SQL Server Integration Services (SSIS) is Microsoft's long-standing ETL platform, shipped as a component of SQL Server. For two decades it has been the default way Microsoft-centric shops extract, transform, and load data - moving data between databases, flat files, and applications with a visual designer and a mature runtime. If your data lives in SQL Server and your team works in the Microsoft stack, SSIS is the tool that's already in the box.
Control flow and data flow
An SSIS package is built from two layers. The control flow orchestrates tasks - execute SQL, move files, run a data flow, send mail, loop over items - with precedence constraints that decide what runs on success or failure. Inside it, the data flow does the row-level work: a source, a series of transformations (lookups, derived columns, merges, conditional splits, slowly changing dimension handling), and a destination. You design both visually in SQL Server Data Tools (an extension of Visual Studio), producing .dtsx package files.
Deployment and execution
Packages deploy to the SSIS catalog (the SSISDB database) on a SQL Server instance, where they're versioned, parameterized per environment, and run on a schedule via SQL Server Agent. For teams moving to the cloud, Azure Data Factory offers an SSIS Integration Runtime that lifts and shifts existing packages to run in Azure - a migration path that lets long-lived SSIS investments keep working without a rewrite.
Where it fits
- Microsoft-centric organizations with data in SQL Server and the broader Microsoft data stack.
- On-prem ETL with rich transformation logic, slowly changing dimensions, and complex control flow.
- Teams with existing SSIS packages wanting a managed cloud path via Azure Data Factory.
When to look elsewhere
SSIS is firmly an on-prem, Microsoft-stack tool. For loading cloud SaaS sources into a modern warehouse, managed ELT like Fivetran is far less to build and maintain. Teams standardizing on ELT and transformation-as-code with dbt, or working primarily outside the Microsoft ecosystem, will find SSIS a heavier and more dated fit.
How it compares
Among classic visual ETL tools, SSIS is the Microsoft counterpart to Informatica PowerCenter and Talend - strong on transformation and control flow, rooted on-prem. Its advantage is being bundled with SQL Server and deeply integrated with it; its limitation is that pull toward the Microsoft world and away from cloud-native ELT patterns.
Frequently asked questions
Is SSIS free? It is included with SQL Server licenses rather than sold separately, so cost is tied to your SQL Server edition.
Can SSIS run in the cloud? Yes - Azure Data Factory provides an SSIS Integration Runtime to run existing packages in Azure.
What is a data flow in SSIS? The part of a package that performs row-level ETL: reading from sources, applying transformations, and writing to destinations.