GLiNER2: Unified Schema-Based Information Extraction

Extract entities, classify text, parse structured data, and extract relations—all in one efficient model.

GLiNER2 unifies Named Entity Recognition, Text Classification, Structured Data Extraction, and Relation Extraction into a single 205M parameter model. It provides efficient CPU-based inference without requiring complex pipelines or external API dependencies.

✨ Why GLiNER2?

🎯 One Model, Four Tasks: Entities, classification, structured data, and relations in a single forward pass
💻 CPU First: Lightning-fast inference on standard hardware—no GPU required
🛡️ Privacy: 100% local processing, zero external dependencies

🚀 Installation & Quick Start

pip install gliner2

from gliner2 import GLiNER2

# Load model once, use everywhere
extractor = GLiNER2.from_pretrained("fastino/gliner2-base-v1")

# Extract entities in one line
text = "Apple CEO Tim Cook announced iPhone 15 in Cupertino yesterday."
result = extractor.extract_entities(text, ["company", "person", "product", "location"])

print(result)
# {'entities': {'company': ['Apple'], 'person': ['Tim Cook'], 'product': ['iPhone 15'], 'location': ['Cupertino']}}

🌐 API Access: GLiNER XL 1B

Our biggest and most powerful model—GLiNER XL 1B—is available exclusively via API. No GPU required, no model downloads, just instant access to state-of-the-art extraction. Get your API key at gliner.pioneer.ai.

from gliner2 import GLiNER2

# Access GLiNER XL 1B via API
extractor = GLiNER2.from_api()  # Uses PIONEER_API_KEY env variable

result = extractor.extract_entities(
    "OpenAI CEO Sam Altman announced GPT-5 at their San Francisco headquarters.",
    ["company", "person", "product", "location"]
)
# {'entities': {'company': ['OpenAI'], 'person': ['Sam Altman'], 'product': ['GPT-5'], 'location': ['San Francisco']}}

📦 Available Models

Model	Parameters	Description	Use Case
`fastino/gliner2-base-v1`	205M	base size	Extraction / classification
`fastino/gliner2-large-v1`	340M	large size	Extraction / classification

The models are available on Hugging Face.

📚 Documentation & Tutorials

Comprehensive guides for all GLiNER2 features:

Core Features

Text Classification - Single and multi-label classification with confidence scores
Entity Extraction - Named entity recognition with descriptions and spans
Structured Data Extraction - Parse complex JSON structures from text
Combined Schemas - Multi-task extraction in a single pass
Regex Validators - Filter and validate extracted spans
Relation Extraction - Extract relationships between entities
API Access - Use GLiNER2 via cloud API

Training & Customization

Training Data Format - Complete guide to preparing training data
Model Training - Train custom models for your domain
LoRA Adapters - Parameter-efficient fine-tuning
Adapter Switching - Switch between domain adapters

🎯 Core Capabilities

1. Entity Extraction

Extract named entities with optional descriptions for precision:

# Basic entity extraction
entities = extractor.extract_entities(
    "Patient received 400mg ibuprofen for severe headache at 2 PM.",
    ["medication", "dosage", "symptom", "time"]
)
# Output: {'entities': {'medication': ['ibuprofen'], 'dosage': ['400mg'], 'symptom': ['severe headache'], 'time': ['2 PM']}}

# Enhanced with descriptions for medical accuracy
entities = extractor.extract_entities(
    "Patient received 400mg ibuprofen for severe headache at 2 PM.",
    {
        "medication": "Names of drugs, medications, or pharmaceutical substances",
        "dosage": "Specific amounts like '400mg', '2 tablets', or '5ml'",
        "symptom": "Medical symptoms, conditions, or patient complaints",
        "time": "Time references like '2 PM', 'morning', or 'after lunch'"
    }
)
# Same output but with higher accuracy due to context descriptions

# With confidence scores
entities = extractor.extract_entities(
    "Apple Inc. CEO Tim Cook announced iPhone 15 in Cupertino.",
    ["company", "person", "product", "location"],
    include_confidence=True
)
# Output: {
#     'entities': {
#         'company': [{'text': 'Apple Inc.', 'confidence': 0.95}],
#         'person': [{'text': 'Tim Cook', 'confidence': 0.92}],
#         'product': [{'text': 'iPhone 15', 'confidence': 0.88}],
#         'location': [{'text': 'Cupertino', 'confidence': 0.90}]
#     }
# }

