spacy vs Relativity
Side-by-side comparison to help you choose.
| Feature | spacy | Relativity |
|---|---|---|
| Type | Repository | Product |
| UnfragileRank | 26/100 | 32/100 |
| Adoption | 0 | 0 |
| Quality | 0 | 1 |
| Ecosystem | 0 |
| 0 |
| Match Graph | 0 | 0 |
| Pricing | Free | Paid |
| Capabilities | 14 decomposed | 13 decomposed |
| Times Matched | 0 | 0 |
Breaks raw text into tokens using a Cython-compiled tokenizer (spacy/tokenizer.pyx) that applies language-specific exception rules and morphological boundaries. The tokenizer maintains a rule registry per language and uses finite-state matching to handle contractions, punctuation, and special cases (e.g., 'don't' → ['do', "n't"]). Tokens are stored as lightweight views into a Doc's underlying TokenC struct array, enabling zero-copy access to token attributes.
Unique: Uses Cython-compiled C-structs (TokenC) with interned string storage (StringStore) to achieve O(1) token attribute access and near-C performance while maintaining Python API. Token and Span objects are zero-copy views into Doc's memory, not independent allocations.
vs alternatives: Faster than NLTK's regex-based tokenizer and more memory-efficient than spaCy's pure-Python alternatives because it uses compiled C-structs and string interning instead of creating Python objects per token.
Implements a transition-based dependency parser (spacy/pipeline/parser.pyx) that uses a neural network to predict syntactic head-dependent relationships. The parser maintains a shift-reduce state machine, processing tokens left-to-right and predicting transitions (shift, left-arc, right-arc) via a feed-forward or transformer-based neural model. Parsed dependencies are stored in the Doc's head and dep attributes, enabling downstream tasks like relation extraction and semantic role labeling.
Unique: Uses a transition-based parser with Cython-optimized state management and neural predictions, avoiding the O(n³) complexity of graph-based parsers. Integrates with spaCy's pipeline architecture so parsing output (head, dep) is cached in Doc and reused by downstream components.
vs alternatives: Faster than Stanford CoreNLP's graph-based parser (O(n) vs O(n³)) and more accurate than rule-based parsers; integrates seamlessly with spaCy's other components (NER, POS tagging) in a single pipeline.
Maintains language-specific data (tokenization rules, morphological features, stop words, lemmatization rules) in JSON files (website/meta/languages.json) that are loaded at runtime. Each language has a Language subclass (e.g., English, German, French) that defines language-specific tokenization exceptions and morphological rules. Users can add custom languages by creating a new Language subclass and registering it with @Language.factory. The system supports 70+ languages with unified API despite diverse linguistic properties.
Unique: Defines language-specific rules in declarative JSON files (website/meta/languages.json) rather than hardcoding them, enabling easy addition of new languages. Language subclasses can override tokenization and morphology methods, allowing fine-grained customization per language.
vs alternatives: More maintainable than monolithic language-specific code because rules are data-driven; more flexible than fixed language lists because new languages can be added by creating a Language subclass.
Serializes trained models to disk in a binary format that preserves all components, configuration, and weights. Models are saved as directories containing component files (e.g., model.pkl for neural weights), config.cfg, and metadata.json. Deserialization loads the model back into memory with all components ready for inference. The system supports incremental model updates (e.g., adding new entities to NER without retraining) via component-level serialization.
Unique: Serializes entire Language objects including all components, configuration, and weights to a single directory. Component-level serialization allows incremental updates (e.g., updating NER without retraining parser).
vs alternatives: More complete than pickle-based serialization because it preserves configuration and metadata; more efficient than JSON serialization because binary format is more compact.
Allows users to attach custom attributes to Token, Doc, and Span objects via the extension system (Token.set_extension, Doc.set_extension, Span.set_extension). Extensions can be properties (computed on-the-fly), attributes (stored in memory), or methods. Extensions are registered globally and available on all instances of the target class. This enables adding domain-specific metadata (e.g., sentiment scores, custom NER labels) without modifying spaCy's core classes.
Unique: Uses a global extension registry (spacy/tokens/token.pyx) that allows attaching arbitrary attributes to core classes without subclassing. Extensions can be properties (computed on-the-fly) or attributes (stored in memory), enabling flexible metadata management.
vs alternatives: More flexible than subclassing because it doesn't require creating custom Token/Doc classes; more efficient than storing metadata in separate dictionaries because extensions are directly accessible via dot notation.
