Seal Report: a .NET reporting framework that also runs your ETL tasks
Database Reporting Tool and Tasks (.Net)
At a glance
- What is it?
- Seal Report combines a report designer, a web report server, a scheduler and a task engine in one C# codebase under the MIT licence. It is a good fit if your data already lives in a database you control; it is a poor fit if you want a hosted BI product with no Windows or .NET footprint.
- Who is it for?
- Adopt Seal Report if your team writes C# or SQL, your data sits in a relational database or MongoDB, and you want report design, scheduling and ETL under one MIT-licensed roof rather than three subscriptions. Do not adopt it if you need a SaaS BI tool with no local runtime, or if you cannot deploy and patch .NET 10 and WebView2 on the machines that will design reports.
- Can I use it commercially?
- Yes. MIT is a permissive licence: you can use, modify and sell software built on it, as long as you keep its copyright and licence notices.
- Is it still maintained?
- Yes. The repository last received commits 1 day ago.
- What is it written in?
- Mainly C#, according to GitHub's language statistics.
Answers come from the project's GitHub data, last synced on September 15, 2026, and from our analysis. They are not legal advice.
DEEP OPEN-SOURCE ANALYSIS
The gap Seal Report fills: reporting and batch work in one .NET codebase
Most teams that need scheduled reports end up stitching together three things: a query layer, a rendering layer, and a job runner. Seal Report presents itself as a single framework covering all three. The README describes it as a framework for producing reports from any database or NoSQL source and for performing complex tasks such as ETL and batch operations, written entirely in C# for Microsoft .NET and released under the MIT License. The intended audience is not a business analyst clicking through a hosted dashboard. It is a developer or a data team that already owns a .NET stack and wants report output, scheduling and data movement in the same project. The repository topics list confirms the breadth: report-generator, reporting-engine, task-scheduler, etl, dashboards, chart, pdf, excel. That breadth is the pitch and also the reason to read the system requirements carefully before you start.
How the engine builds queries: dynamic SQL, LINQ, and pivot tables
The mechanism that separates Seal Report from a template renderer is its query layer. The README states that you can use your own SQL, or let the Seal engine build the SQL used to query your database dynamically. That second mode means the report definition describes columns, restrictions and aggregations, and the engine translates them into the statement it sends to the database. The practical consequence is that a designer can add a restriction without hand-editing SQL, and the generated statement changes accordingly. Alongside this, the LINQ path lets you join and query sources that do not share a query language: SQL, Excel, XML, OLAP cubes and HTTP JSON endpoints. That is the more interesting capability. A report that pulls a JSON feed and joins it to a SQL table is a normal LINQ operation here, and doing the same in a pure SQL tool would mean staging the JSON into a table first. Pivot tables are native, with drag-and-drop elements placed directly into a cross tab, and charts are defined by picking series rather than writing chart configuration. The README claims chart series can be defined in two mouse clicks and lists ChartJS, ECharts, Plotly, ScottPlot and Gauge as supported libraries. Treat the click count as marketing and the library list as the useful part.
Output rendering: Razor for HTML, ClosedXML for Excel, QuestPDF for PDF
Rendering is where the dependency choices become visible. HTML output is produced through the Razor engine, which means a report template is a Razor view and you get Bootstrap layout, responsiveness, table sorting and filtering for free if the template uses them. This is a real design decision, not a checkbox: it means the people customising report presentation need Razor syntax, not a proprietary template language. Excel output goes through ClosedXML and PDF through QuestPDF, both named in the README. XML, JSON, text and CSV are also available. The README notes that third-party components carry their own licences, listed in THIRD-PARTY-NOTICES.md, and singles out QuestPDF in particular if your own code calls its APIs directly. That sentence matters more than it looks. QuestPDF has its own licence terms independent of Seal Report's MIT licence, so a commercial deployment that reaches into QuestPDF directly is governed by those terms, not by the MIT grant on Seal Report itself.
Getting it running: install, connect, design, publish
The README's Quick Start is four steps. Install by downloading the latest setup from GitHub Releases. Connect by declaring a data source in the Server Manager, choosing from OLE DB, ODBC, MS SQL Server, Oracle, MySQL, SQLite, PostgreSQL, MongoDB, Excel or CSV. Design in the Report Designer by dragging elements, adding restrictions and choosing charts, or by handing the job to the AI assistant. Publish by deploying the Web Report Server on Windows or Linux and scheduling report outputs. The system requirements are the part to read before downloading. For use you need .NET 10.0, specifically the Microsoft Windows Desktop Runtime 10, plus the driver for whichever database you connect to. The Report Designer needs Microsoft Edge WebView2. The Web Report Server needs Internet Information Server with the ASP.NET Core Runtime 10 Hosting Bundle on Windows, or the ASP.NET Core Runtime on Linux. Development targets Visual Studio 2026. None of these are exotic, but they are all recent, and the WebView2 requirement in particular means the designer is a desktop Windows application, not a browser page.
