Babelfish for Aurora PostgreSQL

Run Microsoft SQL Server applications on PostgreSQL with little to no code change

Babelfish for Aurora PostgreSQL is a new capability for Amazon Aurora PostgreSQL-Compatible Edition that enables Aurora to understand commands from applications written for Microsoft SQL Server.

Migrating from legacy SQL Server databases can be time-consuming and resource-intensive. When migrating your databases, you can automate the migration of your database schema and data using the AWS Database Migration Service (DMS), but there is often more work to do to migrate the application itself, including re-writing application code that interacts with the database.

With Babelfish, Aurora PostgreSQL now understands T-SQL, Microsoft SQL Server's proprietary SQL dialect, and supports the same communications protocol, so your apps that were originally written for SQL Server can now work with Aurora with fewer code changes. As a result, the effort required to modify and move applications running on SQL Server 2005 or newer to Aurora is reduced, leading to faster, lower-risk, and more cost-effective migrations.

Babelfish is a built-in capability of Amazon Aurora, and does not have an additional cost. You can enable Babelfish on your Amazon Aurora cluster with a just few clicks in the RDS management console.

Accelerate SQL Server migrations with Babelfish for Aurora PostgreSQL | Amazon Web Services (1:32)


Reduce migration time and risk

With Babelfish, Amazon Aurora PostgreSQL supports commonly used T-SQL language and semantics which reduces the amount of code changes related to database calls in an application. As a result, the amount of application code you need to re-write is minimized, reducing the risk of any new application errors.

Migrate at your own pace

With Babelfish, you can run SQL Server code side-by-side with new functionality built using native PostgreSQL APIs. Babelfish enables Aurora PostgreSQL to work with commonly-used SQL Server query tools, commands, and drivers. As a result, you can continue developing with the tools you are familiar with.

Babelfish for PostgreSQL Open Source Project is now available

Babelfish source code is now available on GitHub under both the Apache 2.0 license and PostgreSQL license. You can use Babelfish under either license.

Learn more »

How it works

Babelfish implements support for commonly used SQL Server language and semantics (T-SQL) enabling your legacy applications to communicate with Aurora without extensive code re-writes.


Diligent is the leading Governance, Risk, and Compliance (GRC) SaaS company, empowering more than 1 million users and 700,000 board members and leaders to make better decisions, faster. The Diligent One Platform helps organizations connect their entire GRC practice — including governance, risk, compliance, audit and ESG — to bring clarity to complex risk, stay ahead of regulatory changes and deliver impactful insights, in one consolidated view.

"A large majority of Diligent products are built on SQL Server databases. With Babelfish we were able to accelerate our SQL Server application migrations to Aurora PostgreSQL-Compatible Edition, saving us thousands of developer hours which would have been required for manual migrations. Babelfish enables Aurora PostgreSQL to understand SQL Server dialect (T-SQL) and protocol, so our SQL Server applications could be migrated with little or no code change, and AWS offers the Babelfish capability free of charge. We also used Babelfish Compass, an open source standalone tool, which quickly analyzed our T-SQL SQL/DDL scripts for compatibility. Using Babelfish allowed us to drastically reduce the overall infrastructure cost associated with Diligent’s migration to AWS. In addition, with our migration to Aurora PostgreSQL using Babelfish, we are now utilizing Amazon Aurora Serverless v2. By leveraging Aurora Serverless v2, we modernized our databases to scale automatically, reduced operational overhead, and lowered our backup costs by 78%.”

Satheesh Ravala, CTO - Diligent

FactSet enables tens of thousands of investment professionals around the world with the data and analytics they need to make crucial decisions. FactSet creates flexible data and software solutions and leverages Babelfish for Amazon Aurora PostgreSQL-Compatible Edition in production as part of its technology stack. 

“FactSet is excited about Babelfish for Aurora PostgreSQL. Babelfish materially accelerated the pace of a set of migration initiatives from commercial relational databases to PostgreSQL on Amazon Aurora and modernized our data infrastructure without the burden of converting all of our application code as we normally would. As a result, our database and application teams can focus on revenue generating product features rather than rewriting queries."

Wilson Tsai, Senior Director of Engineering - FactSet

FundApps provides automated compliance monitoring services to financial institutions, including some of the world’s largest asset managers, hedge funds, and investment banks. To achieve their mission of making regulatory compliance simple, FundApps builds its services on AWS to cost-effectively handle the scaling demands of a growing business and maximize their ability to invest in innovation, while meeting carbon emission reduction objectives. 

“Babelfish for Amazon Aurora PostgreSQL-Compatible Edition has enabled us to modernize our databases to utilize Amazon Aurora Serverless v2 without having to make significant changes to our application. We used the open-source Babelfish Compass tool to generate a compatibility assessment report, which identified 90% of our SQL commands as compatible with Aurora PostgreSQL. The remaining commands were addressed with simple workarounds leading to a complete migration within weeks. With Babelfish, we were able to avoid rewriting large portions of the application, accelerating time to delivery and allowing the team to focus their time on new product innovation instead of the migration. We chose Aurora Serverless v2 to manage background services, which have huge spikes in demand and long periods of relative inactivity. Aurora Serverless v2 allows us to scale to meet peak demand when required without having to massively over-provision. This allows us to achieve better overall utilisation, lower costs, and a smaller carbon footprint. Overall, the migration from self-managed MS SQL Server to Aurora PostgreSQL has reduced our database costs by over 60%, and we no longer need to undertake a majority of the traditional, undifferentiated maintenance work associated with relational databases. This means our engineers have more time to invest in building valuable new products."

Toby O'Rourke, CTO - FundApps

How to get started

Babelfish for Aurora PostgreSQL is available for Amazon Aurora PostgreSQL-Compatible Edition. Read the documentation, and start with just a few clicks in the Amazon Aurora Management Console.

Learn more about the features of Amazon Aurora

Visit the features page