In Nango, integration use-cases are mapped to syncs and actions. Before starting, determine if a sync, an action, or a combination of both fits your use case.
Pre-requisite: set up an integrations folder (step-by-step guide).

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Edit the nango.yaml configuration

In your nango-integrations folder, open the nango.yaml configuration file (reference).

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Configure a sync

This example nango.yaml configuration describes a sync that continuously fetches contacts from Salesforce:
nango.yaml
integrations:
    salesforce: # Integration ID
        syncs:
            salesforce-contacts: # Sync name (must match script name)
                description: |
                    Syncs contacts based on a field mapping object.
                runs: every day # Sync frequency
                output: Contact # Output model
                endpoint: /crm/contact # Unified Nango endpoint (always GET for syncs)
                scopes: offline_access,api # Necessary scopes

models:
    Contact: # Data model reference above
        id: string # Required unique ID
        first_name: string
        last_name: string
        email: string
        account_id: string
        last_modified_date: string
Learn more about sync configurations in the reference and check out example templates.

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Configure an action

This example nango.yaml configuration describes an action that synchronously fetches a contact by ID from Salesforce:
nango.yaml
integrations:
    salesforce: # Integration ID
        actions:
            salesforce-contact-fields: # Action name (must match script name)
                description: Fetch available contact fields
                output: ContactSchema # Output model
                endpoint: /crm/contact-field # Unified Nango endpoint (defaults to GET for actions)
                scopes: offline_access,api # Necessary scopes

models:
    ContactSchema:
        fields: string[]
Learn more about actions configurations in the reference and check out example templates.

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Write an integration script

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Generate the integration script scaffolding

Everytime that you modify the nango.yaml configuration, run: 
nango generate # (in `./nango-integrations`)
Among other things, this will generate the script files with initial scaffolding for any sync or action that you added (existing script files stay untouched).

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Start script development mode

Before you plan to modify your scripts, run: 
nango dev # Keep the tab open
This command starts a process that continuously compiles your integration scripts and prints code syntax errors.

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Write a sync script

Open the generated sync script (named [sync-name].ts) which should contain the following scaffolding :
salesforce-contacts.ts
import { NangoSync, Contact } from './models';

export default async function fetchData(nango: NangoSync): Promise<void> {
	// Integration code goes here.
}
Fill in the fetchData method with your integration code (in the example here, we fetch tasks from Salesforce):
salesforce-contacts.ts
import { NangoSync, Contact } from './models';

export default async function fetchData(nango: NangoSync): Promise<void> {
    const query = buildQuery(nango.lastSyncDate);
    await fetchAndSaveRecords(nango, query);
    await nango.log('Sync run completed!');
}

function buildQuery(lastSyncDate?: Date): string {
    let baseQuery = `SELECT Id, FirstName, LastName, Email, AccountId, LastModifiedDate FROM Contact`;

    if (lastSyncDate) { // Only fetch the new data.
        baseQuery += ` WHERE LastModifiedDate > ${lastSyncDate.toISOString()}`;
    }

    return baseQuery;
}

async function fetchAndSaveRecords(nango: NangoSync, query: string) {
    let endpoint = '/services/data/v53.0/query';

    while (true) {
        const response = await nango.get({
            endpoint: endpoint,
            params: endpoint === '/services/data/v53.0/query' ? { q: query } : {}
        });

        const mappedRecords = mapContacts(response.data.records);

        await nango.batchSave(mappedRecords, 'SalesforceContact'); // Saves records to Nango cache.

        if (response.data.done) {
            break;
        }

        endpoint = response.data.nextRecordsUrl;
    }
}

function mapContacts(records: any[]): SalesforceContact[] {
    return records.map((record: any) => {
        return {
            id: record.Id as string,
            first_name: record.FirstName,
            last_name: record.LastName,
            email: record.Email,
            account_id: record.AccountId,
            last_modified_date: record.LastModifiedDate
        };
    });
}
In this script, the following Nango utilities are used:
  • nango.lastSyncDate is the last date at which the sync has run
  • await nango.batchSave() to persist external data in Nango’s cache
  • await nango.get() to perform an API request (automatically authenticated by Nango)
  • await nango.log() to print console logs (replaces console.log())
Learn more about sync scripts: understanding syncs, script reference, example templates.

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Write an action script

Open the generated action script (named [action-name].ts) which should contain the following scaffolding :
salesforce-contact-fields.ts
import type { NangoAction, FieldSchema } from './models';

export default async function runAction(nango: NangoAction): Promise<FieldSchema> {
    // Integration code goes here.
}
Fill in the runAction method with your integration code (in the example here, we fetch available contact fields from Salesforce):
salesforce-contact-fields.ts
import type { NangoAction, FieldSchema } from './models';

export default async function runAction(nango: NangoAction): Promise<FieldSchema> {
    try {
        const response = await nango.get({
            endpoint: '/services/data/v51.0/sobjects/Contact/describe'
        });

        await nango.log('Salesforce fields fetched!');

        const { data } = response;
        const { fields, childRelationships } = data;

        return {
            fields: mapFields(fields)
        };
    } catch (error: any) {
        throw new nango.ActionError({
            message: 'Failed to fetch fields in the runAction call',
            details: {
                message: error?.message,
                method: error?.config?.method,
                url: error?.config?.url,
                code: error?.code
            }
        });
    }
}

function mapFields(fields: any) {
    return fields.map((field) => {
        const { name, label, type, relationshipName } = field;
        return {
            name,
            label,
            type,
            relationshipName: relationshipName as string
        };
    });
}
In this script, the following Nango utilities are used:
  • await nango.get() to perform an API request (automatically authenticated by Nango)
  • nango.ActionError() to report errors in the execution of the script
  • await nango.log() to print console logs (replaces console.log())
  • return will synchronously return results from the action trigger request
Learn more about action scripts: understanding actions, script reference, example templates.

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Test your scripts locally

Easily test your scripts locally as you develop them with the dryrun function of the CLI (reference): 
nango dryrun salesforce-contacts '<CONNECTION-ID>' # Sync
nango dryrun salesforce-contact-fields '<CONNECTION-ID>' # Action
nango dryrun --help # Display help for command
Because this is a dry run, syncs won’t persist data in Nango (and actions never persist data); instead, the retrieved data will be printed to the console.
By default, dryrun retrieves connections from your Dev environment.

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Deploy your integration scripts

Nango provides multiple cloud environments so you can test your scripts more thoroughly before releasing them to customers. To deploy all scripts at once, run (reference): 
nango deploy dev # Deploy to your Development environment
# or
nango deploy prod # Deploy to your Production environment
In the Nango UI, navigate to the Scripts tab of the relevant integration(s) to verify the deployment succeeded.
Learn more about scripts.
Questions, problems, feedback? Please reach out in the Slack community.