Updated November 8, 2026 · Thinwork, the team behind dbSlice. dbSlice is our product; the other tools are described from their own sites.
Quick answer
- A free, one-time load scripted by your team: pgloader.
- You are moving to AWS and want ongoing replication of changes: AWS DMS.
- A free desktop tool for an occasional table copy: DBeaver Community.
- Stored procedures, functions and views converted to PostgreSQL: a code conversion tool such as SQLines SQL Converter, or a conversion workstream. Pair it with a data tool.
- The data moved, then kept in sync until cutover, and both sides compared key by key before the switch, from a Windows app or the command line: dbSlice.
Who should pick what
| If you… | Pick | Why |
|---|---|---|
| Want free and open source, and are fine with the command line | pgloader | Reads SQL Server and loads PostgreSQL with tables, indexes and foreign keys, and reports rows and time per table (checked Nov 2, 2026) |
| Are migrating into AWS and need changes replicated while you test | AWS DMS | Runs in the AWS Cloud, does one-time migrations or ongoing replication; schema conversion is a separate service (DMS Schema Conversion or AWS SCT); pay as you go, by the hour (checked Oct 30, 2026) |
| Already use DBeaver and need an occasional copy | DBeaver Community | The free edition has a data transfer wizard that copies tables between databases. DBeaver lists data migration, table data comparison and a task scheduler in its Enterprise (US$ 255/year) and Ultimate (US$ 510/year) editions (checked Nov 8, 2026). DBeaver vs dbSlice → |
| Want a dedicated tool per database pair | DBConvert | One product per database pair converts and syncs it: DBConvert for MSSQL & PostgreSQL from US$ 199; DBConvert Studio, for all its database types with scheduling and trigger-based sync, from US$ 699 (checked Nov 8, 2026) |
| Need many source types, including files and older databases, with a large budget | Full Convert | Plans from US$ 999 a year (Pro); perpetual from US$ 1,999 (checked Nov 8, 2026) |
| Need SQL code converted as well as data moved | SQLines | One perpetual license covers SQLines Data and SQLines SQL Converter: US$ 495 (checked Nov 8, 2026) |
| Need the target kept in sync for weeks or months and proof that both sides match | dbSlice | Initial load, then Upsert, New rows only, Update existing only or incremental by column, in batch, on demand or on a schedule; key-by-key compare with the list of divergent keys saved to a file; from US$ 89.99 perpetual (launch price) |
Microsoft's SQL Server Migration Assistant (SSMA) works the other way: it moves Access, Db2, MySQL, Oracle and SAP ASE databases into SQL Server and Azure SQL. It does not target PostgreSQL (checked Oct 30, 2026).
Side by side
| pgloader | AWS DMS | DBeaver | DBConvert | Full Convert | SQLines | dbSlice | |
|---|---|---|---|---|---|---|---|
| Where it runs | Command line | AWS Cloud | Desktop app | Desktop app | Desktop app | Desktop and command line | Windows app and CLI; Linux edition in Docker |
| Converts procedures and views | Not covered on this page | Separate service | Not covered on this page | Views; procedures, functions and triggers stay in the source | Not covered on this page | Yes (SQL Converter) | No |
| Keeps the target in sync after the first load | Re-run the load | Ongoing replication | Scheduled tasks in paid editions | Sync in the pair product; trigger-based sync and scheduling in Studio | Replication (Pro) | Not covered on this page | Upsert, new-only, update-only, incremental by column (batch, on demand or scheduled) |
| Compares source and target data | Report with rows, bytes and time per table | Data validation | Table data comparison in paid editions | Not covered on this page | Table comparison (Pro) | Not covered on this page | Key by key, full list of divergent keys |
| Entry price | Free | By the hour | Free (Community) | US$ 199 per pair | US$ 999/year | US$ 495 | US$ 89.99 perpetual (launch price) |
| Checked on | Nov 2 | Oct 30 | Nov 8 | Nov 8 | Nov 8 | Nov 8 | Nov 8 |
"Not covered on this page" means we did not find it on the vendor's site when we checked. It does not mean the tool cannot do it.
The honest con about dbSlice
- dbSlice moves data. It does not convert stored procedures, triggers or views. It shows the PostgreSQL DDL for a missing table instead of creating it on its own.
- It runs batch jobs, not real-time replication. Incremental runs do not see rows deleted at the source, so run Compare or a reload before the switch.
- It is a Windows app with a command line. The Linux edition runs in Docker on your own infrastructure.
If any of those is a deal-breaker, pick one of the tools above, or pair one of them with dbSlice.
How teams combine them
- Code: convert procedures and views with a code conversion tool.
- Data: run the initial load with dbSlice, then keep PostgreSQL in sync every night while the old SQL Server application is still running.
- Before cutover: run Compare key by key and re-sync only the divergent keys. Then switch.
See the full walkthrough: data migration from SQL Server to PostgreSQL, with a sync until cutover.
Moving from MySQL instead? See the MySQL to PostgreSQL tools.
Moving to MySQL instead? See the SQL Server to MySQL tools.
In one dbSlice license: migrate · keep in sync on a schedule · CLI jobs · compare key by key · masking with keys and foreign keys preserved · synthetic test data for DEV and QA
FAQ
What is the best free tool to migrate SQL Server to PostgreSQL?
For a one-time load, pgloader, which is free and open source. DBeaver Community, also free, copies tables between databases from its data transfer wizard.
Which tool keeps SQL Server and PostgreSQL in sync until cutover?
AWS DMS replicates changes when you migrate into AWS. dbSlice re-runs Upsert or incremental syncs on a schedule, from a Windows app, the command line or its Linux edition, on your own machines.
Do I need a separate tool for stored procedures?
Usually yes. Data tools move tables; procedures, functions and views need a conversion tool or a manual rewrite.
Can I try dbSlice before buying?
Yes. The free version on the Microsoft Store connects, browses data, compares structures and exports to CSV. Writing to a target needs a Desktop or Server license, with a 14-day money-back guarantee.
Planning a system replacement and need help designing the coexistence? Thinwork can run the project with you.