Seq

New blog post! A first look at interactive metrics debugging with Seq: datalust.co/blog/seq-met...

The Seq Events screen showing the search expression @Elapsed > 1m.

Tip of the day: sleuthing for slow spans? Combine the @Elapsed built-in with duration expressions and 💥!

January update! datalust.co/blog/jan-eng...

Seq's "What's New?" page has been cumulative since 2020.1.

If you've skipped a release or two, it's a fantastic way to catch up quickly on anything you might have missed 🙂

datalust.co/docs/whats-new

Attendees and presenter in front of a slide titled "Column Oriented Database Internals"

This year we've been in the lucky intersection of features most requested by Seq users, and deeply interesting new tech to design and build.

Heading into 2026 we have a lot to unpack! @liammclennan.bsky.social started with an overview of column stores at @dddbrisbane.bsky.social this month.

Photograph of a busy lecture theater at DDD Brisbane with the presenter gesturing towards overhead slide projection.

The Seq team rounded out 2025 at DDD Adelaide and then DDD Brisbane a month later, both fantastic community-oriented conferences.

Here's Ashley Mannix sharing his experiences shepherding Seq's high-performance #rustlang codebase through back-to-back years of rapid growth.

December Engineering Update: datalust.co/blog/decembe...

At DDD Adelaide 2025 Ashley Mannix will be presenting Industrial Strength Testing for Complex Software

Have you ever thought about having unit tests for your unit tests? 🤔 If so, decent chance your testing isn't catching the bugs you need and is just slowing you down ⏱️ @Ashley Mannix at #DDDAdelaide 2025 shows how to test complex software, challenging what a test is 🧪

Hey that's @liammclennan.bsky.social from @datalust.co speaking at @dddadelaide.bsky.social !

Head over to dddadelaide.com to find out more and buy your ticket before they're all gone. Less than two weeks to go.

What are we working on, now? 👀 datalust.co/blog/what-ar...

👏 A big thank you to Seq for coming on board as a Silver Sponsor for DDD Brisbane 2025!

Community events like DDD Brisbane wouldn’t be possible without the support of sponsors who believe in building and strengthening the local developer community.

Huge thanks to @datalust.co, makers of Seq, for continuing to support DDD events. One of only two tech companies that came to the table for our crazy outback experiment. 🙇🙇🙇 Check out Seq at datalust.co

A screenshot of the archived datalust/seq-forwarder repository on GitHub.

Seq Forwarder has moved!

Seq's own handy little store-and-forward ingestion proxy has been rewritten as the `seqcli forwarder` command group:

github.com/datalust/seq...

The original Seq Forwarder repository has been archived, but past releases will remain available there.

Release v3.1.0 · datalust/superpower #140 - target .NET 6 (@KodrAus) #143 - remove Gitter link (@liammclennan) #144 - remove unnecessary zero-length array allocation (@sq735) #149 - fix divide operator in example parser (@randomC0der)...

Superpower 3.1.0 is a maintenance release with updated TFMs, index/range support on TextSpan, and a new Text() combinator for character parsers:

github.com/datalust/sup...

Seq 2025.2 Release TL;DR: Seq 2025.2 is ready on datalust.co and as datalust/seq in your Docker container registry of choice. A number of improvements were in-flight during the recent Seq 2025.1 release, but came in ...

Seq 2025.2 🎉

blog.datalust.co/seq-2025-2-r...

If you automate Seq deployments in your organization: we've tightened up initialization of new instances, so be sure to read the release notes this time around! ☺️

datalust/seq-tickets Issues, design discussions and feature roadmap for the Seq log server - datalust/seq-tickets

Seq 2025.2 is on its way later today!

This patch includes a few changes that missed the cut-off for inclusion in 2025.1; you can check out what's coming in: github.com/datalust/seq...

Analyzing the distribution of elapsed time and other telemetry metrics Telemetry data often includes numeric values that change over time. This is roughly the definition of an observability 'metric'. It is difficult to infer anything useful by looking at the values of a...

