The best Seq yet is here… Announcing 3.1!

Today our cadence of monthly releases continues with the general availability of Seq 3.1, the latest update to our log management platform for modern .NET apps.

Seq is an HTTP-based log server with superpowers: given structured data from libraries like Serilog, Semantic Logging or the .NET Core platform, Seq provides effortless log filtering, correlation and querying without the need for log parsing or regular expressions.

How does it do this? Seq embraces the simple idea that the best way to extract structured data from application logs is not to throw it away in the first place. Watch the Pluralsight course or the ASP.NET Monsters on Channel 9 to learn how this is possible.

There’s no better way to demonstrate the power of this approach than to see Seq 3.1 in action. Here’s a typical application logging statement:

Log.Information("Payment submission completed in {Elapsed} ms",

Notice the extended format string. This message template associates the name Elapsed with the timing value from a Stopwatch.

Written to the console, this event looks like a simple text string. But, when we view these events in Seq, the number embedded in the message is recognized:

Structured Event Data

...we can filter on it using the full range of numeric operators:

Numeric Operators

...and in Seq 3.1, we can easily view changes in the value over time:


For the same up-front effort as it would take to produce a traditional text log with log4net, a modern structured logger + Seq delivers a lot more opportunities to really dig in and understand the behavior of an application.


You can see an example of Seq 3.1’s timeseries view above. SQL queries can now also produce beautiful doughnut and bar charts directly from log data.


It’s possible to go from a vanilla-looking log statement to charting percentiles, without a single regular expression or custom script in sight :-)

The great thing about this is it’s not limited to performance metrics. Mechanical “APM” instrumentation knows nothing about the data that’s meaningful to you. With structured logs you can gain full visibility into dollar values, item counts, temperatures, interest rates, … ice cream flavors … whatever has significance in your business domain, and get first class monitoring and diagnostics on that information.

Charting is supported over simple projections, groupings, and all of the aggregate operators introduced in Seq 3.

Integrated Windows authentication

For teams enjoying Seq’s Active Directory authentication support, Seq 3.1 makes logging in even easier by supporting integrated NTLM challenge-response authentication.

Integrated Windows Auth

This means supporting browsers can log the current Windows user into Seq directly, in most cases without a login prompt or password request.

Updated signal editor, filter bar and timeline

The timeline and filter bar have been redesigned in 3.1 to feel smoother and more consistent, using a layout that now serves both the stream view and tabular SQL views equally.

Filter and query history in the filter bar drop-down is saved between sessions, and individual queries or filters can be pinned to keep them handy indefinitely.

Saved Queries

Over in the signal bar, individual filters can be edited in-place by clicking on them, instead of requiring a round-trip of removal/modification/re-adding.

Installing and upgrading

Seq 3.1 is a quick in-place upgrade for existing 2.0-3.1 installations. .NET 4.5.2 or better is required as of this version - make sure you upgrade .NET before upgrading Seq if your Seq server is running an unsupported .NET version.

Download the installer now.

This version no longer supports upgrading directly from the 1.x series of releases, which are now two generations behind the current version.

If you currently use Seq 1.x, please upgrade to Seq 3.0 before installing the new release.

If you have any questions or concerns about upgrading, please reach out to - we'll make sure the process is smooth and quick.

Release notes for Seq 3.1.16

There are many goodies in 3.1 we couldn't fit into this announcement. Check out the milestone in the issue tracker for a more comprehensive overview.

Since Seq 3.0:

  • Charting/evolution of numerical values over time (#299)
  • Implement automatic login via NTLM challenge when AD authentication is enabled (#383)
  • Unified layout for stream/query views (#403)
  • Saved SQL queries (#378)
  • Add some commonly-used aggregates to the quick-filter list (#404)
  • Tabbing should work between date range from/to inputs (#402)
  • Aggregate to list available property names (#395)
  • Filter history is lost when navigating out of the 'events' screen (#394)
  • List installed instances (#393)
  • Sign EXE binaries to improve installation experience (#392)
  • Make it easier to find/install popular apps (#391)
  • In-place filter editing (#390)
  • Event property names that are too long cause the list to become misaligned (#388)
  • Add TimeOfDay() and TimeSpan() built-in functions (#387)
  • Results of ToIsoString() and ToHexString() cannot be matched using regex (#386)
  • Show a status message when disk space is low, and when (license) maintenance has expired (#385)
  • Server status message z-order too low when shown over dash charts (#384)
  • "Move to signal" disabled for SQL queries, but can still be clicked (#382)
  • Allow setting listen URL and storage path during installation (#372)
  • Seq installer not checking .NET framework version (#371)
  • Quoted syntax for non-C# property names (#359)
  • After upgrading to v2+, browser cache from v1+ is not refreshed (#289)
  • Dashboard doesn't remember the last selected time frame for charts (#250)
  • Disable manual trigger of Seq app (#157)

Nicholas Blumhardt

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