Provides batch processing via the nlp.pipe() method that processes multiple documents efficiently by batching them through the pipeline. Internally, spaCy uses DocBin format to store multiple Doc objects in a single binary file, enabling efficient serialization and deserialization. The system supports streaming processing where documents are yielded as they're processed, enabling memory-efficient handling of large corpora.
Unique: Uses nlp.pipe() for streaming batch processing where documents are yielded as processed, avoiding memory overhead of loading all documents upfront. DocBin format enables efficient serialization of multiple Doc objects with shared Vocab.
vs alternatives: More memory-efficient than processing documents individually because it batches them through the pipeline; more efficient than storing Doc objects in memory because DocBin uses binary format with shared string interning.
Combines two NER approaches: (1) neural sequence labeling via a BiLSTM or transformer model that predicts BIO tags (Begin, Inside, Outside) for each token, and (2) rule-based matching using PhraseMatcher and Matcher for pattern-based entity extraction. Neural predictions are stored in the Doc's ents attribute; rule-based matches can be added via EntityRuler pipeline component. Both approaches integrate into a unified Doc.ents interface, allowing hybrid NER systems.
Unique: Integrates neural sequence labeling (BiLSTM/transformer) with rule-based matching (Matcher/PhraseMatcher) in a single pipeline, allowing users to combine statistical and symbolic approaches. EntityRuler component can override or augment neural predictions, enabling hybrid systems without custom code.
vs alternatives: More flexible than pure neural NER (e.g., Hugging Face transformers) because it allows rule-based augmentation; more accurate than pure rule-based systems because it leverages pre-trained neural models. Faster than spaCy v2 because it uses transformer-based models with GPU support.
Assigns part-of-speech (POS) tags and morphological features (tense, mood, case, gender, number) to each token using a statistical tagger trained on annotated corpora. The tagger uses a feed-forward neural network or transformer to predict tags based on word embeddings and context. Morphological features are stored in the Token.morph attribute as a MorphAnalysis object, enabling fine-grained linguistic analysis. The system supports 70+ languages with language-specific tagsets (e.g., Universal Dependencies).
Unique: Stores morphological features in a MorphAnalysis object (spacy/morphology.pyx) that acts as a lazy-loaded feature dictionary, avoiding memory overhead while providing O(1) feature access. Supports 70+ languages with unified API despite diverse morphological systems.
vs alternatives: More accurate than rule-based taggers (e.g., NLTK) because it uses neural models trained on large corpora; more memory-efficient than storing full feature dicts per token because MorphAnalysis uses string interning and lazy parsing.
+6 more capabilities
Automatically categorizes and codes documents based on learned patterns from human-reviewed samples, using machine learning to predict relevance, privilege, and responsiveness. Reduces manual review burden by identifying documents that match specified criteria without human intervention.
Ingests and processes massive volumes of documents in native formats while preserving metadata integrity and creating searchable indices. Handles format conversion, deduplication, and metadata extraction without data loss.
Provides tools for organizing and retrieving documents during depositions and trial, including document linking, timeline creation, and quick-search capabilities. Enables attorneys to rapidly locate supporting documents during proceedings.
Manages documents subject to regulatory requirements and compliance obligations, including retention policies, audit trails, and regulatory reporting. Tracks document lifecycle and ensures compliance with legal holds and preservation requirements.
Manages multi-reviewer document review workflows with task assignment, progress tracking, and quality control mechanisms. Supports parallel review by multiple team members with conflict resolution and consistency checking.
Enables rapid searching across massive document collections using full-text indexing, Boolean operators, and field-specific queries. Supports complex search syntax for precise document retrieval and filtering.
Relativity scores higher at 32/100 vs spacy at 26/100. However, spacy offers a free tier which may be better for getting started.
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Identifies and flags privileged communications (attorney-client, work product) and confidential information through pattern recognition and metadata analysis. Maintains comprehensive audit trails of all access to sensitive materials.
Implements role-based access controls with fine-grained permissions at document, workspace, and field levels. Allows administrators to restrict access based on user roles, case assignments, and security clearances.
+5 more capabilities