Data tools

Interactive data systems

Small systems built around validation, explicit data limits, and reproducible exports—not ad-hoc scratch files in place of a delivery contract. Streamlit powers the interactive session; the repo still owns tests, config, and deployment. These mirror the storefront’s prep and KPI lanes before premium ML engagements.

Key architecture notes (show)

Schema checks, row caps, and structured reject paths so bad inputs fail loudly instead of polluting downstream numbers.
Pytest-backed pipelines and pinned assumptions where they matter; exports match what ran on the server.
Optional LLM steps only see metrics and aggregates—never row-level free text—so scope stays reviewable.

Portfolio leads with batch- and API-shaped ML implementations; Data tools demonstrates the same habits for interactive spreadsheets and CSV workflows—constraints, receipts, repeatable exports. Contracts and scope appear on Services.

GitHub repositories — supplementary context; cards open expanded notes on Work and still expose repository and demo in each footer.

Apps in this track

Data cleaning toolkit

Streamlit
pandas
pytest
Parquet / JSON
Docker

Upstream prerequisite, not a side utility: downstream models and dashboards ingest the same reviewed tables—multi-format inputs become auditable CSV/Parquet/JSON plus HTML step log and before/after views, capped near 100K rows; rules cover bad formats, duplicates, skewed categories, optional outliers, plus bundled samples for dry runs.

JSON flattening stays one level by design. Pairs with EDA on this page (profile vs fix). Deploy mirrors the repository limits and validation logic.

GitHubLive demo

EDA report generator

Streamlit
pandas
pytest
Jinja2
WeasyPrint

Read-only dossier you can archive or forward—no cell edits: capped sampling with sheet picker, full column intelligence, correlations, histograms, and warnings, rendered to HTML from memory with optional PDF when WeasyPrint is available. Single-column junk files fail fast.

Natural companion to the cleaning toolkit (inspect here, mutate there). PDF failures surface in UI while HTML export still succeeds. docs/DEPLOY_VPS.md covers self-host parity with the repo.

GitHubLive demo

AI-assisted data analysis

Streamlit
Plotly
Aggregates-only AI
HTML report

Exploration plus written explanation—not KPI tracking: one business CSV yields profile, a fixed chart pack, rule-based quality hints, and optional OpenAI narrative built only from aggregates (never raw rows), bundled as one HTML story for readers who need context, not a metric wall.

UTF-8 CSV with config-driven caps; empty analysis still finishes and explains missing API keys. Suited to marketing/sales/customer-behaviour tables.

GitHubLive demo

KPI dashboard implementation example

Streamlit
Sales & marketing CSV
Mapping presets
Optional OpenAI

An interactive implementation reference—not a SaaS subscription: preset mappings and hard row gates produce KPI cards, trends, breakdowns, optional deltas, and a rule-first “what changed?” so stakeholders see how a scoped Sheets or BI dashboard engagement would behave.

Commercial delivery stays a written milestone—your workbook or BI artefact with your KPI dictionary and refresh rules. This public instance showcases interaction patterns only; snapshots export as ZIP for handoff discussion. No product login, SLA, or multi-tenant support—narrow MVP mirrors how fixed-scope KPI packages are constrained.

GitHubLive demo

Forecasting app

Streamlit
Holt-Winters
Plotly
Rolling backtest

Univariate demand curves with honest baselines—not neural nets: resampled Holt-Winters by day/week/month only when seasonality is supportable; Plotly band with MAPE/MAE against naive; warnings and fallback reasons stay visible for operators validating the forecast.

Sidebar-triggered run exports forecast CSV plus summary JSON. Bundled sample series and CLI smoke live in-repo; promo or holiday regressors stay out of scope with explicit naive fallback when fit is weak.

GitHubLive demo

Each card links to repository and live demo on a vahdetlabs.com subdomain—implementation references tied to storefront services, not subscribed products.