The AI agent layer and what it actually does
Recent releases lean on AI features, and the README is specific enough to judge them. You chat with role-based agents to design reports, analyse data, manage data sources, schedule executions or administer the server. The provider is yours: OpenAI, Azure OpenAI, Anthropic or Ollama, including local models. AI tasks can also be embedded inside reports, which is a different proposition from a chat sidebar. An embedded AI task means a report execution can call a model as part of producing its output, for classification or summarisation of rows, for example. Two things the README does not state: which model versions are supported, and what data leaves your environment when a task runs against a hosted provider. The Ollama option is the answer for anyone who cannot send data out, but the documentation supplied here does not describe how agent permissions are scoped, so treat role-based agents as a feature to test against your own data before you point one at a production source.
Scheduling, tasks and the delivery targets
The scheduler covers more ground than a cron wrapper. According to the README, report executions can be scheduled to generate results in folders, on FTP or SFTP servers, or in SharePoint document libraries, or be sent by email through SMTP, SendGrid or MS Graph. It integrates with the Windows Task Scheduler or runs as a service. The task engine is separate from report scheduling and handles ETL and batch work: data load, Excel load, file download from FTP or SFTP, zip, backup, data processing, and triggering procedures from external assemblies. That last item is the escape hatch. If a step is not covered by the built-in task types, you write it in C# and call it. The cost of this design is that the scheduler and the task engine are Windows-centric in their integration story, since the Windows Task Scheduler is named explicitly, even though the Web Report Server itself runs on Linux.
Where Seal Report is the wrong tool
The clearest limitation is the runtime footprint. This is not a hosted product. Every environment that designs or serves reports needs .NET 10, and designers additionally need Edge WebView2 on Windows. A team that wants analysts to build reports from a browser on any machine will find that constraint harder to accept than the feature list suggests. Second, the reporting model assumes you can reach the data. Dynamic SQL generation is powerful precisely because it pushes work to the database, which means the database has to be reachable and the account has to have the right permissions. Third, the AI features depend on an external provider unless you run Ollama, and the supplied material does not document how agent actions are audited or restricted. Fourth, the project is maintained by a single company, Ariacom, with support offered through a paid subscription. MIT licensing means the code cannot be taken away from you, but it does not mean someone else will answer your questions. If your reporting needs are a handful of static PDFs generated once a month, the setup cost here is not justified.
Alternatives and the actual difference in approach
The obvious comparison is Microsoft's own stack: Power BI for dashboards and SQL Server Reporting Services for paginated reports. The difference is architectural. Those products assume a Microsoft platform subscription and a service to host them, and their extension model is configuration and embedded code rather than a C# codebase you can read. Seal Report is a self-hosted .NET application whose source you have, with LINQ joining sources that SSRS cannot join without staging. A second comparison is Metabase or Superset, which are web-first and expect the browser to be the design surface. Seal Report puts the designer on the desktop and the server on IIS or Linux. If browser-only design is a hard requirement, Metabase is the closer fit and Seal Report is the wrong choice. If you need ETL tasks and report scheduling in the same process, the web-first tools generally do not offer that, and Seal Report does.
Maintenance, upgrade cost and licence boundaries
The release history shows a steady cadence: v8.4 in October 2025, v8.5 in April 2026, and v10.0.1 in July 2026, with the repository last pushed in September 2026. That jump from 8.5 to 10.0.1 in roughly three months is worth asking about before you pin a version, because the supplied material does not explain what changed. The README claims low total cost of ownership and minimal ongoing maintenance, which is a claim rather than a measurement. What can be verified is the dependency surface: .NET 10, WebView2, database drivers, ClosedXML, QuestPDF, and whichever chart libraries you enable. Each of those moves on its own schedule. On licensing, Seal Report itself is MIT, which permits commercial use and modification. That grant does not extend to the third-party components, and the README explicitly points to THIRD-PARTY-NOTICES.md for them. This is not legal advice; if you redistribute Seal Report inside a commercial product, read that file and the QuestPDF terms yourself before shipping.
Editorial conclusion
Adopt Seal Report if your team writes C# or SQL, your data sits in a relational database or MongoDB, and you want report design, scheduling and ETL under one MIT-licensed roof rather than three subscriptions. Do not adopt it if you need a SaaS BI tool with no local runtime, or if you cannot deploy and patch .NET 10 and WebView2 on the machines that will design reports. Before committing, verify two things: that your target database has a driver in the supported list, and that the QuestPDF licensing terms in THIRD-PARTY-NOTICES.md suit your distribution model, especially if your own code calls QuestPDF APIs directly.
Community notes