Please note: the serverless function features described in this article are specifically for developer projects. This includes both UI extensions and CMS React modules. For information about building serverless functions for websites outside of developer projects, visit the CMS documentation.

Fetching data with serverless functions (BETA)

APPLICABLE PRODUCTS
  • Sales Hub
    • Enterprise
  • Service Hub
    • Enterprise
  • Content Hub
    • Enterprise

When needing to fetch data for a project-based private app, whether for a UI extension or CMS React project, you'll use a serverless function. When executed, HubSpot runs the serverless function server-side using JavaScript. Because HubSpot runs the function, you don't need to manage your own server. 

Your access to using serverless functions depends on your HubSpot subscription:

  • UI extensions: using serverless functions for UI extensions requires a Sales Hub or Service Hub Enterprise subscription. You can also test out UI extensions for private apps for free in a developer test account. 
  • CMS: using serverless functions for CMS React projects requires a Content Hub Enterprise subscription.

Within the project file structure, serverless functions live in the src/app directory within a <AnyName>.functions folder. At the most basic level, this folder should include:

  • One or more JavaScript files that export a main function.
  • A serverless.json file that registers and configures your functions. Learn more about serverless function configuration.

example-project-serverless-structure-simple

Create a serverless function

Serverless functions for private apps in projects can be executed in two ways:

  • App function: a serverless function that gets executed directly from within the project. The function is made available to UI extension's React file through the runServerless argument.
  • Endpoint function (Content Hub Enterprise only): an app function that is invoked by calling a public URL. The URL is determined by the account's connected domains and the path specified in the serverless.json file. This is more common for implementing serverless functions in CMS React modules.
Please note: serverless functions cannot import other functions. You'll need to include all the code the serverless function needs to execute within the serverless function file. 

Configuration

In the serverless functions directory, configure the serverless function with a serverless.json file. In this file, you'll configure your serverless function name and the path of the JavaScript file to execute, along with any secrets that might need to be included for authentication. 

If you have a Content Hub Enterprise subscription, you can configure a serverless function to be invoked by a public URL by including an endpoint object in the config. Learn more about endpoint functions.

// Example serverless.json { "appFunctions": { "functionName": { "file": "function1.js", "secrets": ["SOME_SECRET"], "endpoint": { "path": "path/to/endpoint", "method": ["GET"] } } } }
Use this table to describe parameters / fields
ParameterTypeDescription
file
String

The .js file in the project to execute.

secrets
Array

To authenticate requests, you can include secrets as string values in this array. Learn more about managing secrets.

endpoint
Object

If invoking the function by a public URL (Content Hub Enterprise only), this object defines the endpoint details:

  • path: the endpoint path.
  • method: the request method.

Building the function

Each serverless function exports a main function that gets called when HubSpot executes it. The function receives the context argument, which is an object that contains data based on how the function is being used. This includes context about where the card is loaded as well as the authenticated user and account. Learn more about what's included in the context object.

Below is an example of a function that returns a 200 status code and a Hello World message:

//helloWorld.js exports.main = async (context) => { return ({ statusCode: 200, body: { message: 'Hello World' }, }); };

For a more complete example of an app function, HubSpot's boilerplate quickstart template includes the following function:

  • When invoked, the function returns a response containing static text along with variable text (which is entered into the extension's input field).
  • The serverless.json file specifies the name of the function, which is used in the extension's React file. It also specifies where the function file is located in the project.
  • The extension includes invokes the function on button click, providing a text value to the function if text is included in the input field. The React file below is based on the boilerplate quickstart template, but has been simplified to highlight the serverless function.
// example-function.js exports.main = async (context = {}) => { const { text } = context.parameters; const response = `This is coming from a serverless function! You entered: ${text}`; return response; }; { "appFunctions": { "myFunc": { "file": "example-function.js", "secrets": [] } } } import React, { useState } from "react"; import { Button, Flex, Input, hubspot } from "@hubspot/ui-extensions"; // Define the extension to be run within the Hubspot CRM hubspot.extend(({ context, runServerlessFunction, actions }) => ( <Extension context={context} runServerless={runServerlessFunction} sendAlert={actions.addAlert} /> )); // Define the Extension component, taking in runServerless, context, & sendAlert as props const Extension = ({ context, runServerless, sendAlert }) => { const [text, setText] = useState(""); // Call serverless function to execute with parameters. // The `myFunc` function name is configured inside `serverless.json` const handleClick = async () => { const { response } = await runServerless({ name: "myFunc", parameters: { text: text } }); sendAlert({ message: response }); }; return ( <Flex direction="row" align="end" gap="small"> <Input name="text" label="Send" onInput={(t) => setText(t)} /> <Button type="submit" onClick={handleClick}> Click me </Button> </Flex> ); };

Please note: serverless functions have a response limit of 15 seconds. Functions that take longer to execute will fail. 

