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Customer.io to Ironclad integration — real-time, two-way sync

Keep Customer.io and Ironclad in sync without custom scripts. Cut weeks of integration work, eliminate silent data drift, and give your team a single, reliable source of truth.

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

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Why teams connect Customer.io and Ironclad

Stop re-entering the same information in Customer.io and Ironclad: Stacksync keeps the records they share consistent in real time, in both directions.

Two tools in the daily stack often hold overlapping information: the same people, the same companies, or the same pieces of work, described twice. The tools do different jobs, so consolidating is not the answer; the overlap just needs to stop drifting.

Stacksync syncs Broadcasts, Deliveries / Messages, Newsletters, People in Customer.io with Signature Packets, Workflow Documents, Workflows, Records in Ironclad in real time. You choose which records overlap, map the fields that should match, and pick a direction or let changes flow both ways. From then on, an update made in either tool is reflected in the other within seconds, without exports or copy-paste.

Because the sync is field-level, each tool keeps its own extras; only the shared data is held in agreement.

Common use cases

  • 01 Sync account-level objects and their person relationships for B2B messaging keyed to company attributes.
  • 02 Sync product usage and billing attributes from Postgres onto Customer.io people so lifecycle campaigns trigger on real product behavior.
  • 03 Stream workflow approval and signature webhook events into an operational database for cycle-time, bottleneck, and SLA reporting across the contract lifecycle.
  • 04 Push Obligations and renewal dates from Ironclad into a finance or task system so post-signature commitments and renewals are tracked and actioned on time.

Common sync patterns

Handoffs between teams

When work started in one tool continues in the other, the shared fields travel with it automatically.

Where both tools track people or companies: one consistent record

Contact and company details corrected in either tool update the other, so nobody works from the old version.

Where one tool produces events: mirror them in the other

Payments, replies, messages, or tickets created in one tool can create or update matching records in the other, keeping context in one place.

What you can sync between Customer.io and Ironclad

Representative objects on each side — any object or custom field can map to any target. Schemas are auto-detected; types are converted between the two systems.

Customer.io objects Ironclad objects How this pairing syncs
Segments Attribute- or event-based groups; data syncs feed the attributes segments evaluate. Workflow Approvals Per-workflow approval requests and their state; read to report approval status and cycle time, and status changes arrive live through the workflow_approval_status_changed event. Segments is specific to Customer.io and Workflow Approvals to Ironclad — each maps to any object or custom field on the other side.
Campaigns Automated workflows whose membership and metrics can be read via the App API. Signature Packets The e-signature packets on a workflow (sent, signatures collected, fully signed); read to track signing progress, with packet events delivered by webhook for real-time status. Campaigns is specific to Customer.io and Signature Packets to Ironclad — each maps to any object or custom field on the other side.
Broadcasts One-off sends to segments or audiences, triggerable via API. Workflow Documents Draft and executed documents attached to a workflow; retrieved to pull generated or signed files out into a document store or archive. Broadcasts is specific to Customer.io and Workflow Documents to Ironclad — each maps to any object or custom field on the other side.
Deliveries / Messages Per-recipient message records whose lifecycle events flow out through reporting webhooks. Workflows The core unit of Ironclad: a live contract process (NDA, MSA, order form) moving through creation, review, approval, and signature. Launched via POST, updated via PATCH, and read for status, so contract processes move two-way between Ironclad and a database, CRM, or ERP. Deliveries / Messages is specific to Customer.io and Workflows to Ironclad — each maps to any object or custom field on the other side.
Newsletters Recurring email sends with performance metrics available for reporting syncs. Records The Repository of executed and stored contracts with metadata (value, counterparty, key dates, type) and attachments; full create, read, update, and delete so signed-contract data and PDFs sync to a warehouse, ERP, or CRM. Newsletters is specific to Customer.io and Records to Ironclad — each maps to any object or custom field on the other side.
People Profiles with attributes, matched on identifiers like id or email; the main write target of data syncs. Entities Structured records for counterparties and other parties linked to workflows and records; read and written to keep company and vendor master data aligned with a CRM or ERP. People is specific to Customer.io and Entities to Ironclad — each maps to any object or custom field on the other side.

