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Business productivity

Connect Resend to any app with two-way sync.

Two-way sync Resend across all your CRMs, databases, data warehouses, EDI systems, and AI tools, with custom workflows tailored to your data.

  • SOC 2 and 6 other compliance frameworks
  • POC with real engineers in minutes

Adopted by fast-scaling companies moving mission-critical data in real time

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Migrated from MuleSoft
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Migrated from Celigo
Migrated from Heroku Connect
Migrated from Matillion
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Migrated from Fivetran
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Migrated from Celigo
Object catalog

What Stacksync syncs in Resend.

These objects sync between Resend and any connected system, with field-level mapping and conflict resolution. Custom fields are picked up from the live schema where Resend exposes them.

Emails
Sent messages retrievable by ID with current delivery status.
Contacts
Recipient records with email, name, and subscription state, synced from CRMs or databases.
Audiences
Named contact lists that broadcasts target; typically mirrored from CRM segments.
Broadcasts
One-to-many campaign sends addressed to an audience.
Domains
Verified sending domains with DNS and DKIM status.
Email events
Delivered, bounced, complained, opened, and clicked events emitted via webhooks and written back to source systems.
API keys
Scoped credentials managed per environment for send and read access.
API surface

How Stacksync connects to Resend.

The connector runs on Resend's native API. Stacksync manages authentication, rate limits, retries, and schema changes so your team does not maintain integration code.

Connection
REST API
Authentication
API key (Bearer token)
Change detection
Webhooks for email lifecycle events; polling for contact and audience state

Sync directions

  • Read Supported
  • Write Supported
  • Change data capture Not available
  • Webhooks Supported
What ships with Resend

Connect Resend for flexible, real-time data sync.

Real-time sync, workflow automation, event queues, EDI, and monitoring, for every connection.

Real-time

Two-way sync

Changes in Resend instantly reflect across connected systems. No stale data, no manual imports.

No-code + pro-code

Workflow automation

Trigger automated workflows whenever Resend data changes, update records, fire webhooks, or kick off sequences without brittle API scripts.

At scale

Event queues

Handle millions of events per minute without losing a single Resend record.

Observability

Monitoring

Track your Resend sync health, view errors, and replay failed events in one click.

Trading partners

EDI

Transform legacy EDI complexity into simple database interactions.

Use cases

What teams run on the Resend connector.

Product engineering and growth or lifecycle marketing teams buy Resend to send transactional and marketing email through a developer-first REST API instead of a legacy ESP. It sits at the delivery edge of the stack: application code and lifecycle tools call it to send, while the customer data behind those sends lives in a CRM, database, or warehouse. Its data gravity comes from what accumulates inside it: Contacts, Audiences, and Email events that other systems need back for suppression and attribution.

  • Product engineering
  • Growth/lifecycle marketing
  • RevOps
  • Developers

  1. Sync CRM contact segments into Resend Audiences so lifecycle broadcasts target current data.

  2. Write delivery, bounce, and complaint events back to the CRM or a Postgres table for deliverability reporting.

  3. Trigger transactional sends when a row changes in an operational database, such as an order status update.

  4. Keep suppression and unsubscribe state synced between Resend and other marketing tools to stay compliant.

  5. Feed open and click events into a warehouse for engagement analytics alongside product data.

  6. Sync CRM or database contact lists into Resend Contacts and Audiences so Broadcasts always target a current, deduplicated recipient list.

All Resend integrations

Pick the system you need to keep in sync with Resend. Each page covers the sync setup, field mapping, and common workflows for that pair.

CRM · 40

ERP · 47

Database · 45

Data warehouse · 30

Business productivity · 26

Accounting and finance · 8

How it works

Set up Resend in minutes, without APIs.

Configure and sync within minutes, no code. Whether you sync 50k or 100M+ records, Stacksync handles the queues, infra, and plumbing. Integrations are non-invasive and need zero setup on your systems.

  1. 01

    Connect your apps

    Authenticate Resend with its native method — OAuth, API keys, or service accounts — plus secure options like SSH tunneling, IP whitelisting, and VPC peering.

    • OAuth 2.0
    • SSH tunnel
    • VPC peering
    Resend connected
    OAuth 2.0
    SSH tunnel
    SSL certificate
    VPC peering
  2. 02

    Choose tables

    Pick the Resend objects to sync — Stacksync auto-detects the schema, including custom fields where the platform exposes them. Sync to existing tables, or let Stacksync create new ones with ideal data types.

    • Standard objects
    • Custom objects
    • Auto-schema
    objects · Resend
    Customers 12,480
    Sales Orders 8,213
    Invoices 5,902
    Items 1,344
  3. 03

    Map fields

    Fields map automatically even when names and types differ. Stacksync handles transformation and type casting for you, zero configuration required.

    • Auto-map
    • Type casting
    • Transforms
    Resend database
    Company company_name text
    Email email text
    Amount amount numeric
    Created created_at timestamp
Try interactive demo

FAQ

Resend connector FAQ

What can I sync with the Resend connector?

Resend's core objects — Emails, Contacts, Audiences, Broadcasts and custom fields — can sync with any of 196 other systems. Every integration is real-time and bidirectional, with field-level mapping and conflict resolution.

How does Stacksync connect to Resend?

Via REST API, authenticated with API key (Bearer token). Changes are detected as follows — webhooks for email lifecycle events; polling for contact and audience state. Stacksync manages rate limits, retries, and schema changes automatically.

Is the Resend connector two-way?

Yes. Changes made in Resend propagate to the connected system and vice versa, in milliseconds. One-way flows are also supported when a direction should stay read-only.

How long does a Resend integration take to set up?

Most Resend integrations go live in minutes: authenticate Resend and the other system, pick objects and fields, and enable the sync. No code and no infrastructure to manage.

Is Resend data secure in transit?

Stacksync is SOC 2 Type II, ISO 27001, GDPR and HIPAA compliant. Resend data is encrypted in transit, and a zero-persistent-storage architecture means records are not retained after a sync operation.

SECURITY

Security teams trust Stacksync

As a data company, we understand the importance of keeping your data secure. Stacksync is built with security best practices to keep your data safe at every layer, and is DPF-certified for US, EU, UK and CH data transfers.

Learn more about security
SOC 2 Type II
ISO 27001
HIPAA BAA
GDPR
CCPA
CSA STAR
DPF US-EU-UK-CH
→ SECURITY WITH BENEFITS

SSO & SCIM

Let your users access Stacksync from your centralized user management systems. Works with Okta, Azure, Google SSO and more.

Alerts

Immediately get alerted about record syncing issues over email, Slack, PagerDuty and WhatsApp. Resolve issues from a centralized dashboard with retry and revert options.

Secure connection options

Securely connects to your systems with:

OAuth 2 SSH Tunnelling SSL certificates IP Whitelisting VPN gateway VPC peering and more
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