dataset_info:
- config_name: C
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
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- config_name: CSharp
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
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download_size: 1232015539
dataset_size: 2392066248
- config_name: Cpp
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
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download_size: 1632803797
dataset_size: 3167426435
- config_name: Go
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
- name: detected_licenses_right
large_list: large_string
- name: license_type_right
dtype: large_string
splits:
- name: train
num_bytes: 433053889
num_examples: 1917163
download_size: 179388495
dataset_size: 433053889
- config_name: Java
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
num_bytes: 10292427437
num_examples: 44990158
download_size: 5291667797
dataset_size: 10292427437
- config_name: JavaScript
features:
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dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
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dtype: large_string
- name: length_bytes
dtype: int64
- name: score
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- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
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dataset_size: 2654326008
- config_name: Markdown
features:
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dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
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num_examples: 20687077
download_size: 2058772192
dataset_size: 4268378053
- config_name: PHP
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
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num_examples: 9914497
download_size: 983498806
dataset_size: 1985843762
- config_name: Python
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
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num_examples: 25286019
download_size: 2500795086
dataset_size: 4947575770
- config_name: Ruby
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
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num_examples: 2976874
download_size: 284535771
dataset_size: 592832039
- config_name: Rust
features:
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dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
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num_examples: 1135379
download_size: 103158397
dataset_size: 227434676
- config_name: SQL
features:
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dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
num_bytes: 505669712
num_examples: 2504412
download_size: 261176608
dataset_size: 505669712
- config_name: Shell
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
num_bytes: 811611733
num_examples: 4133547
download_size: 394872047
dataset_size: 811611733
- config_name: Swift
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
num_bytes: 529873695
num_examples: 2454309
download_size: 257883733
dataset_size: 529873695
- config_name: TypeScript
features:
- name: blob_id
dtype: large_string
- name: language
dtype: large_string
- name: repo_name
dtype: large_string
- name: path
dtype: large_string
- name: src_encoding
dtype: large_string
- name: length_bytes
dtype: int64
- name: score
dtype: float64
- name: int_score
dtype: int64
- name: detected_licenses
large_list: large_string
- name: license_type
dtype: large_string
splits:
- name: train
num_bytes: 904736029
num_examples: 4290356
download_size: 425942502
dataset_size: 904736029
configs:
- config_name: C
data_files:
- split: train
path: C/train-*
- config_name: CSharp
data_files:
- split: train
path: CSharp/train-*
- config_name: Cpp
data_files:
- split: train
path: Cpp/train-*
- config_name: Go
data_files:
- split: train
path: Go/train-*
- config_name: Java
data_files:
- split: train
path: Java/train-*
- config_name: JavaScript
data_files:
- split: train
path: JavaScript/train-*
- config_name: Markdown
data_files:
- split: train
path: Markdown/train-*
- config_name: PHP
data_files:
- split: train
path: PHP/train-*
- config_name: Python
data_files:
- split: train
path: Python/train-*
- config_name: Ruby
data_files:
- split: train
path: Ruby/train-*
- config_name: Rust
data_files:
- split: train
path: Rust/train-*
- config_name: SQL
data_files:
- split: train
path: SQL/train-*
- config_name: Shell
data_files:
- split: train
path: Shell/train-*
- config_name: Swift
data_files:
- split: train
path: Swift/train-*
- config_name: TypeScript
data_files:
- split: train
path: TypeScript/train-*
💻 Stack-Edu
Stack-Edu is a 125B token dataset of educational code filtered from The Stack v2, precisely the curated training corpus of StarCoder2 models denoted StarCoder2Data. It is intended for Language Models training.
This dataset was curated using a classifier-based filtering strategy, inspired by 📚 FineWeb-Edu, to retain only the highest-quality educational programming content.
Stack-Edu shows consistent improvement over StarCoder2data on all the programming languages on MultiPL-E benchmark.

Downloading the data
This dataset only contains the SWHIDs to download the code files and not the content of the files itself. The contents can be downloaded from Software Heritage's S3 bucket to ensure data compliance. Please refer to the-stack-v2 for the data license.
When running on a 16-core AWS us-east-1
instance, this script takes ~6 hours to download the files:
import boto3
import gzip
from datasets import load_dataset
from botocore.exceptions import ClientError
num_proc = 16
s3 = boto3.client('s3')
bucket_name = "softwareheritage"
def download_contents(blob_id):
key = f"content/{blob_id}"
try:
obj = s3.get_object(Bucket=bucket_name, Key=key)
with gzip.GzipFile(fileobj=obj['Body']) as fin:
content = fin.read().decode("utf-8", errors="ignore")
return {"text": content, "download_success": True}
except ClientError as e:
if e.response['Error']['Code'] == 'NoSuchKey':
print(f"File not found: {key}")
return {"text": "", "download_success": False}
else:
raise
# For Python
ds = load_dataset("HuggingFaceTB/stack-edu", "Python", split="train", num_proc=num_proc)
ds = ds.map(download_contents, input_columns="blob_id", num_proc=num_proc)
# Filter out failed downloads
ds = ds.filter(lambda x: x['download_success'])
# Optionally, print the first example to verify the data
print(ds[0])
Details
The table below shows the number of tokens in each programming language using SmolLM2 tokenizer.
Language | Stack-Edu (B tokens) |
---|---|
Python | 21.8 |
Cpp | 16.0 |
Markdown | 14.0 |
C | 11.1 |
JavaScript | 11.1 |
Java | 42.1 |
SQL | 9.62 |
PHP | 9.07 |
C-Sharp | 8.87 |
TypeScript | 3.03 |
Shell | 3.13 |
Swift | 1.83 |
Go | 1.80 |
Rust | 1.75 |
Ruby | 1.61 |
Dataset curation
To build Stack-Edu, we:
- Selected 15 largest programming languages from StarCoder2Data
- Trained 15 language-specific classifiers, using StarEncoder model on synthetic annotations generated by Llama3-70B-Instruct. The classifiers for each language are available in this collection.
- Applied a filtering threshold of 3 (out of 5) to retain highly educational content, except for Java, which performed best at threshold 2.
Citation Information
@misc{allal2025smollm2smolgoesbig,
title={SmolLM2: When Smol Goes Big -- Data-Centric Training of a Small Language Model},
author={Loubna Ben Allal and Anton Lozhkov and Elie Bakouch and Gabriel Martín Blázquez and Guilherme Penedo and Lewis Tunstall and Andrés Marafioti and Hynek Kydlíček and Agustín Piqueres Lajarín and Vaibhav Srivastav and Joshua Lochner and Caleb Fahlgren and Xuan-Son Nguyen and Clémentine Fourrier and Ben Burtenshaw and Hugo Larcher and Haojun Zhao and Cyril Zakka and Mathieu Morlon and Colin Raffel and Leandro von Werra and Thomas Wolf},
year={2025},
eprint={2502.02737},
archivePrefix={arXiv},
primaryClass={cs.CL},
url={https://arxiv.org/abs/2502.02737},
}