DataLens

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What DataLens is

DataLens is an open-source tool for profiling CSV files in a browser and turning them into interactive reports. It automatically detects numeric, categorical, and datetime columns, and accepts multiple CSV files through drag and drop or clipboard paste. Its eight chart types are bar, line, pie, donut, scatter, radar, histogram, and box plot. It calculates Pearson correlations and presents them in a heatmap, while text insights surface outliers, trends, top-k segments, and cross-correlations.

The assistant can use Ollama, OpenRouter, Groq, or any OpenAI-compatible endpoint. The maker says CSV data stays in the browser and AI requests go directly from the browser tab to the configured provider. DataLens runs offline without installation or a backend, either in a browser or locally from its HTML file or an HTTP server. CSV uploads are described as supporting files up to approximately 50 MB. Users can export a PDF report or download filtered CSV data. The interface is available in French and English, and the project is released under the MIT License. The maker describes it as an auto-report generator for analysts who would rather not start a notebook.

Who it suits

DataLens suits analysts who want to profile CSV data and create a report without starting a notebook. It also fits people who want offline, local use and browser-based analysis with optional AI provider connections.

What it does well

Profiles columns and detects numeric, categorical, and datetime data automatically.
Provides eight chart types and Pearson correlation heatmaps.
Surfaces outliers, trends, top-k segments, and cross-correlations as text.
Runs offline without installation or a backend.
Exports PDF reports and filtered CSV files.
Open source under the MIT License, with French and English interface options.

What to know first

CSV uploads are described up to approximately 50 MB.
It does not connect to SQL databases.

Limits

CSV uploads are described as supporting files up to approximately 50 MB. SQL database connections are not supported.

Getting started

Open the DataLens website in a browser, or run its HTML file locally or through an HTTP server.
Import CSV files by drag and drop or paste data from the clipboard.
Review the detected column types, charts, correlation heatmap, and text insights.
Optionally connect the assistant to Ollama, OpenRouter, Groq, or an OpenAI-compatible endpoint.
Export a PDF report or download filtered CSV data.

Verdict

Pick DataLens for free, open-source CSV analysis with interactive charts, automatic insights, and local or offline use. Look elsewhere if your workflow depends on direct SQL connections or CSV files beyond its described approximate upload size.

Questions

Is DataLens free?

Yes. It is listed as free and open source under the MIT License.

Which file types can it import?

DataLens imports CSV files, including multiple files through drag and drop or data pasted from the clipboard.

Can it connect to SQL databases?

No. SQL connections are listed as unsupported.

Can I use DataLens offline?

Yes. The maker says it runs offline without installation or a backend, and can be opened as a local HTML file or served locally.

Which AI providers can the assistant use?

It supports Ollama, OpenRouter, Groq, and any OpenAI-compatible endpoint.

What can I export?

You can export a PDF report and download filtered CSV data.

Facts from DataLens's own pages

AI integrations: The assistant supports Ollama, OpenRouter, Groq, and any OpenAI-compatible endpoint. · bran9910.github.io, 9 Oct 2026
Analysis: It provides Pearson correlation heatmaps and automatic insights about outliers, trends, segments, and correlations. · bran9910.github.io, 9 Oct 2026
Automatic insights: It surfaces outliers, trends, top-k segments, and cross-correlations as text. · bran9910.github.io, 9 Oct 2026
Charts: It provides eight chart types: bar, line, pie, donut, scatter, radar, histogram, and box plot. · bran9910.github.io, 9 Oct 2026
CSV import: It supports drag-and-drop multi-file CSV import, clipboard paste, and automatic detection of numeric, categorical, and datetime columns. · bran9910.github.io, 9 Oct 2026
Data handling: The site says CSV data stays in the browser and AI requests go directly from the browser tab to the configured provider. · bran9910.github.io, 9 Oct 2026
Deployment: The GitHub README says the app can be opened in a browser or run locally from its HTML file or an HTTP server. · github.com, 9 Oct 2026
Export: It offers one-click PDF report export and filtered CSV download. · bran9910.github.io, 9 Oct 2026
Exports: Users can export a PDF report and download filtered CSV data. · bran9910.github.io, 9 Oct 2026
File size limit: The maker describes CSV support up to approximately 50 MB. · bran9910.github.io, 9 Oct 2026
Import limit: The site describes CSV uploads up to approximately 50 MB. · bran9910.github.io, 9 Oct 2026
Intended audience: The maker describes DataLens as an auto-report generator for analysts who would rather not start a notebook. · bran9910.github.io, 9 Oct 2026
Interface: The GitHub README says the interface is available in French and English. · github.com, 9 Oct 2026
Interface languages: The GitHub project page states that the interface is available in French and English. · github.com, 9 Oct 2026
License: DataLens is open source under the MIT License. · github.com, 9 Oct 2026
Local use: The app can be opened as a local HTML file or served from a local HTTP server. · github.com, 9 Oct 2026
Offline use: The site says DataLens runs offline and requires no installation or backend. · bran9910.github.io, 9 Oct 2026
Purpose: DataLens reads CSV files in the browser, profiles columns, and creates an interactive report. · bran9910.github.io, 9 Oct 2026
Statistics: It calculates Pearson correlations and displays them in a heatmap. · bran9910.github.io, 9 Oct 2026

Where DataLens stands on Freedom251

AI Data Analysis Tools#6 of 27