How to Sync Leads into Audiences and Trigger Campaigns Across Marketing Platforms using a Unified Marketing API

April 10, 2026

If you need to integrate with tools like HubSpot, Mailchimp, Klaviyo, ActiveCampaign, or Customer.io, you need a consistent way to sync leads, assign them to audiences, trigger campaigns, and retrieve performance data—without building separate integrations for each API.

This guide shows how to implement that workflow using a unified Marketing API.

Use case: sync leads → assign audiences → trigger campaigns → measure performance

Build a marketing integration that:

• syncs leads into marketing platforms
• assigns leads to audiences (lists)
• creates campaigns targeting those audiences
• retrieves campaign performance metrics

All through a single normalized API.

Core objects

Step 1: List audiences

Before syncing leads or creating campaigns, retrieve available lists.

const lists = await sdk.martech.listMartechLists({
  connectionId,
  limit: 100,
  offset: 0,
  sort: 'updated_at',
  order: 'asc',
  fields: ['id', 'name', 'is_active'],
});

Each list represents an audience that can be:

• assigned to members via list_ids
• targeted by campaigns via list_ids

Step 2: Create a member (lead)

Create a new lead using normalized member fields.

const member = await sdk.martech.createMartechMember({
  connectionId,
  martechMember: {
    first_name: 'Jane',
    last_name: 'Doe',
    emails: [
      {
        email: 'jane@example.com',
        type: 'WORK',
      },
    ],
    status: 'SUBSCRIBED',
  },
  fields: ['id', 'emails', 'status', 'list_ids'],
});

Writable fields include:

• emails
• first_name, last_name
• status
• list_ids
• tags

Step 3: Assign the member to audiences

Audience membership is handled directly on the member.

const updatedMember = await sdk.martech.updateMartechMember({
  connectionId,
  id: member.id,
  martechMember: {
    list_ids: ['list_123'],
    tags: ['trial-user'],
    status: 'SUBSCRIBED',
  },
  fields: ['id', 'list_ids', 'tags', 'status'],
});

This step:

• attaches the lead to one or more lists
• sets subscription state
• adds segmentation metadata via tags

There is no separate membership endpoint required.

Step 4: Create a campaign targeting those audiences

Campaigns are created with list_ids as the targeting mechanism.

const campaign = await sdk.martech.createMartechCampaign({
  connectionId,
  martechCampaign: {
    name: 'Welcome Campaign',
    type: 'regular',
    status: 'SCHEDULED',
    list_ids: ['list_123'],
    subject_line: 'Welcome to the platform',
    preview_text: 'Here's what to do next',
    from_name: 'Acme',
    from_email: 'team@acme.com',
    reply_to_email: 'support@acme.com',
    send_at: new Date().toISOString(),
  },
  fields: [
    'id',
    'status',
    'list_ids',
    'subject_line',
    'send_at',
  ],
});

Campaign status values include:

• DRAFT
• SCHEDULED
• SENDING
• SENT
• CANCELLED
• PAUSED
• ARCHIVED

Step 5: Retrieve campaign state

Campaigns should be treated as stateful objects.

const latestCampaign = await sdk.martech.getMartechCampaign({
  connectionId,
  id: campaign.id,
  fields: ['id', 'status', 'updated_at'],
});

You can also retrieve campaigns incrementally:

const campaigns = await sdk.martech.listMartechCampaigns({
  connectionId,
  updated_gte: lastSyncAt,
  limit: 100,
  offset: 0,
  sort: 'updated_at',
  order: 'asc',
  fields: ['id', 'status', 'list_ids', 'updated_at'],
});

Step 6: Retrieve campaign performance (reports)

Reports provide normalized performance metrics across platforms.

const reports = await sdk.martech.listMartechReports({
  connectionId,
  campaign_id: campaign.id,
  limit: 100,
  offset: 0,
  sort: 'updated_at',
  order: 'asc',
  fields: [
    'campaign_id',
    'emails_sent',
    'unsubscribed',
    'hard_bounces',
    'soft_bounces',
    'opens_total',
    'unique_opens',
    'open_rate',
    'clicks_total',
    'unique_clicks',
    'click_rate',
  ],
});

Available metrics include:

• delivery (emails_sent, bounces)
• engagement (opens_total, clicks_total)
• rates (open_rate, click_rate)
• list impact (unsubscribed)

You can filter reports by:

• campaign_id
• list_id
• start_gte
• end_lt

Step 7: Maintain state incrementally

All major endpoints support incremental sync via updated_gte.

Example for members:

const members = await sdk.martech.listMartechMembers({
  connectionId,
  updated_gte: lastSyncAt,
  limit: 100,
  offset: 0,
  sort: 'updated_at',
  order: 'asc',
  fields: ['id', 'emails', 'list_ids', 'status', 'updated_at'],
});

Use the same pattern for:

• campaigns
• lists
• reports

This avoids full re-syncs and keeps data current.

Step 8: Webhooks and polling strategy

Webhook support varies by object and integration.

Member

• created and updated events are widely supported
• use webhooks as the primary update mechanism
• use polling (updated_gte) as fallback

List

• partial webhook support
• rely on polling for consistency

Campaign

• inconsistent webhook support
• treat polling as the source of truth

Report

• retrieved via API
• use polling for updates

End-to-end flow

const lists = await sdk.martech.listMartechLists({ connectionId });

const member = await sdk.martech.createMartechMember({
  connectionId,
  martechMember: {
    emails: [{ email: 'jane@example.com' }],
    status: 'SUBSCRIBED',
  },
});

await sdk.martech.updateMartechMember({
  connectionId,
  id: member.id,
  martechMember: {
    list_ids: ['list_123'],
  },
});

const campaign = await sdk.martech.createMartechCampaign({
  connectionId,
  martechCampaign: {
    name: 'Welcome Campaign',
    list_ids: ['list_123'],
    status: 'SCHEDULED',
  },
});

const reports = await sdk.martech.listMartechReports({
  connectionId,
  campaign_id: campaign.id,
});

Key takeaways

• Audience membership and campaign targeting both use list_ids
• Lead sync and audience assignment are part of the same write flow
• Campaigns must be treated as stateful objects
• Reports provide a normalized performance layer across platforms
• Member updates can be handled with webhooks, while campaigns and reports require polling
• Incremental sync with updated_gte is required for consistency across integrations

This structure lets you support multiple marketing platforms with one implementation, while maintaining consistent lead data, audience targeting, and campaign performance tracking.

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