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Datasets:
Titlehhhh
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captchaocr-dataset

Tasks:
Image-to-Text
Modalities:
Image
Tabular
Text
Formats:
parquet
Languages:
English
Russian
Size:
100K - 1M
Tags:
captcha
ocr
minecraft
anti-bot
Synthetic
parquet
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metadata 
license: other
license_name: mixed-per-plugin-licences
license_link: https://huggingface.co/datasets/Titlehhhh/captchaocr-dataset/blob/main/LICENSE
pretty_name: CaptchaOCR — Minecraft anti-bot captchas
task_categories:
  - image-to-text
language:
  - en
  - ru
tags:
  - captcha
  - ocr
  - minecraft
  - anti-bot
  - synthetic
  - parquet
  - image
size_categories: 100K<n<1M
configs:
  - config_name: default
    data_files: data/*.parquet
Six captcha styles from Minecraft anti-bot plugins: map codes, a chat code, Cyrillic symbols and a web captcha

CaptchaOCR — Minecraft anti-bot captchas as training data

Minecraft anti-bot captchas, re-rendered by this project's Java 21 generators and packed one image per Parquet row: image, answer, drawn text and answer band.

samples types plugins size format task license

What's inside

  • 20 captcha types from 13 upstream names — 6 pixel-faithful ports, 10 clean-room reimplementations, 4 reconstructions with no upstream plugin.
  • 200,000 images, 10,000 per type, one Parquet row each, with every label field from labels.jsonl in the same row.
  • 9 Parquet shards, 1.9 GiB — 30–248 MiB each, no loading script, no remote code.
  • roi in 12 of 20 types — 119,984 answer bands; the other 80,016 rows need the whole frame.

Gallery

Six examples of these types, answer under each image.

Krypton map captcha with a five-letter code
Krypton/map — Wu43b		 mapcha map captcha with a four-letter code
mapcha/map — ly8r		 XProtect chat code captcha
XProtect/code — 5dqnZ9
LimboFilter Cyrillic symbol captcha
LimboFilter/symbols — БЬ5		 Reconstructed web captcha, 150 by 90 pixels
GalleryCaptcha/ru-web — cVejm		 CaptchaVerifyZ map captcha in capital letters
CaptchaVerifyZ/map — AYKZB

Quickstart 

import io
from datasets import load_dataset
from PIL import Image

ds = load_dataset("Titlehhhh/captchaocr-dataset", split="train")
row = ds[0]
image = Image.open(io.BytesIO(row["image"])); print(row["answer"], row["roi"])
Filter one type, or read a shard with pyarrow 
ds = load_dataset("Titlehhhh/captchaocr-dataset", split="train")
subset = ds.filter(lambda row: row["type_id"] == "out/haq/mapcha/map")

import pyarrow.parquet as pq

table = pq.read_table("data/train-00000-of-00009.parquet",
                      columns=["type_id", "answer"])

train-00000-of-00009.parquet is the first of 9 shards; the row order is deterministic (tree, type, labels.jsonl order).

Fields

column type meaning
image binary raw PNG bytes; decode with PIL.Image.open(io.BytesIO(...))
file string file name inside the type directory (001.png …)
type_id string type path, e.g. out/Archy-X/Krypton/map
plugin string upstream plugin, e.g. haq/mapcha
captcha string captcha style inside the plugin, e.g. map
answer string what the player types into the answer field
text string, nullable what is drawn on the image
prompt string, nullable task text the plugin shows
roi list<int32>, nullable answer band [x, y, w, h]
width int32 PNG width in pixels
height int32 PNG height in pixels
source string upstream class and method that produced the style
tree string out (Latin) or out_ru (Cyrillic)

text is what is drawn; answer is what the player types. They differ in 3 types, where a solver step converts one to the other — train a recogniser on text, evaluate a solver on answer. roi is the answer band; when the band does not fit the frame, roi is null, so pass the whole image and never crop those rows.

Types

20 types from 13 upstream names. roi rows count rows with the band present; text ≠ answer counts rows where the drawn string differs from the typed answer.