# With character positions (spans)
entities = extractor.extract_entities(
    "Apple Inc. CEO Tim Cook announced iPhone 15 in Cupertino.",
    ["company", "person", "product"],
    include_spans=True
)
# Output: {
#     'entities': {
#         'company': [{'text': 'Apple Inc.', 'start': 0, 'end': 9}],
#         'person': [{'text': 'Tim Cook', 'start': 15, 'end': 23}],
#         'product': [{'text': 'iPhone 15', 'start': 35, 'end': 44}]
#     }
# }

# With both confidence and spans
entities = extractor.extract_entities(
    "Apple Inc. CEO Tim Cook announced iPhone 15 in Cupertino.",
    ["company", "person", "product"],
    include_confidence=True,
    include_spans=True
)
# Output: {
#     'entities': {
#         'company': [{'text': 'Apple Inc.', 'confidence': 0.95, 'start': 0, 'end': 9}],
#         'person': [{'text': 'Tim Cook', 'confidence': 0.92, 'start': 15, 'end': 23}],
#         'product': [{'text': 'iPhone 15', 'confidence': 0.88, 'start': 35, 'end': 44}]
#     }
# }

2. Text Classification

Single or multi-label classification with configurable confidence:

# Sentiment analysis
result = extractor.classify_text(
    "This laptop has amazing performance but terrible battery life!",
    {"sentiment": ["positive", "negative", "neutral"]}
)
# Output: {'sentiment': 'negative'}

# Multi-aspect classification
result = extractor.classify_text(
    "Great camera quality, decent performance, but poor battery life.",
    {
        "aspects": {
            "labels": ["camera", "performance", "battery", "display", "price"],
            "multi_label": True,
            "cls_threshold": 0.4
        }
    }
)
# Output: {'aspects': ['camera', 'performance', 'battery']}

# With confidence scores
result = extractor.classify_text(
    "This laptop has amazing performance but terrible battery life!",
    {"sentiment": ["positive", "negative", "neutral"]},
    include_confidence=True
)
# Output: {'sentiment': {'label': 'negative', 'confidence': 0.82}}

# Multi-label with confidence
schema = extractor.create_schema().classification(
    "topics",
    ["technology", "business", "health", "politics", "sports"],
    multi_label=True,
    cls_threshold=0.3
)
text = "Apple announced new health monitoring features in their latest smartwatch, boosting their stock price."
results = extractor.extract(text, schema, include_confidence=True)
# Output: {
#     'topics': [
#         {'label': 'technology', 'confidence': 0.92},
#         {'label': 'business', 'confidence': 0.78},
#         {'label': 'health', 'confidence': 0.65}
#     ]
# }

3. Structured Data Extraction

Parse complex structured information with field-level control:

# Product information extraction
text = "iPhone 15 Pro Max with 256GB storage, A17 Pro chip, priced at $1199. Available in titanium and black colors."

result = extractor.extract_json(
    text,
    {
        "product": [
            "name::str::Full product name and model",
            "storage::str::Storage capacity like 256GB or 1TB", 
            "processor::str::Chip or processor information",
            "price::str::Product price with currency",
            "colors::list::Available color options"
        ]
    }
)
# Output: {
#     'product': [{
#         'name': 'iPhone 15 Pro Max',
#         'storage': '256GB', 
#         'processor': 'A17 Pro chip',
#         'price': '$1199',
#         'colors': ['titanium', 'black']
#     }]
# }

# Multiple structured entities
text = "Apple Inc. headquarters in Cupertino launched iPhone 15 for $999 and MacBook Air for $1299."

result = extractor.extract_json(
    text,
    {
        "company": [
            "name::str::Company name",
            "location::str::Company headquarters or office location"
        ],
        "products": [
            "name::str::Product name and model",
            "price::str::Product retail price"
        ]
    }
)
# Output: {
#     'company': [{'name': 'Apple Inc.', 'location': 'Cupertino'}],
#     'products': [
#         {'name': 'iPhone 15', 'price': '$999'},
#         {'name': 'MacBook Air', 'price': '$1299'}
#     ]
# }

