qsv is a blazing-fast, composable data-wrangling toolkit for CSV, TSV, SSV, Excel, JSON/JSONL, Parquet and more. 80 commands across five binary variants, and a single binary that fits in your toolbox.

Latest release: 24.0.0 — the "Evidence Act" release — ~160 commits since 23.0.1, and the theme is evidence: the plumbing that lets agencies build policy on data that is open, machine-readable and described in a public inventory. The inventory first: profile now emits canonical DCAT-US v3 that passes data.gov's own validator, and --validate asserts formats and is tested against GSA's 23 conformance fixtures. Then the evidence itself: one new command, writestat, writes CSV back out as SPSS, Stata or SAS transport, and readstat --dictionary writes a JSON Schema data dictionary from the file's own labels and missing-value codes — so a SAS/Stata/SPSS file round-trips with its metadata, and readstat no longer drops user-defined missing values silently. moarstats grows from 56 to 73 measures, each checked against scipy (Jarque-Bera, the Bimodality Coefficient and kurtosis are corrected, so their values change). Every command now describes itself (--help --format json|md), frequency is 1.5–2× faster, the un-indexed count regression is fixed, and new Linux ARM64 musl and Windows ARM64 GNU prebuilts round out the platforms. See the full changelog.

Welcome! This wiki is the workflow + discoverability layer for qsv. Use it to learn how the commands fit together and find recipes for real-world tasks. For per-command flag references, follow the deep-links into /docs/help/ — that's the canonical reference.

Then jump to Getting Started for a hands-on tutorial, or Why qsv? for the elevator pitch.

qsv documentation lives on several surfaces. Each has a different job:

Surface	Job
README.md	Project overview, command catalog with legend, install options, feature flags
/docs/ (canonical reference)	The source of truth: PERFORMANCE.md, BENCHMARKS.md, ENVIRONMENT_VARIABLES.md, STATS_DEFINITIONS.md, Validate.md, Fetch.md, Describegpt.md, INTERPRETERS.md, plus the whirlwind tour
/docs/help/	Per-command help — flags, arguments, examples
This wiki	Workflow & discoverability: getting started, cookbook recipes, command-reference category guides, tuning, integrations, troubleshooting
100.dathere.com	Interactive lessons & exercises (WIP)
Discussions	Q&A, FAQ, announcements, ideas
	LLM-generated Wiki that crawls the codebase once a week, that you can chat with!

Every wiki page has a Tier badge — Beginner, Intermediate, or Advanced. See the Tier Legend for what each tier assumes.

Installation · Getting Started · Why qsv? · Command Reference (index) · Cookbook · Troubleshooting · FAQ · Glossary · External Resources · qsv pro

Binary Variants · Transform & Reshape · Aggregation & Statistics · Joins & Set Ops · Validation & Schema · Conversion & I/O · Geospatial · HTTP & Web · Indexing, Compression & Diff · AI & Documentation · Comparison vs others · Integrations · US Census Integration · Claude Cowork Plugin · MCP Server

SQL & Polars · Scripting (Luau / Python) · Performance Tuning · Environment Variables · Stats Cache & Caching · Lookup Tables · Contributing to the Wiki

Examples in this wiki reach for a small set of datasets repeatedly, so you build mental models:

• wcp.csv — World Cities Population, 2.7M rows / 124 MB. Used in Getting Started and many command-reference examples. Available in files/wcp.zip.
• NYC 311 Service Requests — public dataset, available as a 1M-row sample and a full 16 GB / 27M-row export. Used in Validation, SQL & Polars, Geographic Enrichment, Larger-than-RAM.
• Boston 311 — small (100 rows) and in many compression formats (.csv, .gz, .zst, .parquet). Used in Clean & Normalize and conversion demos.
• Allegheny County property sales — mid-size, already indexed. Used in Build a Data Pipeline and Stats → Insights.
• NOAA GHCN-Daily — weather time-series, fetched via qsv fetch. Used in Fetch & Cache and Multi-table Joins (asof joins).
• GitHub stargazers — qsv's own stars, fetched via qsv fetch. Used in HTTP & Web demos.

No install required: visit qsv.dathere.com to try qsv against a sample CSV right now.

• "Have we achieved ACI?" series: 1 · 2 · 3
• NYC SOD 2026 · csv,conf,v9 · PyCon US 2025 · csv,conf,v8 · NYC SOD 2022
• Full list: External Resources

These pages predate the wiki rewrite. Their content has been integrated into the new structure but the originals are kept for backwards-compatibility with external links:

• Cookbook (legacy) — original recipes; new Cookbook expands them
• qsv cheat sheet — pre-rewrite infographic & quick reference (WIP)
• Luau Development — folded into Scripting (Luau / Python)
• Luau Helper Functions Examples — referenced from Scripting (Luau / Python)
• describegpt model notes — folded into AI & Documentation
• xsv 0.13.0 stats vs qsv 1.0.0 stats — referenced from Comparison vs others

This wiki is itself a git repo at https://github.com/dathere/qsv.wiki.git. See Contributing to the Wiki for clone/edit/push instructions and the verification checklist.