation: quote calculators, order lookups, enrichment, routing decisions, or small tools that a Business Agent can call.

Functions are created as metadata first, then deployed from source. A function must be active and have a successful deployment before Wabery can invoke it.

Note

New to Wabery? Complete the Quickstart first. Hosted functions assume you already have a project, an API key or CLI login, and a test conversation or workflow that needs server-side logic.

Create and deploy

CLI

wabery functions create \
  --slug quote-customer \
  --name "Quote customer" \
  --trigger-type ANY_MESSAGE

wabery functions deploy fn_... --source ./quote-customer.ts
wabery functions test fn_... --text "Can you quote this?"
wabery functions logs fn_...

SDK

const fn = await wabery.functions.create({
  slug: "quote-customer",
  name: "Quote customer",
  triggerType: "ANY_MESSAGE",
});

await wabery.functions.deploy(fn.id, {
  source: `
export default async function handler(event, ctx) {
  ctx.log("received", event.type);
  return { reply: "Thanks, we will follow up." };
}
`,
});

await wabery.functions.test(fn.id, { text: "Can you quote this?" });

curl

curl https://api.wabery.com/v1/functions \
  -H "Authorization: Bearer $WABERY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "quote-customer",
    "name": "Quote customer",
    "trigger_type": "ANY_MESSAGE"
  }'

curl https://api.wabery.com/v1/functions/fn_.../deploy \
  -H "Authorization: Bearer $WABERY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"source":"export default async function handler(event, ctx) { return { ok: true }; }"}'

trigger_type matches automation triggers: KEYWORD, WELCOME, or ANY_MESSAGE.

Function source

Export a default async handler. Wabery passes the normalized event and a scoped context object.

export default async function handler(event, ctx) {
  const profile = await ctx.data.get("profile");
  await ctx.kv.put("last_event", event.type);
  ctx.log("message", event.text);

  return {
    ok: true,
    profile,
  };
}

Context access is scoped to the authenticated project and contact. Functions are request/response handlers; keep them bounded and use logs for debugging rather than long-running work.

Expose as a tool

Hosted functions can back a Meta Business Agent connector tool, or be exposed as an external MCP/tool call. External invocation is opt-in:

wabery functions update fn_... \
  --expose-as-mcp-tool true \
  --input-schema '{"type":"object","properties":{"orderId":{"type":"string"}}}'

wabery functions invoke fn_... --arguments '{"orderId":"ord_123"}'

SDK equivalent:

await wabery.functions.update("fn_...", {
  exposeAsMcpTool: true,
  inputSchema: {
    type: "object",
    properties: { orderId: { type: "string" } },
  },
});

await wabery.functions.invoke("fn_...", {
  arguments: { orderId: "ord_123" },
});

To wire a Business Agent tool to hosted logic, create a connector tool with backing_type: "HOSTED_FUNCTION" and backing_function_id: "fn_...".

API scopes

Use scoped API keys where possible:

Scope	Allows
functions:read	List functions, fetch source, read invocation logs.
functions:write	Create, update, deploy, test, and delete functions.
functions:invoke	Invoke an exposed function as a tool.

The CLI and MCP server use the same REST endpoints. MCP write tools require write mode and confirmation tokens for create, deploy, update, invoke, and delete actions.