# With confidence scores
result = extractor.extract_json(
    "The MacBook Pro costs $1999 and features M3 chip, 16GB RAM, and 512GB storage.",
    {
        "product": [
            "name::str",
            "price",
            "features"
        ]
    },
    include_confidence=True
)
# Output: {
#     'product': [{
#         'name': {'text': 'MacBook Pro', 'confidence': 0.95},
#         'price': [{'text': '$1999', 'confidence': 0.92}],
#         'features': [
#             {'text': 'M3 chip', 'confidence': 0.88},
#             {'text': '16GB RAM', 'confidence': 0.90},
#             {'text': '512GB storage', 'confidence': 0.87}
#         ]
#     }]
# }

# With character positions (spans)
result = extractor.extract_json(
    "The MacBook Pro costs $1999 and features M3 chip.",
    {
        "product": [
            "name::str",
            "price"
        ]
    },
    include_spans=True
)
# Output: {
#     'product': [{
#         'name': {'text': 'MacBook Pro', 'start': 4, 'end': 15},
#         'price': [{'text': '$1999', 'start': 22, 'end': 27}]
#     }]
# }

# With both confidence and spans
result = extractor.extract_json(
    "The MacBook Pro costs $1999 and features M3 chip, 16GB RAM, and 512GB storage.",
    {
        "product": [
            "name::str",
            "price",
            "features"
        ]
    },
    include_confidence=True,
    include_spans=True
)
# Output: {
#     'product': [{
#         'name': {'text': 'MacBook Pro', 'confidence': 0.95, 'start': 4, 'end': 15},
#         'price': [{'text': '$1999', 'confidence': 0.92, 'start': 22, 'end': 27}],
#         'features': [
#             {'text': 'M3 chip', 'confidence': 0.88, 'start': 32, 'end': 39},
#             {'text': '16GB RAM', 'confidence': 0.90, 'start': 41, 'end': 49},
#             {'text': '512GB storage', 'confidence': 0.87, 'start': 55, 'end': 68}
#         ]
#     }]
# }

4. Relation Extraction

Extract relationships between entities as directional tuples:

# Basic relation extraction
text = "John works for Apple Inc. and lives in San Francisco. Apple Inc. is located in Cupertino."

result = extractor.extract_relations(
    text,
    ["works_for", "lives_in", "located_in"]
)
# Output: {
#     'relation_extraction': {
#         'works_for': [('John', 'Apple Inc.')],
#         'lives_in': [('John', 'San Francisco')],
#         'located_in': [('Apple Inc.', 'Cupertino')]
#     }
# }

# With descriptions for better accuracy
schema = extractor.create_schema().relations({
    "works_for": "Employment relationship where person works at organization",
    "founded": "Founding relationship where person created organization",
    "acquired": "Acquisition relationship where company bought another company",
    "located_in": "Geographic relationship where entity is in a location"
})

text = "Elon Musk founded SpaceX in 2002. SpaceX is located in Hawthorne, California."
results = extractor.extract(text, schema)
# Output: {
#     'relation_extraction': {
#         'founded': [('Elon Musk', 'SpaceX')],
#         'located_in': [('SpaceX', 'Hawthorne, California')]
#     }
# }

# With confidence scores
results = extractor.extract_relations(
    "John works for Apple Inc. and lives in San Francisco.",
    ["works_for", "lives_in"],
    include_confidence=True
)
# Output: {
#     'relation_extraction': {
#         'works_for': [{
#             'head': {'text': 'John', 'confidence': 0.95},
#             'tail': {'text': 'Apple Inc.', 'confidence': 0.92}
#         }],
#         'lives_in': [{
#             'head': {'text': 'John', 'confidence': 0.94},
#             'tail': {'text': 'San Francisco', 'confidence': 0.91}
#         }]
#     }
# }

