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Many organizations use more than one software system to run their business. A company might manage customer relationships in one tool and track inventory or orders in another.
When these systems share data, it is important that the information stays aligned. If a customer's phone number changes in one system but not the other, it can create confusion or errors.
This article explains how two way sync works. It covers how data moves between systems, how conflicts are handled, and what makes this process reliable and secure.
Two way sync, also called bidirectional synchronization, is a method that keeps data consistent between two systems by updating both whenever changes happen in either one.
In a two way sync setup:
Dual direction updates: Changes made in System A automatically apply to System B, and vice versa
Consistency maintenance: Both systems remain aligned without manual intervention
Automated data flow: Human error from manual data entry is eliminated
Two way sync uses automated triggers to detect changes and update the other system. These triggers can include scheduled checks or instant alerts when data is updated.
Data mapping defines how fields in one system relate to fields in the other. If one system uses "First Name" and another uses "Given Name," the sync process handles that translation.
Two way sync also includes logic for conflict resolution. If the same record is changed in both systems at the same time, the sync tool applies a rule to decide which change to keep.
One-way sync moves data from one system to another without sending updates back. It works like a one-way street where information flows in a single direction. Two way synchronization allows both systems to send and receive changes, like a two-way street where traffic flows in both directions.
Feature | One-Way Sync | Two-Way Sync (or 2 way sync) |
|---|---|---|
Direction of data flow | Single direction | Both directions |
Use cases | Backups, reporting | Collaboration, shared databases |
Complexity | Lower | Higher |
Conflict management | Rarely needed | Essential |
Resource requirements | Fewer resources | More resources |
Typical applications | Data warehousing, exports | CRM-ERP integration, ticketing |
One-way sync is simpler to set up and manage. Conflict handling is not required because only one system changes the data.
Two way sync requires more setup and processing. Changes in both systems may happen at the same time, so conflict resolution logic is necessary to decide which version is kept.
Each method serves different use cases. Selecting between them depends on how data is used across systems.
Bidirectional sync solves real business problems by ensuring data consistency across different systems. Here are three common applications:
Customer relationship management (CRM) systems and enterprise resource planning (ERP) systems often store overlapping data. Two-way sync allows both systems to reflect updates made in either one.
For example:
A sales representative changes a customer's address in the CRM, and the ERP system receives the same update
The finance team updates a payment status in the ERP, and that update appears in the CRM
Product availability changes in the ERP are visible to sales teams in the CRM
This integration helps teams work with accurate information regardless of which system they use.
Marketing teams need current customer data to create effective campaigns. Two way synchronization connects marketing platforms with operational databases to keep information current in both systems.
When a customer submits a new email address on a website, that information updates both the marketing platform and the operational database. If the marketing platform records a response to a campaign, that data transfers back to the database where other systems can access it.
Support teams and sales teams often use different software systems. Two-way sync connects these systems so both teams see the same customer support activity.
When a customer submits a ticket in a help desk system like Zendesk, that ticket appears in the CRM system like Salesforce. If the ticket status changes in either system, the update appears in the other system. This reduces confusion and prevents duplicate responses.
Two-way sync connects systems so that when data changes in one system, the same change automatically appears in the other. Here's how the process typically works:
The first step involves examining how each system stores and organizes information. This includes looking at field names, data types, and relationships between different data elements.
For example, a CRM might store customer information in a "Contacts" table with fields like "First Name" and "Last Name," while an ERP might use a "Customers" table with a single "Full Name" field. Understanding these differences helps plan how data will move between systems.
Field mapping creates connections between related data in each system. For each field in System A, a corresponding field is identified in System B.
Sometimes data needs transformation during the sync process. For instance, if one system stores dates as "MM/DD/YYYY" and another uses "YYYY-MM-DD," the sync process converts between these formats to maintain consistency.
Synchronization starts when something triggers the process. Common triggers include:
Webhooks: Instant notifications when data changes
API polling: Regular checks for changes at set intervals
Scheduled jobs: Sync processes that run at specific times
The choice depends on how quickly updates need to appear in both systems. Real-time sync uses webhooks for immediate updates, while scheduled sync might run hourly or daily for less time-sensitive data.
