When you need Salesforce to work with data stored in PostgreSQL, Heroku Connect and ForceCnx take fundamentally different approaches. Heroku Connect copies data between Heroku Postgres and Salesforce using bidirectional sync. ForceCnx exposes your database as a managed OData 4.0 endpoint that Salesforce reads in real time via External Objects. This page breaks down the practical differences to help you choose the right tool.
How Heroku Connect Works
Heroku Connect is an add-on for the Heroku platform that synchronizes data between a Heroku Postgres database and a Salesforce org. You configure mappings between Salesforce objects and PostgreSQL tables, and Heroku Connect keeps them in sync using polling or Salesforce's Streaming API (Change Data Capture).
Data flows in one or both directions. In read-only mode, Salesforce data is copied down to Heroku Postgres so your web application can query it locally. In write-back mode, changes made in PostgreSQL are pushed back to Salesforce. The sync frequency depends on your configuration and plan, but there is always some latency between a change in one system and its reflection in the other.
Heroku Connect requires that your PostgreSQL database runs on Heroku. You cannot point it at a Cloud SQL instance, an Amazon RDS database, or a self-hosted PostgreSQL server. Your application and database must live within the Heroku ecosystem.
How ForceCnx Works
ForceCnx takes the opposite approach. Instead of copying data into Salesforce, it lets Salesforce read your database in real time. ForceCnx connects to your PostgreSQL, Google Cloud SQL, or Amazon RDS database, generates a compliant OData 4.0 endpoint, and Salesforce Connect consumes that endpoint as External Objects.
When a Salesforce user opens a record backed by an External Object, Salesforce queries the OData endpoint at that moment, and ForceCnx translates the request into a SQL query against your database. The data is always current because it is always fetched live. Nothing is copied, cached, or stored in Salesforce.
Head-to-Head Comparison
| Dimension | Heroku Connect | ForceCnx | |---|---|---| | Data architecture | Copies data (bidirectional sync) | Real-time reads (no data movement) | | Data freshness | Minutes to hours of sync latency | Real-time, always current | | Salesforce storage | Synced data counts against org storage limits | Zero — External Objects store no data | | Database requirement | Heroku Postgres only | PostgreSQL, Cloud SQL, Amazon RDS | | Hosting requirement | Application must run on Heroku | No hosting requirement | | Write-back to Salesforce | Yes, bidirectional sync supported | No — External Objects are read-only | | Write to external DB | Via your Heroku app | Not through Salesforce Connect | | Setup complexity | Moderate — configure mappings, manage Heroku app | Low — configure connection, select tables | | Pricing model | Per-connection rows synced + Heroku hosting | Subscription (free tier available) | | Platform future | Salesforce is phasing out Heroku | Independent SaaS, actively developed | | Salesforce automation | Full — synced data is native objects | Limited — External Objects do not trigger flows | | Offline access | Data stored in Salesforce, available offline | Requires connectivity to external database |
When to Choose Heroku Connect
Heroku Connect remains the right choice in specific scenarios, particularly when bidirectional data flow is a hard requirement.
When you need write-back to Salesforce. If your external application creates or modifies Salesforce records and you need those changes reflected in the Salesforce org, Heroku Connect's bidirectional sync handles this natively. ForceCnx and Salesforce Connect External Objects are read-only.
When Salesforce automation must fire on external data changes. Workflow rules, flows, and Apex triggers only run on standard and custom objects, not External Objects. If your business logic depends on Salesforce automation firing when external data changes, you need that data synced into Salesforce as native objects.
When your application already runs on Heroku. If you have an existing Heroku application with a Heroku Postgres database and you are already paying for the Heroku ecosystem, adding Heroku Connect is a natural extension. The tight integration with Heroku's platform makes setup straightforward.
When offline access matters. Because Heroku Connect copies data into Salesforce, that data is available even when the external database is unreachable. For mobile users in areas with intermittent connectivity, this can be important.
When to Choose ForceCnx
ForceCnx is the stronger choice when real-time data access, cost control, and infrastructure flexibility are priorities.
When data freshness matters. Heroku Connect's sync introduces latency. If your users need to see inventory levels, order statuses, pricing, or other fast-changing data as it currently exists in your database, real-time External Objects deliver that without waiting for the next sync cycle.
When you want to avoid Salesforce storage costs. Syncing large volumes of data into Salesforce with Heroku Connect means paying for that storage in your Salesforce org. External Objects consume zero storage regardless of how many rows exist in your database. For large datasets, this difference is significant.
When your database is not on Heroku. Heroku Connect only works with Heroku Postgres. If your data lives in Amazon RDS, Google Cloud SQL, or any other PostgreSQL host, Heroku Connect is not an option. ForceCnx connects to PostgreSQL wherever it runs.
When you want platform independence. Heroku Connect ties you to the Heroku ecosystem. Salesforce has been deprioritizing Heroku, sunsetting features, and shifting investment toward other platforms. Building a critical integration on Heroku Connect carries platform risk. ForceCnx is an independent service with no dependency on Heroku's roadmap.
When you want simplicity. ForceCnx requires no application hosting, no Heroku dynos, no add-on management. You configure your database connection, select tables, and get a working OData endpoint. There is no infrastructure to manage beyond your own database.
When cost is a concern. Heroku Connect pricing scales with the number of rows synced and requires a paid Heroku plan for production use. Combined with Heroku Postgres, dyno costs, and Salesforce storage for synced data, the total cost adds up. ForceCnx offers a free tier and straightforward subscription pricing without additional infrastructure costs.
Bottom Line
Heroku Connect and ForceCnx solve the same core problem (getting external PostgreSQL data into Salesforce) but with opposite architectures. Heroku Connect copies data bidirectionally, giving you native Salesforce objects with full automation support at the cost of sync latency, storage consumption, and Heroku lock-in. ForceCnx reads data in real time via External Objects, giving you zero storage cost, always-current data, and database flexibility at the cost of read-only access and limited Salesforce automation.
If you need bidirectional sync and Salesforce automation on external data, Heroku Connect is built for that. For everything else, especially read-heavy integrations where freshness and cost matter, ForceCnx delivers a simpler, cheaper, and more future-proof solution. And with Heroku's uncertain roadmap, the platform risk of Heroku Connect is worth weighing in any long-term integration decision.