# With character positions (spans)
results = extractor.extract_relations(
    "John works for Apple Inc. and lives in San Francisco.",
    ["works_for", "lives_in"],
    include_spans=True
)
# Output: {
#     'relation_extraction': {
#         'works_for': [{
#             'head': {'text': 'John', 'start': 0, 'end': 4},
#             'tail': {'text': 'Apple Inc.', 'start': 15, 'end': 25}
#         }],
#         'lives_in': [{
#             'head': {'text': 'John', 'start': 0, 'end': 4},
#             'tail': {'text': 'San Francisco', 'start': 33, 'end': 46}
#         }]
#     }
# }

# With both confidence and spans
results = extractor.extract_relations(
    "John works for Apple Inc. and lives in San Francisco.",
    ["works_for", "lives_in"],
    include_confidence=True,
    include_spans=True
)
# Output: {
#     'relation_extraction': {
#         'works_for': [{
#             'head': {'text': 'John', 'confidence': 0.95, 'start': 0, 'end': 4},
#             'tail': {'text': 'Apple Inc.', 'confidence': 0.92, 'start': 15, 'end': 25}
#         }],
#         'lives_in': [{
#             'head': {'text': 'John', 'confidence': 0.94, 'start': 0, 'end': 4},
#             'tail': {'text': 'San Francisco', 'confidence': 0.91, 'start': 33, 'end': 46}
#         }]
#     }
# }

5. Multi-Task Schema Composition

Combine all extraction types when you need comprehensive analysis:

# Use create_schema() for multi-task scenarios
schema = (extractor.create_schema()
    # Extract key entities
    .entities({
        "person": "Names of people, executives, or individuals",
        "company": "Organization, corporation, or business names", 
        "product": "Products, services, or offerings mentioned"
    })
    
    # Classify the content
    .classification("sentiment", ["positive", "negative", "neutral"])
    .classification("category", ["technology", "business", "finance", "healthcare"])
    
    # Extract relationships
    .relations(["works_for", "founded", "located_in"])
    
    # Extract structured product details
    .structure("product_info")
        .field("name", dtype="str")
        .field("price", dtype="str")
        .field("features", dtype="list")
        .field("availability", dtype="str", choices=["in_stock", "pre_order", "sold_out"])
)

# Comprehensive extraction in one pass
text = "Apple CEO Tim Cook unveiled the revolutionary iPhone 15 Pro for $999. The device features an A17 Pro chip and titanium design. Tim Cook works for Apple, which is located in Cupertino."

results = extractor.extract(text, schema)
# Output: {
#     'entities': {
#         'person': ['Tim Cook'], 
#         'company': ['Apple'], 
#         'product': ['iPhone 15 Pro']
#     },
#     'sentiment': 'positive',
#     'category': 'technology',
#     'relation_extraction': {
#         'works_for': [('Tim Cook', 'Apple')],
#         'located_in': [('Apple', 'Cupertino')]
#     },
#     'product_info': [{
#         'name': 'iPhone 15 Pro',
#         'price': '$999',
#         'features': ['A17 Pro chip', 'titanium design'],
#         'availability': 'in_stock'
#     }]
# }

🏭 Example Usage Scenarios

Financial Document Processing

financial_text = """
Transaction Report: Goldman Sachs processed a $2.5M equity trade for Tesla Inc. 
on March 15, 2024. Commission: $1,250. Status: Completed.
"""

# Extract structured financial data
result = extractor.extract_json(
    financial_text,
    {
        "transaction": [
            "broker::str::Financial institution or brokerage firm",
            "amount::str::Transaction amount with currency",
            "security::str::Stock, bond, or financial instrument",
            "date::str::Transaction date",
            "commission::str::Fees or commission charged", 
            "status::str::Transaction status",
            "type::[equity|bond|option|future|forex]::str::Type of financial instrument"
        ]
    }
)
# Output: {
#     'transaction': [{
#         'broker': 'Goldman Sachs',
#         'amount': '$2.5M', 
#         'security': 'Tesla Inc.',
#         'date': 'March 15, 2024',
#         'commission': '$1,250',
#         'status': 'Completed',
#         'type': 'equity'
#     }]
# }