Analyzing the distribution of elapsed time and other telemetry metrics: a primer on averages, percentiles, histograms and heatmaps 🔥

blog.datalust.co/analyzing-th...

The Seq command palette, with "ran" typed in the filter box. The list shows the Custom Range, From Now, Next Range, Previous Range, and To Now shortcuts.

Today's tiny quality-of-life improvement:

If you regularly use the "From now" date range option, grab the latest 2025.1 patch and try Ctrl+Space N 💡

github.com/datalust/seq...

Work Sharing in Seq Clusters We've reviewed leader election and replication in Seq clusters. While these are tricky to get right, and involve nontrivial code, they're dwarfed in complexity by work sharing, which is the basis of S...

Work Sharing in Seq Clusters ✨

blog.datalust.co/work-sharing...

The Seq 2025.1 Events screen, in the "classic" light theme.

Fans of the "classic" light theme, we hear you! ❤️

The latest 2025.1 build brings this back; update, jump into your user preferences, and select "Classic Light" from the theme drop-down 😊

The nifty color palette we adopted here is based on Matteo Niccoli's perceptual rainbow palette, mycartablog.com/2013/02/21/p...

Introducing Heatmaps TL;DR: Heatmaps are a great way to visualize timing data over time. The canonical visualization of two dimensional data is the bar chart. The following screenshot shows a count of events at each logg...

Introducing heatmaps: Seq now implements this popular visualization for three-dimensional data sets 😎

blog.datalust.co/introducing-...

Data Replication in Seq Clusters Now that we've seen how Seq clusters coordinate the leader and follower roles, let's look one layer further down the stack. Log events and traces reach the cluster nodes via HTTP, and internally thes...

Data Replication in Seq Clusters - a new post on our engineering blog:

blog.datalust.co/data-replica...

What's new in seqcli? It's been a while since we posted an update on Seq's hard-working command-line client, seqcli. The 2025.1 build has just been released, but I'll include some favorites here from the 2024.x series as ...

What's new in `seqcli`?

blog.datalust.co/whats-new-in...

2025.1.14099 Milestone · datalust/seq-tickets Issues, design discussions and feature roadmap for the Seq log server - 2025.1.14099 Milestone · datalust/seq-tickets

And one more tiny one today, fixing a glitch in infinite scrolling under Chromium browsers: github.com/datalust/seq...

2025.1 Patch 1 Milestone · datalust/seq-tickets Issues, design discussions and feature roadmap for the Seq log server - 2025.1 Patch 1 Milestone · datalust/seq-tickets

We've just pushed a tiny 2025.1 patch that fixes indexing on single-core machines/containers 😅

Multi-core boxes are unaffected and can ignore this one.

github.com/datalust/seq...

Self-hosting's "moment" is set to be a long one.

We saw the privacy advantages a decade ago, and the momentum is only getting stronger.

The components responsible for tracking node state and orchestrating transitions. A consensus module interacts with the external cluster state database, feeding triggers into the node state machine. Simultaneously, a clock component fires triggers in the state machine too. The state machine sends commands to a command queue, which is observed by a command queue monitor. The command dispatcher pulls commands from the queue, and orchestrates the storage engine and application components.

A peek into the delicate machinery that adapts a running Seq node to its role in the cluster: blog.datalust.co/leader-elect...

Leader Election in Seq Clusters We spent the past 12 months making Seq HA-capable and able to scale work out across multiple nodes. This post is the first of three that dig into how clustering is implemented. It's not so much about ...

The first of a short series digging into how Seq 2025.1 implements HA and scale-out:

blog.datalust.co/leader-elect...

The Seq Events screen, showing the command palette dialog as an overlay. The dialog comprises a search box and a list of matching commands. The search box has been filled with the word "signal", and the command list shows matches including "Add to Signal", "Clear All", "Exclude", "Save", and "Signals", each with help text. Beside the matching command names are the shortcut key sequences for each command, for example Add to Signal is Ctrl Space, A.

Ctrl-K, or Cmd-K on macOS, puts a stack of Seq features in reach without picking up a mouse ✨

This is a Seq update not to miss! Check all of the details at blog.datalust.co/announcing-s...