Custom Ninja Forms + Hubspot integration.

class-nf-hubspot.php

<?php
/**
 * Hubspot Integration for Ninja Forms.
 *
 * @package Nano
 */
class NF_Hubspot {

	// Hooks into ninja_forms_after_submission
	public function init() {

		// Define your API key in wp-config.php as a constant
		if ( defined( "HAPI_KEY" ) ) {
			add_action( 'ninja_forms_after_submission', array( $this, 'process_form_data' ) );
		}

	}

	// Process the Ninja Forms data we want for Hubspot
	public static function process_form_data( $form_data ) {

		// Ninja Form data
		$form_id = $form_data['form_id'];
		$fields = $form_data['fields'];

		// Hubspot data only processed for form_id(s) 1 & 2
		if ( ! in_array( $form_id, array( "1", "2" ) ) ) {
			return;
		}

		// Fields for Hubspot
		$first_name = '';
		$last_name = '';
		$email = '';

		// Contact form
		if ( "1" === $form_id) {
			$name = $fields[1]['value'];
			$email = $fields[2]['value'];
		}

		// Nanofesto form
		if ( "2" === $form_id) {
			$name = $fields[5]['value'];
			$email = $fields[6]['value'];
		}

		// Our Ninja Forms field does not have first_name & last_name
		// So this attempts to split the single "name" field
		$name = self::split_name( $name );

		// Form Data to Post
		$data['properties'][] = array( "property" => "email", "value" => $email );
		$data['properties'][] = array( "property" => "firstname", "value" => $name[0] );
		$data['properties'][] = array( "property" => "lastname", "value" => $name[1] );

		self::post_data_to_hubspot( $data );

	}

	// Splits the name field into first_name and last_name
	// https://stackoverflow.com/questions/13637145/split-text-string-into-first-and-last-name-in-php
	public static function split_name( $name ) {
		$name = trim( $name );
		$last_name = ( strpos($name, ' ') === false) ? '' : preg_replace('#.*\s([\w-]*)$#', '$1', $name );
		$first_name = trim( preg_replace('#'.$last_name.'#', '', $name ) );
		return array( $first_name, $last_name );
	}

	// Posts our data to Hubspot
	public static function post_data_to_hubspot( $data ) {

		$args = array(
			'headers'   => array(
				'Content-Type' => 'application/json'
			),
			'body' => json_encode( $data )
		);

		$api_url = 'https://api.hubapi.com/contacts/v1/contact?hapikey=' . HAPI_KEY;
		$response = wp_remote_post( $api_url, $args );

		// Log $response if $error
		if ( is_wp_error( $response ) ) {
			error_log( $response->get_error_message() );
		}

	}

}

$hubspot = new NF_Hubspot();
$hubspot->init();