When the same record changes in both systems before synchronization occurs, a conflict happens. Conflict resolution rules determine which version to keep:
Timestamp-based: The most recent change wins
System priority: One system always takes precedence
Field-level rules: Different rules for different fields
Manual resolution: A person decides which version to keep
These rules prevent data loss and ensure consistent information across systems.
After setup, the sync process requires monitoring to ensure it continues working correctly. This includes checking for errors, failed syncs, and unexpected changes.
Logs track what happened during each sync, making it easier to troubleshoot problems. As systems change over time, the sync configuration may need updates to accommodate new fields or changed data structures.
Conflicts occur in 2 way sync when the same record changes in both systems before synchronization happens. Without proper handling, these conflicts can lead to data inconsistency or loss.
Timestamp-based resolution keeps the most recent change, assuming newer information is more accurate. This works well for straightforward updates like address changes or phone numbers.
Field-level resolution applies different rules to different types of data. For example, customer contact information might always update from the CRM, while billing information always updates from the ERP. This approach recognizes that certain systems serve as the primary source for specific data types.
User-driven resolution involves a person reviewing conflicting changes and deciding which to keep. This method works best for complex or sensitive information where automated rules might not make the right choice.
Data validation checks information before it syncs to ensure it meets quality standards. This includes:
Verifying that required fields contain data
Checking that data formats match expectations (email addresses, phone numbers)
Identifying and removing duplicate records
Confirming that values fall within acceptable ranges
These validation steps prevent invalid data from spreading between systems, maintaining data integrity throughout the synchronization process.
As data volume grows, two way sync systems need strategies to handle the increased load. Batching processes multiple records together instead of one at a time, while incremental updates focus only on data that has changed since the last sync.
Most systems connect through APIs (Application Programming Interfaces), which often limit how many requests can be made in a given time period. Sync processes manage these limits through:
Throttling: Controlling the rate of requests
Backoff strategies: Temporarily slowing down when approaching limits
Queue management: Organizing updates by priority
Security remains essential throughout the synchronization process. Data encryption protects information as it moves between systems (in transit) and while it sits in each system (at rest). Secure connection protocols like HTTPS provide additional protection during data transfer.
Organizations in regulated industries must ensure their sync processes comply with relevant laws and standards:
Access controls determine who can view or modify the sync configuration and monitor the process. Strong authentication methods verify user identities, while role-based permissions limit what actions each user can perform.
Two way sync creates a foundation for integrated data ecosystems where information flows freely between systems. This approach eliminates data silos and ensures teams work with consistent, up-to-date information.
Organizations implementing bidirectional sync typically experience several benefits:
Reduced manual data entry: Information enters once and updates everywhere
Fewer data discrepancies: Systems maintain consistent records
Improved collaboration: Teams access the same information regardless of which system they use
Faster processes: Automated updates eliminate waiting for manual data transfers
The technology behind two way synchronization continues to evolve, with improvements in areas like conflict resolution, performance optimization, and security. These advances make synchronization more reliable and easier to implement.
Integration platforms simplify the process of setting up two way sync between common business systems. These platforms provide pre-built connectors that handle the technical details of connecting systems and mapping data fields.
As organizations grow more complex and use more specialized software tools, the need for effective data integration increases. Two way sync offers a practical approach to keeping information consistent across these diverse systems.
Two way sync manages large data volumes by breaking information into smaller batches, using incremental updates that only sync changed records, and prioritizing critical data. These techniques reduce processing requirements and maintain performance even with millions of records.
Security measures include encryption for data in transit and at rest, secure connection protocols like HTTPS, access controls that limit who can configure and monitor the sync, and audit logs that track all system activities and changes.
Systems without native connectors can be integrated using third-party integration platforms, middleware solutions that sit between systems to facilitate data exchange, or custom API development that creates the necessary connections between systems.
Real-time sync updates information immediately when changes occur using webhooks or similar technologies, while scheduled sync checks for and applies changes at predetermined intervals such as hourly or daily, based on the urgency of keeping systems updated.
Troubleshooting begins with reviewing system logs to identify specific errors, checking for data format issues or validation failures, verifying API connections and credentials, and ensuring field mappings remain correct if either system has been updated.