Healthcare Information Extraction

medical_record = """
Patient: Sarah Johnson, 34, presented with acute chest pain and shortness of breath.
Prescribed: Lisinopril 10mg daily, Metoprolol 25mg twice daily.
Follow-up scheduled for next Tuesday.
"""

result = extractor.extract_json(
    medical_record,
    {
        "patient_info": [
            "name::str::Patient full name",
            "age::str::Patient age",
            "symptoms::list::Reported symptoms or complaints"
        ],
        "prescriptions": [
            "medication::str::Drug or medication name",
            "dosage::str::Dosage amount and frequency",
            "frequency::str::How often to take the medication"
        ]
    }
)
# Output: {
#     'patient_info': [{
#         'name': 'Sarah Johnson',
#         'age': '34',
#         'symptoms': ['acute chest pain', 'shortness of breath']
#     }],
#     'prescriptions': [
#         {'medication': 'Lisinopril', 'dosage': '10mg', 'frequency': 'daily'},
#         {'medication': 'Metoprolol', 'dosage': '25mg', 'frequency': 'twice daily'}
#     ]
# }

Legal Contract Analysis

contract_text = """
Service Agreement between TechCorp LLC and DataSystems Inc., effective January 1, 2024.
Monthly fee: $15,000. Contract term: 24 months with automatic renewal.
Termination clause: 30-day written notice required.
"""

# Multi-task extraction for comprehensive analysis
schema = (extractor.create_schema()
    .entities(["company", "date", "duration", "fee"])
    .classification("contract_type", ["service", "employment", "nda", "partnership"])
    .relations(["signed_by", "involves", "dated"])
    .structure("contract_terms")
        .field("parties", dtype="list")
        .field("effective_date", dtype="str")
        .field("monthly_fee", dtype="str")
        .field("term_length", dtype="str")
        .field("renewal", dtype="str", choices=["automatic", "manual", "none"])
        .field("termination_notice", dtype="str")
)

results = extractor.extract(contract_text, schema)
# Output: {
#     'entities': {
#         'company': ['TechCorp LLC', 'DataSystems Inc.'],
#         'date': ['January 1, 2024'],
#         'duration': ['24 months'],
#         'fee': ['$15,000']
#     },
#     'contract_type': 'service',
#     'relation_extraction': {
#         'involves': [('TechCorp LLC', 'DataSystems Inc.')],
#         'dated': [('Service Agreement', 'January 1, 2024')]
#     },
#     'contract_terms': [{
#         'parties': ['TechCorp LLC', 'DataSystems Inc.'],
#         'effective_date': 'January 1, 2024',
#         'monthly_fee': '$15,000',
#         'term_length': '24 months', 
#         'renewal': 'automatic',
#         'termination_notice': '30-day written notice'
#     }]
# }

Knowledge Graph Construction

# Extract entities and relations for knowledge graph building
text = """
Elon Musk founded SpaceX in 2002. SpaceX is located in Hawthorne, California.
SpaceX acquired Swarm Technologies in 2021. Many engineers work for SpaceX.
"""

schema = (extractor.create_schema()
    .entities(["person", "organization", "location", "date"])
    .relations({
        "founded": "Founding relationship where person created organization",
        "acquired": "Acquisition relationship where company bought another company",
        "located_in": "Geographic relationship where entity is in a location",
        "works_for": "Employment relationship where person works at organization"
    })
)

results = extractor.extract(text, schema)
# Output: {
#     'entities': {
#         'person': ['Elon Musk', 'engineers'],
#         'organization': ['SpaceX', 'Swarm Technologies'],
#         'location': ['Hawthorne, California'],
#         'date': ['2002', '2021']
#     },
#     'relation_extraction': {
#         'founded': [('Elon Musk', 'SpaceX')],
#         'acquired': [('SpaceX', 'Swarm Technologies')],
#         'located_in': [('SpaceX', 'Hawthorne, California')],
#         'works_for': [('engineers', 'SpaceX')]
#     }
# }

⚙️ Advanced Configuration

Custom Confidence Thresholds

# High-precision extraction for critical fields
result = extractor.extract_json(
    text,
    {
        "financial_data": [
            "account_number::str::Bank account number",  # default threshold
            "amount::str::Transaction amount",           # default threshold  
            "routing_number::str::Bank routing number"   # default threshold
        ]
    },
    threshold=0.9  # High confidence for all fields
)

