Overview | NeMo Curator

Load text data from ArXiv, Common Crawl, Wikipedia, and custom sources using Curator.

Curator provides a task-centric pipeline for downloading and processing large-scale public text datasets. It runs on Ray and converts raw formats like Common Crawl’s .warc.gz into JSONL.

How it Works

Curator uses a 4-step pipeline pattern where data flows through stages as tasks. Each step uses a ProcessingStage that transforms tasks according to Curator’s pipeline-based architecture .

Data sources provide composite stages that combine these steps into complete download-and-extract pipelines, producing DocumentBatch tasks for further processing.

Python

from nemo_curator.core.client import RayClient
from nemo_curator.pipeline import Pipeline
from nemo_curator.stages.text.download import CommonCrawlDownloadExtractStage
from nemo_curator.stages.text.io.writer import JsonlWriter
# Initialize Ray client
ray_client = RayClient()
ray_client.start()
# Create a pipeline for downloading Common Crawl data
pipeline = Pipeline(
    name="common_crawl_download",
    description="Download and process Common Crawl web archives"
)
# Add data loading stage
cc_stage = CommonCrawlDownloadExtractStage(
    start_snapshot="2020-50",
    end_snapshot="2020-50",
    download_dir="/tmp/cc_downloads",
    crawl_type="main",
    url_limit=10  # Limit for testing
)
pipeline.add_stage(cc_stage)
# Add writer stage to save as JSONL
writer = JsonlWriter(path="/output/folder")
pipeline.add_stage(writer)
# Execute pipeline
results = pipeline.run()
# Stop Ray client
ray_client.stop()

Data Sources & File Formats

Load data from public datasets and custom data sources using Curator stages.

Read Existing Data

Read existing JSONL and Parquet datasets using Curator’s reader stages jsonl parquet

Common Crawl

Download and extract web archive data from Common Crawl web-data warc html-extraction

Wikipedia

Download and extract Wikipedia articles from Wikipedia dumps articles multilingual xml-dumps

Custom Data Sources

Implement a download and extract pipeline for a custom data source jsonl parquet file-partitioning