# langextract | Google | Knowledge Base | Instagit

A Python library for extracting structured information from unstructured text using LLMs with precise source grounding and interactive visualization.

GitHub Stars: 32.5k

Repository: https://github.com/google/langextract

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## Articles

### [How to Create Custom Provider Plugins for LangExtract: A Complete Developer's Guide](/google/langextract/how-to-create-custom-provider-plugins-for-langextract)

Learn how to create custom provider plugins for LangExtract. Follow this developer's guide to extend LangExtract functionality with your own language model providers.

- Tags: how-to-guide
- Published: 2026-02-19

### [How to Debug LangExtract Extraction Issues Using Debug Mode](/google/langextract/how-to-debug-langextract-extraction-issues-with-debug-mode)

Debug LangExtract extraction issues efficiently using debug mode. Enable debug=True in langextract.extraction.extract() for detailed pipeline logging and insight into tokenization, resolution, and LLM calls.

- Tags: how-to-guide
- Published: 2026-02-19

### [How LangExtract Handles Rate Limits and Quota Management: A Complete Guide](/google/langextract/how-does-langextract-handle-rate-limits-and-quota-management)

Learn how LangExtract helps manage LLM provider quotas with batching, caching, and concurrency controls. Understand its client-side approach to staying within limits.

- Tags: how-to-guide
- Published: 2026-02-16

### [How LangExtract Handles Overlapping Extractions Across Multiple Passes](/google/langextract/how-does-langextract-handle-overlapping-extractions-across-passes)

LangExtract resolves overlapping extractions across passes with a first-pass wins policy. Discover how earlier extractions take precedence and later ones are discarded.

- Tags: internals
- Published: 2026-02-16

### [How to Use LangExtract with Google Vertex AI Authentication: Enterprise Deployment Guide](/google/langextract/how-to-use-langextract-with-google-vertex-ai-authentication)

Securely deploy LangExtract with Google Vertex AI authentication. Set vertexai=True for IAM security, managed quotas, and VPC networking. Learn how to integrate now.

- Tags: how-to-guide
- Published: 2026-02-16

### [How to Handle Extraction Errors and Parse Failures in LangExtract](/google/langextract/how-to-handle-extraction-errors-and-parse-failures-in-langextract)

Learn to handle LangExtract errors and parse failures. Use suppress_parse_errors or catch ResolverParsingError for robust LLM output processing.

- Tags: how-to-guide
- Published: 2026-02-16

### [LangExtract Factory Pattern: How to Create Language Models Programmatically](/google/langextract/how-does-langextract-integrate-with-the-factory-pattern-for-model-creation)

Discover how LangExtract uses the factory pattern to programmatically create language models via the create_model function. Learn about ModelConfig and dynamic provider resolution.

- Tags: how-to-guide
- Published: 2026-02-16

### [How to Optimize LangExtract Performance for Large-Scale Extraction](/google/langextract/how-to-optimize-langextract-performance-for-large-scale-extraction)

Boost LangExtract performance for large-scale extraction by tuning max char buffer, batch length, and using the fast RegexTokenizer. Learn optimization techniques for efficient text analysis.

- Tags: performance
- Published: 2026-02-16

### [How to Configure LangExtract's Format Handler for JSON vs YAML](/google/langextract/how-to-configure-langextracts-format-handler-for-json-vs-yaml)

Configure LangExtract's format handler for JSON or YAML. Learn to control output parsing with flags like use_fences and use_wrapper for efficient data extraction.

- Tags: how-to-guide
- Published: 2026-02-16

### [How context_window_chars Improves Coreference Resolution in LangExtract](/google/langextract/how-does-context-window-chars-help-with-coreference-resolution)

Learn how context_window_chars enhances coreference resolution in LangExtract by providing crucial context across text chunks. Improve pronoun and reference accuracy.

- Tags: deep-dive
- Published: 2026-02-16

### [How to Use LangExtract's Visualization for Extracted Entities: A Complete Guide](/google/langextract/how-to-use-langextracts-visualization-for-extracted-entities)

Learn to use LangExtract's visualization tool to highlight extracted entities in text with interactive HTML pages color-coded spans and playback controls. A complete guide for google/langextract.

- Tags: how-to-guide
- Published: 2026-02-16

### [How LangExtract Handles Fuzzy Text Alignment: A Deep Dive into the Algorithm](/google/langextract/how-does-langextract-handle-fuzzy-text-alignment)

Learn how the google/langextract tool handles fuzzy text alignment. It uses a two-stage pipeline with difflib and a sliding-window approach for robust matching.

- Tags: deep-dive
- Published: 2026-02-16

### [How to Configure Custom Model Providers in LangExtract: A Complete Guide](/google/langextract/how-to-configure-custom-model-providers-in-langextract)

Configure custom model providers in LangExtract by implementing BaseLanguageModel, registering with lx.providers.registry.register, and exposing via pyproject.toml entry points. Learn more!

