Structured logs for .NET apps

Seq is the fastest way for development teams to carry the benefits of structured logging from development through to production.

Modern structured logging bridges the gap between human-friendly text logs, and machine-readable formats like JSON. Using event data from libraries such as Serilog, ASP.NET Core, and Node.js, Seq makes centralized logs easy to read, and easy to filter and correlate, without fragile log parsing.

Seq has already solved several visibility problems
— Arri Rucker, City Corridor

Developers in thousands of companies rely on Seq every day. Hear what our customers have to say about us in insurance, retail, and health care.

Works with the tools you love

Seq collects data over HTTP, while your applications use the best available structured logging APIs for your platform. The simple Windows installer, and plug-ins from NuGet or NPM, make getting started quick and friction-free.

Seq is a web application hosted on your infrastructure, so you retain complete control over your own data.

Rich Event Data — Structured logging adds context to errors and application events. Quickly zoom-in to find related events by filtering on properties, or use the same technique to exclude noise and see only what is relevant to a line of exploration.

Support for message templates seamlessly fuses text and structured data when used with libraries supporting them.

Rich Event Data

Intuitive Filtering — Use SQL expression syntax or familiar C#/JavaScript-style operators including ==, !=, <, <= and so-on. Built-in functions include fundamentals like StartsWith(), EndsWith(), IndexOf() and Contains().

Full-text search and /regular expressions/ are supported, too: just type free text into the filter bar and Seq will find it in log messages and stack traces.

Filter Syntax

Save and Share Filters — Signals are saved filters that can be applied with one click. Easily view the intersection of two or more filters, like Errors and Production to view only the logs you’re interested in.

Signals and queries are shared across your team so everyone can tune in.


Integrate and Notify — Tail events matching a filter in real-time, or use a pre-built integration to send events to an issue tracker, Slack or HipChat.

Extend Seq to react to events using C#, or modify one of the many examples available on GitHub.

A comprehensive HTTP API client makes it easy to query data from your own applications.

Seq Apps

Analyze and Chart with SQL — SQL queries with grouping, aggregation and time-slicing let you dig deeper into system behavior and performance.

Property-aware CSV export makes it easy to take analysis further with Excel and industry-standard business intelligence tools.

SQL Queries

Our customers