# Per-field thresholds using schema builder (for multi-task scenarios)
schema = (extractor.create_schema()
    .structure("sensitive_data")
        .field("ssn", dtype="str", threshold=0.95)         # Highest precision
        .field("email", dtype="str", threshold=0.8)        # Medium precision  
        .field("phone", dtype="str", threshold=0.7)        # Lower precision
)

Field Types and Constraints

# Structured extraction with choices and types
result = extractor.extract_json(
    "Premium subscription at $99/month with mobile and web access.",
    {
        "subscription": [
            "tier::[basic|premium|enterprise]::str::Subscription level",
            "price::str::Monthly or annual cost",
            "billing::[monthly|annual]::str::Billing frequency", 
            "features::[mobile|web|api|analytics]::list::Included features"
        ]
    }
)
# Output: {
#     'subscription': [{
#         'tier': 'premium',
#         'price': '$99/month', 
#         'billing': 'monthly',
#         'features': ['mobile', 'web']
#     }]
# }

🔍 Regex Validators

Filter extracted spans to ensure they match expected patterns, improving extraction quality and reducing false positives.

from gliner2 import GLiNER2, RegexValidator

extractor = GLiNER2.from_pretrained("fastino/gliner2-base-v1")

# Email validation
email_validator = RegexValidator(r"^[\w\.-]+@[\w\.-]+\.\w+$")
schema = (extractor.create_schema()
    .structure("contact")
        .field("email", dtype="str", validators=[email_validator])
)

text = "Contact: [email protected], not-an-email, [email protected]"
results = extractor.extract(text, schema)
# Output: {'contact': [{'email': '[email protected]'}]}  # Only valid emails

# Phone number validation (US format)
phone_validator = RegexValidator(r"\(\d{3}\)\s\d{3}-\d{4}", mode="partial")
schema = (extractor.create_schema()
    .structure("contact")
        .field("phone", dtype="str", validators=[phone_validator])
)

text = "Call (555) 123-4567 or 5551234567"
results = extractor.extract(text, schema)
# Output: {'contact': [{'phone': '(555) 123-4567'}]}  # Second number filtered out

# URL validation
url_validator = RegexValidator(r"^https?://", mode="partial")
schema = (extractor.create_schema()
    .structure("links")
        .field("url", dtype="list", validators=[url_validator])
)

text = "Visit https://example.com or www.site.com"
results = extractor.extract(text, schema)
# Output: {'links': [{'url': ['https://example.com']}]}  # www.site.com filtered out

# Exclude test data
import re
no_test_validator = RegexValidator(r"^(test|demo|sample)", exclude=True, flags=re.IGNORECASE)
schema = (extractor.create_schema()
    .structure("products")
        .field("name", dtype="list", validators=[no_test_validator])
)

text = "Products: iPhone, Test Phone, Samsung Galaxy"
results = extractor.extract(text, schema)
# Output: {'products': [{'name': ['iPhone', 'Samsung Galaxy']}]}  # Test Phone excluded

# Multiple validators (all must pass)
username_validators = [
    RegexValidator(r"^[a-zA-Z0-9_]+$"),  # Alphanumeric + underscore
    RegexValidator(r"^.{3,20}$"),        # 3-20 characters
    RegexValidator(r"^(?!admin)", exclude=True, flags=re.IGNORECASE)  # No "admin"
]

schema = (extractor.create_schema()
    .structure("user")
        .field("username", dtype="str", validators=username_validators)
)

text = "Users: ab, john_doe, user@domain, admin, valid_user123"
results = extractor.extract(text, schema)
# Output: {'user': [{'username': 'john_doe'}]}  # Only valid usernames

📦 Batch Processing

Process multiple texts efficiently in a single call:

# Batch entity extraction
texts = [
    "Google's Sundar Pichai unveiled Gemini AI in Mountain View.",
    "Microsoft CEO Satya Nadella announced Copilot at Build 2023.",
    "Amazon's Andy Jassy revealed new AWS services in Seattle."
]

results = extractor.batch_extract_entities(
    texts,
    ["company", "person", "product", "location"],
    batch_size=8
)
# Returns list of results, one per input text

# Batch relation extraction
texts = [
    "John works for Microsoft and lives in Seattle.",
    "Sarah founded TechStartup in 2020.",
    "Bob reports to Alice at Google."
]

results = extractor.batch_extract_relations(
    texts,
    ["works_for", "founded", "reports_to", "lives_in"],
    batch_size=8
)
# Returns list of relation extraction results for each text
# All requested relation types appear in each result, even if empty

# Batch with confidence and spans
results = extractor.batch_extract_entities(
    texts,
    ["company", "person"],
    include_confidence=True,
    include_spans=True,
    batch_size=8
)

🎓 Training Custom Models

Train GLiNER2 on your own data to specialize for your domain or use case.