- Tags: how-to-guide
- Published: 2026-02-16

### [How to Configure OpenAI Models with LangExtract: A Complete Guide](/google/langextract/how-to-configure-openai-models-with-langextract)

Configure OpenAI models with LangExtract easily. Learn how LangExtract automatically routes requests, handles formatting, and simplifies batch inference for your projects.

- Tags: how-to-guide
- Published: 2026-02-16

### [How LangExtract's Resolver Parses and Aligns Extractions: A Deep Dive into the Core Pipeline](/google/langextract/how-does-langextracts-resolver-parse-and-align-extractions)

Learn how LangExtract's resolver parses LLM output into structured data. Discover its two-stage pipeline for text parsing and extraction alignment using exact and fuzzy matching.

- Tags: deep-dive
- Published: 2026-02-16

### [How to Use LangExtract with Local Ollama Models: A Complete Guide](/google/langextract/how-to-use-langextract-with-local-ollama-models)

Integrate LangExtract with local Ollama models to extract structured data. Easily use any model by passing its ID and configuring the Ollama format handler. Get started now.

- Tags: how-to-guide
- Published: 2026-02-16

### [How LangExtract Processes Long Documents with Chunking and Parallel Workers](/google/langextract/how-does-langextract-process-long-documents-with-chunking-and-parallel-workers)

LangExtract processes long documents via chunking and parallel workers. Learn how text splitting and batch processing maximize throughput while respecting LLM context limits.

- Tags: internals
- Published: 2026-02-16

### [How to Use Vertex AI Batch Processing in LangExtract: A Complete Implementation Guide](/google/langextract/how-to-use-vertex-ai-batch-processing-in-langextract)

Learn how to use Vertex AI batch processing with LangExtract. Automatically handle large workloads with GCS uploads, job polling, and result caching for efficient processing.

- Tags: how-to-guide
- Published: 2026-02-16

### [LangExtract Prompt Validation and Alignment: How Google Validates Few-Shot Prompts](/google/langextract/how-does-langextract-handle-prompt-validation-and-alignment)

LangExtract validates few-shot prompt alignment verifying extraction annotations match source text using exact and fuzzy matching. Configure validation levels for warnings or prompt alignment errors.

- Tags: how-to-guide
- Published: 2026-02-16

### [How `extraction_passes` Improves Recall in LangExtract: Multi-Pass Extraction Explained](/google/langextract/how-does-extraction-passes-improve-recall-in-langextract)

Learn how LangExtract's extraction_passes improve recall. Discover sequential multi-pass extraction for better entity identification and higher accuracy with Google's LangExtract.

- Tags: deep-dive
- Published: 2026-02-16

### [How LangExtract Handles Source Grounding and Text Alignment: A Technical Deep Dive](/google/langextract/how-does-langextract-handle-source-grounding-and-text-alignment)

Discover how LangExtract grounds LLM extractions to source text. Learn about its three-stage pipeline using exact and fuzzy alignment for accurate results. Explore char_interval token_interval and alignment_status.

- Tags: deep-dive
- Published: 2026-02-16

### [How LangExtract Handles Schema Constraints with Gemini Models: A Deep Dive into Structured Output](/google/langextract/how-does-langextract-handle-schema-constraints-with-gemini-models)

Discover how LangExtract enforces schema constraints with Gemini models. Learn to automatically generate JSON schemas and validate Gemini's structured output for cleaner data extraction.

- Tags: deep-dive
- Published: 2026-02-16

### [Optimizing LangExtract Performance for Long Documents: 8 Proven Strategies](/google/langextract/strategies-for-optimizing-langextract-performance-with-long-documents)

Boost LangExtract performance for long documents. Learn 8 proven strategies to tune chunk buffers, batch sizes, and worker pools for efficient parallel processing and reduced API calls.

- Tags: performance
- Published: 2026-02-16

### [How LangExtract Performs Source Grounding to Map Extractions to Text Locations](/google/langextract/how-does-langextract-perform-source-grounding-to-map-extractions-to-text-locations)

Learn how LangExtract grounds extractions to text locations using tokenization, exact matching with difflib, and fuzzy matching for accurate results.

- Tags: internals
- Published: 2026-02-16

### [How LangExtract Chunking, Parallel Processing, and Multi-Pass Strategy Work: A Deep Dive](/google/langextract/how-does-langextracts-chunking-parallel-processing-and-multi-pass-strategy-work)

Explore how LangExtract's chunking, parallel processing, and multi-pass strategy enhance text extraction recall. Learn about ThreadPoolExecutor and batch processing.

- Tags: deep-dive
- Published: 2026-02-16