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OpenRefine

OpenRefine is a free, open-source data cleaning and transformation tool designed to help users clean, normalize, and reconcile messy data. It originated as Google Refine and was released as OpenRefine in 2012 after Google ceased active development. The software runs as a desktop application that starts a local server and provides a web-based user interface, typically accessed from a browser on the local machine. Because it operates locally, users can work on sensitive data without uploading it to external services.

OpenRefine focuses on data refinement and transformation tasks. Key features include filtering, faceting to explore subsets

For data integration and export, OpenRefine supports a variety of input and output formats, including CSV, TSV,

of
data,
and
clustering
to
identify
and
merge
duplicate
records.
Transformations
and
data
edits
are
performed
with
General
Refine
Expression
Language
(GREL),
built-in
expressions,
and
pattern-based
operations,
enabling
complex
data
cleaning
workflows.
The
project-based
approach
tracks
changes
and
provides
undo/redo
capabilities,
supporting
reproducible
data
preparation.
Excel,
JSON,
and
XML,
and
it
can
connect
to
reconciliation
services
to
match
entities
against
external
data
sources.
Through
its
extensible
architecture
and
community-driven
development,
it
offers
extensions
and
integrations
that
expand
connectivity
and
capabilities.
OpenRefine
is
widely
used
by
data
journalists,
researchers,
librarians,
and
data
scientists
for
tasks
such
as
deduplication,
normalization,
enrichment,
and
preparing
datasets
for
analysis
or
publication.