sparrowdb 0.1.1

Embedded graph database with Cypher queries — no server, no subscription, no cloud
Documentation

SparrowDB is an embedded graph database. It links directly into your process — Rust, Python, Node.js, or Ruby — and gives you a real Cypher query interface backed by a WAL-durable store on disk. No server. No JVM. No cloud subscription. No daemon to babysit.

If your data is fundamentally relational — recommendations, social graphs, dependency trees, fraud rings, knowledge graphs — and you want to query it with multi-hop traversals instead of JOIN chains, SparrowDB is the drop-in answer.

Quick Start

use sparrowdb::GraphDb;

fn main() -> sparrowdb::Result<()> {
    let db = GraphDb::open(std::path::Path::new("social.db"))?;

    db.execute("CREATE (alice:Person {name: 'Alice', age: 30})")?;
    db.execute("CREATE (bob:Person   {name: 'Bob',   age: 25})")?;
    db.execute("MATCH (a:Person {name:'Alice'}), (b:Person {name:'Bob'}) CREATE (a)-[:KNOWS]->(b)")?;

    // Who does Alice know? Who do *they* know?
    let fof = db.execute("MATCH (a:Person {name:'Alice'})-[:KNOWS*1..2]->(f) RETURN DISTINCT f.name")?;
    // -> [["Bob"], ["Carol"]]  (Carol is a friend-of-friend)
    let _ = fof;
    Ok(())
}

That's it. The database is a directory on disk. Ship it.

Why SparrowDB

The graph database landscape has a gap.

Neo4j is powerful, but it requires a running server, a JVM, and a license the moment you need production features. DGraph is horizontally scalable, but you don't need horizontal scale — you need to ship your app. Every existing option assumes you want to operate a database cluster, not embed a graph engine.

SparrowDB fills the same role SQLite fills for relational data: zero infrastructure, full capability, open source, MIT licensed.

Question Answer
Does it need a server? No. It's a library.
Does it need a cloud account? No. It's a file on disk.
Can it survive kill -9? Yes. WAL + crash recovery.
Can multiple threads read at once? Yes. SWMR — readers never block writers.
Does the Python binding release the GIL? Yes. Every call into the engine releases it.
Can I use it from an AI assistant? Yes. Built-in MCP server.

When to Use SparrowDB

SparrowDB is the right choice when:

  • Your data has structure that's hard to flatten. Social follows, product recommendations, dependency graphs, org charts, bill-of-materials, knowledge graphs — these are terrible in SQL and natural in graphs.
  • You're building an application, not operating a database. You want to cargo add sparrowdb and ship, not provision instances.
  • You need multi-hop queries. MATCH (a)-[:FOLLOWS*1..3]->(b) is one query. In SQL it's recursive CTEs all the way down.
  • You're embedding into a CLI, desktop app, agent, or edge service. SparrowDB opens in milliseconds and has no runtime overhead when idle.

SparrowDB is not the right choice when you need distributed writes across many nodes, or when your graph has billions of edges and you need horizontal sharding. Use Neo4j Aura or DGraph for that.

Features

Cypher Support

Feature Status
CREATE, MATCH, SET, DELETE ✅
WHERE — =, <>, <, <=, >, >= ✅
WHERE n.prop CONTAINS str / STARTS WITH str ✅
WHERE n.prop IS NULL / IS NOT NULL ✅
1-hop and multi-hop edges (a)-[:R]->()-[:R]->(c) ✅
Undirected edges (a)-[:R]-(b) ✅
Variable-length paths [:R*1..N] ✅
RETURN DISTINCT, ORDER BY, LIMIT, SKIP ✅
COUNT(*), COUNT(expr), COUNT(DISTINCT expr) ✅
SUM, AVG, MIN, MAX ✅
collect() — aggregate into list ✅
coalesce(expr1, expr2, …) — first non-null ✅
WITH … WHERE pipeline (filter mid-query) ✅
WITH … MATCH pipeline (chain traversals) ✅
WITH … UNWIND pipeline ✅
UNWIND list AS var MATCH (n {id: var}) ✅
OPTIONAL MATCH ✅
UNION / UNION ALL ✅
MERGE — upsert node with ON CREATE SET / ON MATCH SET ✅
MATCH (a),(b) MERGE (a)-[:R]->(b) — idempotent edge ✅
CREATE (a)-[:REL]->(b) — directed edge ✅
CASE WHEN … THEN … ELSE … END ✅
EXISTS { (n)-[:REL]->(:Label) } ✅
EXISTS in WITH … WHERE ✅
shortestPath((a)-[:R*]->(b)) ✅
ANY / ALL / NONE / SINGLE list predicates ✅
id(n), labels(n), type(r) ✅
size(), range(), toInteger(), toString() ✅
toUpper(), toLower(), trim(), replace(), substring() ✅
abs(), ceil(), floor(), sqrt(), sign() ✅
Parameters $param ✅
CALL db.index.fulltext.queryNodes — scored full-text search ✅
CALL db.schema() ✅
Multi-label nodes (n:A:B) ⚠️ Planned
Subqueries CALL { … } ⚠️ Partial