How changes propagate between Customer.io and Ironclad

Each direction of the sync is driven by what the source system can signal and what the destination accepts — detection, delivery, and expected latency below.

Customer.io Ironclad Sub-second propagation

DetectionCustomer.io notifies Stacksync of record changes through webhook events. Reporting webhooks push message and delivery events.

DeliveryEach detected change is written to Ironclad through its API, with automatic retries and rate-limit backoff.

Ironclad Customer.io Sub-second propagation

DetectionIronclad notifies Stacksync of record changes through webhook events. Native webhook subscriptions (POST /webhooks) fire on 40+ workflow, approval, signature, document, and comment events, and Ironclad retries a failing.

DeliveryEach detected change is written to Customer.io through its API, with automatic retries and rate-limit backoff.

Rate-limit considerations

  • Customer.io: Subject to per-API rate limits documented by Customer.io.
  • Ironclad: Limits are enforced per account per minute by endpoint: GET Workflows 400 and POST/PATCH Workflows 40; GET Records 600 and POST/PATCH Records 200; GET Entities 600 and POST/PATCH Entities 200; Webhooks 600; all other endpoints 800. Exceeding a limit returns HTTP 429, and Ironclad recommends exponential backoff with jitter.
What ships with Customer.io ⇄ Ironclad

Connect Customer.io and Ironclad for flexible, real-time data sync.

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

Real-time

Two-way sync

Changes in Customer.io or Ironclad instantly reflect in both systems. No stale data, no manual imports.

No-code + pro-code

Workflow automation

Trigger automated workflows whenever Customer.io or Ironclad 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 Customer.io or Ironclad record.

Observability

Monitoring

Track your Customer.io ⇄ Ironclad sync health, view errors, and replay failed events in one click.

Trading partners

EDI

Transform legacy EDI complexity into simple database interactions between Customer.io and Ironclad.

How the Customer.io and Ironclad connectors work

Customer.io

Integration surface
REST APIs split by purpose: Track API for data ingestion, App API for campaigns, people lookups, and messages
Authentication
Basic auth with site ID and API key for the Track API; bearer token for the App API
Change detection
Reporting webhooks push message and delivery events; person attribute changes are not streamed and require source-side detection
Capabilities
read · write · webhooks
Rate limits
Subject to per-API rate limits documented by Customer.io

Ironclad

Integration surface
REST/JSON Public API (CLM API) at https://na1.ironcladapp.com/public/api/v1 (NA1 and EU1 regions plus a demo/sandbox), with a native Webhooks subscription API; described by an OpenAPI 3.1 spec.
Authentication
OAuth 2.0 - Authorization Code grant (PKCE for public clients) and Client Credentials grant for server-to-server; access tokens are Bearer, expire after 6 hours, and every endpoint is gated by a resource scope. The legacy static API bearer token was deprecated on 2024-11-22.
Change detection
Native webhook subscriptions (POST /webhooks) fire on 40+ workflow, approval, signature, document, and comment events, and Ironclad retries a failing endpoint up to 10 times over about 13.6 hours with exponential backoff. Otherwise poll the list endpoints by last-updated. There is no database change-data-capture log.
Capabilities
read · write · webhooks
Rate limits
Limits are enforced per account per minute by endpoint: GET Workflows 400 and POST/PATCH Workflows 40; GET Records 600 and POST/PATCH Records 200; GET Entities 600 and POST/PATCH Entities 200; Webhooks 600; all other endpoints 800. Exceeding a limit returns HTTP 429, and Ironclad recommends exponential backoff with jitter.
How it works

How to connect Customer.io to Ironclad — three steps, no code

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 Customer.io and Ironclad with each platform's 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
    Customer.io connected
    Ironclad connected
    OAuth 2.0
    SSH tunnel
    SSL certificate
    VPC peering
  2. 02

    Choose tables

    Pick the Customer.io and Ironclad objects to sync — Stacksync auto-detects both schemas, 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 · Customer.io ⇄ Ironclad
    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
    Customer.io Ironclad
    Company company_name text
    Email email text
    Amount amount numeric
    Created created_at timestamp
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FAQ

Customer.io and Ironclad integration FAQ

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
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DPF US-EU-UK-CH
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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

Related integrations

Every pair below is a real-time, two-way sync. Search all 422 integrations available for Customer.io and Ironclad.

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