Yes—SQL Server 2025 Express is free to install and use at a company, including for commercial, lightweight production workloads; selecting Mixed Mode authentication does not change the edition or introduce a SQL Server license charge.^1^
Use the Express (SQLEXPR) package rather than Developer or Evaluation edition. Microsoft describes SQL Server 2025 Express as a free edition for desktop, web, and small-server applications.^2^ Your deployment remains subject to the SQL Server 2025 license terms.^3^
Important Express limits
Before using it in production, confirm that the workload fits these per-instance limits:
- Database Engine compute: lesser of one socket or four cores
- Buffer-pool memory: 1,410 MB
- Maximum relational database size: 50 GB per database
- Some production features are unavailable, including Always On availability groups, failover cluster instances, log shipping, backup compression, and Database Mail.^1^
The 50-GB database limit is new for SQL Server 2025 Express; Express with Advanced Services was discontinued because its former features are now included in the unified Express edition.^4^
Edition cautions
- Developer editions: Free, but licensed only for development and testing—not production.
- Evaluation edition: Expires after 180 days.
- Express edition: The appropriate free edition for a small production workload.^1^
Mixed Mode permits both Windows authentication and SQL Server authentication. It does not remove the Express limits above. For formal compliance approval specific to your organization or redistribution scenario, have your licensing or legal team review the published Microsoft License Terms.
References
- Editions and supported features of SQL Server 2025
- Microsoft® SQL Server® 2025 Express
- Microsoft License Terms
- What's new in SQL Server 2025