Quick Start Training

from gliner2 import GLiNER2
from gliner2.training.data import InputExample
from gliner2.training.trainer import GLiNER2Trainer, TrainingConfig

# 1. Prepare training data
examples = [
    InputExample(
        text="John works at Google in California.",
        entities={"person": ["John"], "company": ["Google"], "location": ["California"]}
    ),
    InputExample(
        text="Apple released iPhone 15.",
        entities={"company": ["Apple"], "product": ["iPhone 15"]}
    ),
    # Add more examples...
]

# 2. Configure training
model = GLiNER2.from_pretrained("fastino/gliner2-base-v1")
config = TrainingConfig(
    output_dir="./output",
    num_epochs=10,
    batch_size=8,
    encoder_lr=1e-5,
    task_lr=5e-4
)

# 3. Train
trainer = GLiNER2Trainer(model, config)
trainer.train(train_data=examples)

Training Data Format (JSONL)

GLiNER2 uses JSONL format where each line contains an input and output field:

{"input": "Tim Cook is the CEO of Apple Inc., based in Cupertino, California.", "output": {"entities": {"person": ["Tim Cook"], "company": ["Apple Inc."], "location": ["Cupertino", "California"]}, "entity_descriptions": {"person": "Full name of a person", "company": "Business organization name", "location": "Geographic location or place"}}}
{"input": "OpenAI released GPT-4 in March 2023.", "output": {"entities": {"company": ["OpenAI"], "model": ["GPT-4"], "date": ["March 2023"]}}}

Classification Example:

{"input": "This movie is absolutely fantastic! I loved every minute of it.", "output": {"classifications": [{"task": "sentiment", "labels": ["positive", "negative", "neutral"], "true_label": ["positive"]}]}}
{"input": "The service was terrible and the food was cold.", "output": {"classifications": [{"task": "sentiment", "labels": ["positive", "negative", "neutral"], "true_label": ["negative"]}]}}

Structured Extraction Example:

{"input": "iPhone 15 Pro Max with 256GB storage, priced at $1199.", "output": {"json_structures": [{"product": {"name": "iPhone 15 Pro Max", "storage": "256GB", "price": "$1199"}}]}}

Relation Extraction Example:

{"input": "John works for Apple Inc. and lives in San Francisco.", "output": {"relations": [{"works_for": {"head": "John", "tail": "Apple Inc."}}, {"lives_in": {"head": "John", "tail": "San Francisco"}}]}}

Training from JSONL File

from gliner2 import GLiNER2
from gliner2.training.trainer import GLiNER2Trainer, TrainingConfig

# Load model and train from JSONL file
model = GLiNER2.from_pretrained("fastino/gliner2-base-v1")
config = TrainingConfig(output_dir="./output", num_epochs=10)

trainer = GLiNER2Trainer(model, config)
trainer.train(train_data="train.jsonl")  # Path to your JSONL file

LoRA Training (Parameter-Efficient Fine-Tuning)

Train lightweight adapters for domain-specific tasks:

from gliner2 import GLiNER2
from gliner2.training.data import InputExample
from gliner2.training.trainer import GLiNER2Trainer, TrainingConfig

# Prepare domain-specific data
legal_examples = [
    InputExample(
        text="Apple Inc. filed a lawsuit against Samsung Electronics.",
        entities={"company": ["Apple Inc.", "Samsung Electronics"]}
    ),
    # Add more examples...
]

# Configure LoRA training
model = GLiNER2.from_pretrained("fastino/gliner2-base-v1")
config = TrainingConfig(
    output_dir="./legal_adapter",
    num_epochs=10,
    batch_size=8,
    encoder_lr=1e-5,
    task_lr=5e-4,
    