All 20 types
type_id plugin captcha samples roi rows text ≠ answer mode license
out/Archy-X/Krypton/map Archy-X/Krypton map 10,000 10,000 0 clean-room No licence — all rights reserved
out/InstantlyMoist/Captcha/textcaptcha InstantlyMoist/Captcha textcaptcha 10,000 0 0 faithful MIT
out/JSH32/Minecaptcha/map JSH32/Minecaptcha map 10,000 10,000 0 faithful MIT
out/LagBug/XProtect/code LagBug/XProtect code 10,000 0 0 faithful MIT
out/LagBug/XProtect/map LagBug/XProtect map 10,000 0 0 faithful MIT
out/haq/mapcha/map haq/mapcha map 10,000 9,984 0 faithful MIT
out/irootdev/AnBot/captcha irootdev/AnBot captcha 10,000 0 0 clean-room GPL-3.0
out/jonesdevelopment/sonar/complex jonesdevelopment/sonar complex 10,000 0 0 clean-room GPL-3.0
out/jonesdevelopment/sonar/legacy jonesdevelopment/sonar legacy 10,000 0 0 clean-room GPL-3.0
out/jonesdevelopment/sonar/standard jonesdevelopment/sonar standard 10,000 0 0 clean-room GPL-3.0
out/just-captcha/ProstoCaptcha/map just-captcha/ProstoCaptcha map 10,000 10,000 0 faithful MIT
out/ringoame196-s-mcPlugin/ReproductionCAPTCHA/map ringoame196-s-mcPlugin/ReproductionCAPTCHA map 10,000 10,000 0 clean-room No licence file — all rights reserved
out_ru/BotFilter/map BotFilter map 10,000 0 0 clean-room BSD-2-Clause, no commercial hosting
out_ru/CaptchaVerifyZ/map CaptchaVerifyZ map 10,000 10,000 0 clean-room All rights reserved (Modrinth)
out_ru/GalleryCaptcha/ru-numberword GalleryCaptcha ru-numberword 10,000 10,000 10,000 reconstructed Not established (see source)
out_ru/GalleryCaptcha/ru-numberword-caption GalleryCaptcha ru-numberword-caption 10,000 10,000 10,000 reconstructed Not established (see source)
out_ru/GalleryCaptcha/ru-symbols GalleryCaptcha ru-symbols 10,000 10,000 0 reconstructed Not established (see source)
out_ru/GalleryCaptcha/ru-web GalleryCaptcha ru-web 10,000 10,000 0 reconstructed Not established (see source)
out_ru/LimboFilter/map LimboFilter map 10,000 10,000 10,000 clean-room AGPL-3.0
out_ru/LimboFilter/symbols LimboFilter symbols 10,000 10,000 0 clean-room AGPL-3.0

This snapshot holds 20 of the 21 types in the generator tree. out_ru/LimboFilter/digits was rendered after the snapshot and is not published here.

License

Each row carries the license of the upstream plugin it came from, so the dataset as a whole is mixed (license_name: mixed-per-plugin-licences). Several upstream licenses forbid commercial hosting or reserve all rights, so check the table before you ship anything. Full text: LICENSE.

Licenses by upstream plugin
plugin types samples license mode
Archy-X/Krypton 1 10,000 No licence — all rights reserved clean-room
BotFilter 1 10,000 BSD-2-Clause, no commercial hosting clean-room
CaptchaVerifyZ 1 10,000 All rights reserved (Modrinth) clean-room
GalleryCaptcha 4 40,000 Not established (see source) reconstructed
InstantlyMoist/Captcha 1 10,000 MIT faithful
JSH32/Minecaptcha 1 10,000 MIT faithful
LagBug/XProtect 2 20,000 MIT faithful
LimboFilter 2 20,000 AGPL-3.0 clean-room
haq/mapcha 1 10,000 MIT faithful
irootdev/AnBot 1 10,000 GPL-3.0 clean-room
jonesdevelopment/sonar 3 30,000 GPL-3.0 clean-room
just-captcha/ProstoCaptcha 1 10,000 MIT faithful
ringoame196-s-mcPlugin/ReproductionCAPTCHA 1 10,000 No licence file — all rights reserved clean-room

mode says how close the pixels are to the upstream plugin: faithful is a port of the upstream drawing code, clean-room is a reimplementation from the algorithm, reconstructed means no upstream plugin was available.

Provenance

  • Every image is a re-render by the Java 21 generators in this repository, not a screenshot and not a copy.
  • 6 types are pixel-faithful ports, 10 are clean-room reimplementations, 4 are reconstructed from reference screenshots.
  • The generators are not seeded: this is one random render (2026-10-24). The labels and the generator code are the reproducible part.
  • The upstream reference screenshots that guided the reconstructions are not published; they are other people's images.
  • No image, page or answer from a third-party commercial service is included.

Limitations

  • Synthetic images: fonts, noise and layout follow the plugin algorithms, not a live server, so expect a gap on real screenshots.
  • 8 types have no roi; there the answer band is not in the frame, so feed the whole image.
  • 3 types put a solver step between the drawn string and the answer; OCR alone does not solve them.
  • Other anti-bot plugins are not represented: the snapshot stops at the types listed above.