How to integrate with HubSpot using your Postgres database
The short answer is:
You can integrate your Postgres database with HubSpot for a relatively cheap, code-minimal, and highly flexible solution by using a combination of PostgREST, a server-side Google Tag Manager (GTM) setup with a tool like Stape, and the HubSpot API.
This architecture uses PostgREST to instantly turn your database tables into a RESTful API, allowing data to be pulled out easily.
Then, server-side GTM, hosted affordably by Stape, acts as a low-code processing layer that fetches this data and sends it directly to the HubSpot Events API to create custom activity on contact timelines, like a product_purchase event.
This bypasses the need for custom server-side coding for data transformation and API calls, saving you development time and infrastructure costs.
The long answer is:
That’s a clever and cost-effective approach for getting your backend data into HubSpot, especially when compared to building a complex custom application or paying for an expensive enterprise-grade ETL tool.
The combination of PostgREST, server-side GTM, and the HubSpot API creates a powerful, lightweight, and incredibly flexible pipeline.
The first key component is PostgREST, which is an open-source tool that turns your entire PostgreSQL database into a clean, instantly accessible RESTful API with no coding required, simply by reading the schema and permissions.
Instead of writing custom API endpoints in Python or Node.
js to expose data from your tables, PostgREST does it automatically.
This dramatically cuts down on development time and removes the need for a dedicated backend service to expose your data.
For example, if you have a user_activity table in Postgres, PostgREST instantly creates an endpoint like /user_activity that you can query over HTTP.
Next, you need a way to process the data from this new API and transform it into the specific JSON format that HubSpot’s Events API requires.
This is where server-side GTM comes into play, often hosted on a dedicated, affordable platform like Stape or even on Google Cloud Platform’s minimal tier.
Server-side GTM is a low-code environment that can act as a simple intermediary server.
You can configure a GTM server-side tag to make an HTTP request to your PostgREST endpoint to pull new data, like a new user sign-up or a completed course.
Once GTM has the data, you can use its built-in tools and templates to clean it, reshape it, map the database fields to the correct HubSpot properties, and then construct the final payload for the HubSpot Events API.
The final step is leveraging the HubSpot Events API to create custom activities on your contact records, which is crucial for advanced segmentation, workflows, and reporting.
Instead of just pushing a static property update like “Last Purchased Date” (which doesn’t track history), you can send an event like user_logged_in or course_completed with all the relevant context, like the course name and completion time.
This timeline data is far more valuable for your sales and marketing teams.
The GTM server tag simply sends a POST request with the correctly formatted JSON payload to the HubSpot event completion endpoint.
The reason this is an excellent and cheap solution is threefold: it minimizes custom code because PostgREST handles the API generation and GTM handles the transformation logic, it is highly scalable because both PostgREST and the server-side GTM environment are designed for high performance, and it is cost-effective because the tools involved are either free and open-source (PostgREST, GTM) or offer very low-cost hosting options (Stape, basic cloud VM for PostgREST).
This gives you the control and flexibility of a custom integration without the complexity, time, and expense of a full-stack engineering project.
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