Endpoint functions

If you have a Content Hub Enterprise subscription, you can configure a serverless function to be invoked by a public URL. When calling the URL of a HubSpot-hosted serverless function, you can use any domain connected to your account with the following URL structure: https://<domain>/hs/serverless/<endpoint-path-from-config>.

For example, if both website.com and subdomain.brand.com are connected to the account, you could call the function using https://website.com/hs/serverless/path/to/endpoint or https://subdomain.brand.com/hs/serverless/path/to/endpoint.

In the URL to call the function, the endpoint path is global rather than scoped to the app or project. If you have identical endpoint paths across multiple apps or projects, the most recently deployed endpoint function will take precedence. 

// Example serverless.json { "appFunctions": { "functionName": { "file": "somefunction.js", "secrets": ["SOME_SECRET"], "endpoint": { "path": "path/to/endpoint", "method": ["GET"] } } } }

Authenticate calls

When developing a private app with projects, each private app comes with a private access token that you can use to authenticate calls to HubSpot's APIs. You can also authenticate calls using secrets, which you'll manage through the CLI. To make your private app access token or secrets available for local development, you'll need to create a .env file in the .functions directory.

Pleas note: calls authenticated with private app access tokens count against your API call limits.

For example, if you wanted to use Node to make a request to a HubSpot API:

// Include HubSpot node API client const hubspot = require('@hubspot/api-client'); exports.main = async (context = {}) => { // Get hs_object_id of the record in context const { hs_object_id } = context.propertiesToSend; console.log(`Looking up contact by ID [${hs_object_id}]`); // Instantiate HubSpot Node API client const hubspotClient = new hubspot.Client({ accessToken: process.env["PRIVATE_APP_ACCESS_TOKEN"] }); // Your function }

You can then configure the rest of the function using Node.js. For example, the following code would create a serverless function that retrieves the current contact by ID using the contacts API:

// Include HubSpot node API client const hubspot = require('@hubspot/api-client'); exports.main = async (context = {}) => { // Get hs_object_id of the record in context const { hs_object_id } = context.propertiesToSend; console.log(`Looking up contact by ID [${hs_object_id}]`); // instantiate HubSpot Node API client const hubspotClient = new hubspot.Client({ accessToken: process.env["PRIVATE_APP_ACCESS_TOKEN"] }); const properties = [ "firstname", "lastname" ]; try { const apiResponse = await hubspotClient.crm.contacts.basicApi.getById(hs_object_id, properties); console.log(JSON.stringify(apiResponse)); } catch (e) { e.message === 'HTTP request failed' ? console.error(JSON.stringify(e.response, null, 2)) : console.error(e) } }

To get started, you can find Node.js code snippets on the Endpoints tabs of HubSpot's API docs.

Managing secrets

If your serverless function requires secrets, include a secrets field in the serverless.json configuration file. Follow the steps below to make them accessible when the function is deployed and when running the local development server.

  • Create your secrets by running hs secrets add <secret name>. HubSpot will securely store this secret on its backend and inject them into the runtime environment when a function is invoked in production.
  • In your serverless.json file, list the names of the secrets needed by each function. Do not include PRIVATE_APP_ACCESS_TOKEN in this array, as this is automatically created for you and already available in the serverless function.
// serverless.json { "appFunctions": { "functionName": { "file": "function1.js", "secrets": ["GITHUB_ACCESS_TOKEN"] } } }
  • To make secrets available for local development, create a .env file in the <AnyName>.functions directory. HubSpot will never retrieve your secrets outside of its protected infrastructure, so you'll need to specify the secret values that you want to use when the function is executed locally. If your function uses PRIVATE_APP_ACCESS_TOKEN, you'll need to copy the private app's access token from HubSpot and store it in the .env file for local access. The following snippet demonstrates what an example .env file might look like:
PRIVATE_APP_ACCESS_TOKEN=pat-na1-****** ANOTHER_SECRET=my-secret-value
  • After saving secrets to the .env file, you can access them in your function using process.env["<keyName>"].
export const main = async (context) => { const secret = process.env["ANOTHER_SECRET"]; const token = process.env["PRIVATE_APP_ACCESS_TOKEN"]; ... }
  • To update a secret's value, you can run the hs secrets update command. If you're using a Node runtime of 14 or higher, updated secret values will  automatically be updated in your deployed function within one minute, meaning you won't have to build and deploy to get the updated secret.