    # LoRA settings
    use_lora=True,                    # Enable LoRA
    lora_r=8,                         # Rank (4, 8, 16, 32)
    lora_alpha=16.0,                  # Scaling factor (usually 2*r)
    lora_dropout=0.0,                 # Dropout for LoRA layers
    save_adapter_only=True            # Save only adapter (~5MB vs ~450MB)
)

# Train adapter
trainer = GLiNER2Trainer(model, config)
trainer.train(train_data=legal_examples)

# Use the adapter
model.load_adapter("./legal_adapter/final")
results = model.extract_entities(legal_text, ["company", "law"])

Benefits of LoRA:

Smaller size: Adapters are ~2-10 MB vs ~450 MB for full models
Faster training: 2-3x faster than full fine-tuning
Easy switching: Swap adapters in milliseconds for different domains

Complete Training Example

from gliner2 import GLiNER2
from gliner2.training.data import InputExample, TrainingDataset
from gliner2.training.trainer import GLiNER2Trainer, TrainingConfig

# Prepare training data
train_examples = [
    InputExample(
        text="Tim Cook is the CEO of Apple Inc., based in Cupertino, California.",
        entities={
            "person": ["Tim Cook"],
            "company": ["Apple Inc."],
            "location": ["Cupertino", "California"]
        },
        entity_descriptions={
            "person": "Full name of a person",
            "company": "Business organization name",
            "location": "Geographic location or place"
        }
    ),
    # Add more examples...
]

# Create and validate dataset
train_dataset = TrainingDataset(train_examples)
train_dataset.validate(strict=True, raise_on_error=True)
train_dataset.print_stats()

# Split into train/validation
train_data, val_data, _ = train_dataset.split(
    train_ratio=0.8,
    val_ratio=0.2,
    test_ratio=0.0,
    shuffle=True,
    seed=42
)

# Configure training
model = GLiNER2.from_pretrained("fastino/gliner2-base-v1")
config = TrainingConfig(
    output_dir="./ner_model",
    experiment_name="ner_training",
    num_epochs=15,
    batch_size=16,
    encoder_lr=1e-5,
    task_lr=5e-4,
    warmup_ratio=0.1,
    scheduler_type="cosine",
    fp16=True,
    eval_strategy="epoch",
    save_best=True,
    early_stopping=True,
    early_stopping_patience=3
)

# Train
trainer = GLiNER2Trainer(model, config)
trainer.train(train_data=train_data, val_data=val_data)

# Load best model
model = GLiNER2.from_pretrained("./ner_model/best")

For more details, see the Training Tutorial and Data Format Guide.

📄 License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

📚 Citation

If you use GLiNER2 in your research, please cite:

@inproceedings{zaratiana-etal-2025-gliner2,
    title = "{GL}i{NER}2: Schema-Driven Multi-Task Learning for Structured Information Extraction",
    author = "Zaratiana, Urchade  and
      Pasternak, Gil  and
      Boyd, Oliver  and
      Hurn-Maloney, George  and
      Lewis, Ash",
    editor = {Habernal, Ivan  and
      Schulam, Peter  and
      Tiedemann, J{\"o}rg},
    booktitle = "Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: System Demonstrations",
    month = nov,
    year = "2025",
    address = "Suzhou, China",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2025.emnlp-demos.10/",
    pages = "130--140",
    ISBN = "979-8-89176-334-0",
    abstract = "Information extraction (IE) is fundamental to numerous NLP applications, yet existing solutions often require specialized models for different tasks or rely on computationally expensive large language models. We present GLiNER2, a unified framework that enhances the original GLiNER architecture to support named entity recognition, text classification, and hierarchical structured data extraction within a single efficient model. Built on a fine-tuned encoder architecture, GLiNER2 maintains CPU efficiency and compact size while introducing multi-task composition through an intuitive schema-based interface. Our experiments demonstrate competitive performance across diverse IE tasks with substantial improvements in deployment accessibility compared to LLM-based alternatives. We release GLiNER2 as an open-source library available through pip, complete with pre-trained models and comprehensive documentation."
}

🙏 Acknowledgments

Built upon the original GLiNER architecture by the team at Fastino AI.

Ready to extract insights from your data?
pip install gliner2