# projectnessie/nessie

Nessie: Transactional Catalog for Data Lakes with Git-like semantics

Repository: https://github.com/projectnessie/nessie
Canonical: https://ross.abutalabs.com/products/nessie
Homepage: https://projectnessie.org
Language: Java
License: Apache-2.0
License Family: permissive
Topics: data, spark, java, iceberg, aws-lambda, git
Last push: 2026-08-26T11:09:41+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 95, longevity 100
- inputs: {"age_days": 2337, "days_push": 7, "days_rel": 33, "gap_med": 7, "n_releases_24m": 54}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1497, forks 193 (observed 2026-08-28T04:04:53.871507+00:00)

## What it is
Project Nessie is a transactional catalog for data lakes that provides Git-like branching, tagging, and cross-table transactions for Apache Iceberg tables. It is deployed as a server (Docker, Helm, or standalone JAR) exposing the Iceberg REST API and a native REST API, with a CLI/REPL and GC tooling.

## Use cases
- add git-like branching and tagging to a data lake
- run isolated staging and dev environments on the same lakehouse data
- perform atomic multi-table commits across Iceberg tables
- track and roll back bad batch jobs in Spark or Trino pipelines
- implement garbage collection for expired Iceberg data files
- serve an Iceberg REST catalog for multiple query engines

## When to choose
- you use Apache Iceberg and want version control, isolation, and cross-table transactions over your catalog
- you need reproducible data states, tags, and branches for data engineering workflows
- you want a self-hosted catalog deployable via Docker or Kubernetes

## When to avoid
- you use Delta Lake or Apache Hudi rather than Iceberg
- you only need a simple single-version catalog without branching or MVCC
- you want a fully managed cloud catalog service

## Facets
- artifact type: service
- maturity: active
- function: database, version-control, api-framework, cli
- domain: big-data, databases, analytics, developer-tools
- platform: self-hosted, jvm, python, cli
- tags: data-lake, apache-iceberg, catalog, git-like-semantics, spark, trino, dremio, multi-version-concurrency, garbage-collection, data-engineering, docker, kubernetes

## Member repositories
- projectnessie/nessie (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:53.871507+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:33:09.912478+00:00, confidence not recorded.
  - readme: https://github.com/projectnessie/nessie (fetched 2026-08-28T04:04:53.871507+00:00, sha 0ad86cae6707)
  - homepage: https://projectnessie.org (fetched 2026-08-29T11:38:27.682345+00:00, sha df078dd53b86)
  - site_page: https://projectnessie.org/guides/about (fetched 2026-08-29T11:38:27.689617+00:00, sha dc8cca772b48)
  - site_page: https://projectnessie.org/nessie-latest (fetched 2026-08-29T11:38:27.686801+00:00, sha 56377066b669)
  - site_page: https://projectnessie.org/releases (fetched 2026-08-29T11:38:27.692912+00:00, sha 27ff16b73dbd)
  - site_page: https://projectnessie.org/releases-0.69 (fetched 2026-08-29T11:38:27.697419+00:00, sha 6609ffa9f8b8)
  - site_page: https://projectnessie.org/releases-0.49 (fetched 2026-08-29T11:38:27.700650+00:00, sha 55910a47e41b)
- Data as of 2026-08-30T08:39:29.467469+00:00.