Please note: 

  • To limit exposure of a secret, it's strongly recommended to never include it in console statements to prevent it from being recorded in logs.
  • If your project is linked to a GitHub repository, be sure to never commit the .env file when uploading to GitHub. You can include an entry for .env in your .gitignore file to ensure that it is omitted from your commits.

Best practices

Keep the following recommendations in mind while you develop and test your serverless function:

Variable assignment inside functions

To ensure that variables are correctly assigned and initialized with every function invocation, you should opt to assign variables within the function itself. This practice prevents potential issues related to stale or persistent variable states, which can lead to unexpected behaviors. See the example below for additional context:

// Preferred exports.myHandler = async (event, context) => { const myDynamicVariable = process.env['SOME_KEY']; // The rest of your handler logic }; // Discouraged const myDynamicVariable = process.env['SOME_KEY']; exports.myHandler = async (event, context) => { // The rest of your handler logic };

Stay up to date with the latest platform version

The hsprojects.json configuration file includes a platformVersion field which specifies which platform version to run the project on. It's strongly encouraged to use the latest platform version to ensure that your project and its assets are up to date with the latest improvements, optimizations, and feature enhancements. In addition, some previously available features may not be available in older versions due to deprecation.

The platform version also dictates which version of Node the project runs on. The latest version, 2023.2, uses Node18, and doesn't support older versions of Node.

Including dependencies

By default, HubSpot provides a small number of NPM dependencies in addition to the Node.js standard library. To add your own dependencies, you can list the package in dependencies within the package.json file. When the app is built, dependencies will be bundled with your function code. All dependencies must be published to NPM and be public.

For example, if you wanted to add the lodash library in a serverless function, you would first update package.json to include the dependency:

// package.json { "name": "app.functions", "version": "1.0.0", "description": "", "dependencies": { "lodash": "^4.17.21", } }

Then, at the top of your serverless function JavaScript file, you would require the lodash dependency:

// myFunction.js const _ = require('lodash'); exports.main = async (context) => { const objectA = {}; const objectB = {}; const equal = _.isEqual(objectA, objectB); return ({ statusCode: 200, body: { isEqual: equal, }, }); };

Debug a serverless function

Log messages are produced every time HubSpot executes a serverless function. Below, learn how to access logs in HubSpot and locally using the CLI.

In-app debugging

In HubSpot, you can view a serverless function's log history for both app functions and endpoint functions, including successful requests and errors.

To access a serverless function's logs in HubSpot:

  • In your HubSpot account, navigate to CRM Development.
  • In the left sidebar menu, navigate to Private apps.
  • Select the private app that contains the serverless function.
  • Click the Logs tab.
  • To view logs for a serverless app function, click the Serverless functions tab. To view logs for a serverless endpoint function, click the Endpoint functions tab.
  • In each tab, you can view logs for specific requests by clicking the request. You can also use the search bar to search by request ID.
  • In the right panel, you can then click View log trace for a more in-depth breakdown of the request.

view-serverless-app-function-logs

You can also include console.log() in your serverless function code for debugging purposes, then view its output in the function log details sidebar.

Local debugging

Log messages are produced every time HubSpot executes a serverless function. To view a serverless function's logs in the CLI, run the hs project logs command. Learn more about using the hs project logs command.

There are two types of log messages produced:

  • Log messages that record the execution of a function, along with its status and timing. For example: 2021-04-28T19:19:21.666Z - SUCCESS - Execution Time: 279ms
  • Log messages that are produced through console statements in the function code. For example, your serverless function JavaScript might include:
// helloWorld.js exports.main = async (context) => { console.log('Log some debug info'); console.error('An error occurred'); return ({ statusCode: 200, body: { message: 'Hello World' }, }); };

A log output for the above code would then produce the following:

2021-04-28T19:15:13.200Z    INFO   Log some debug info

2021-04-28T19:15:14.200Z    ERROR    An error occurred

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