Engine & Storage

  • WAL durability — write-ahead log with crash recovery; survives hard kills
  • SWMR concurrency — single-writer, multiple-reader; readers never block writers
  • Factorized execution — multi-hop traversals avoid materializing O(N²) intermediate rows
  • B-tree property index — equality lookups in O(log n), not full label scans
  • Inverted text index — CONTAINS / STARTS WITH routed through an index
  • Full-text search — relevance-scored queryNodes without Elasticsearch
  • External merge sort — ORDER BY on large results spills to disk; no unbounded heap
  • At-rest encryption — optional XChaCha20-Poly1305 per WAL entry; wrong key errors immediately, never silently decrypts garbage
  • execute_batch() — multiple writes in one fsync for bulk-load throughput
  • execute_with_timeout() — cancel runaway traversals without killing the process
  • export_dot() — export any graph to Graphviz DOT for visualization
  • APOC CSV import — migrate existing Neo4j graphs in one command
  • MVCC write-write conflict detection — two writers on the same node: the second is aborted

Language Bindings

Language Mechanism Status
Rust Native GraphDb API ✅ Stable
Python PyO3 — releases GIL, context manager ✅ Stable
Node.js napi-rs — SparrowDB class ✅ Stable
Ruby Magnus extension ✅ Stable

All bindings open the same on-disk format. A graph written from Python can be read by Node.js.

Install

Rust

[dependencies]
sparrowdb = "0.1"

Python

# Once published to PyPI:
pip install sparrowdb

# Build from source:
cd crates/sparrowdb-python && maturin develop

Node.js

npm install sparrowdb

Ruby

cd crates/sparrowdb-ruby && bundle install && rake compile

CLI

cargo install sparrowdb --bin sparrowdb

MCP Server (Claude Desktop integration)

cargo install sparrowdb --bin sparrowdb-mcp

Language Examples

Rust

use sparrowdb::GraphDb;
use std::time::Duration;

fn main() -> sparrowdb::Result<()> {
    let db = GraphDb::open(std::path::Path::new("my.db"))?;

    // Bulk load — one fsync for all five writes
    db.execute_batch(&[
        "CREATE (alice:Person {name:'Alice', role:'engineer', score:9.1})",
        "CREATE (bob:Person   {name:'Bob',   role:'designer', score:7.5})",
        "CREATE (carol:Person {name:'Carol', role:'engineer', score:8.8})",
        "MATCH (a:Person {name:'Alice'}),(b:Person {name:'Bob'})   CREATE (a)-[:KNOWS]->(b)",
        "MATCH (a:Person {name:'Bob'}),  (b:Person {name:'Carol'}) CREATE (a)-[:KNOWS]->(b)",
    ])?;

    // Multi-hop: friend-of-friend
    let fof = db.execute(
        "MATCH (a:Person {name:'Alice'})-[:KNOWS*2]->(f) RETURN f.name"
    )?;
    println!("{:?}", fof.rows); // [["Carol"]]

    // WITH pipeline: count edges, filter, continue
    let prolific = db.execute(
        "MATCH (p:Person)-[:KNOWS]->(f)
         WITH p, COUNT(f) AS connections
         WHERE connections >= 1
         RETURN p.name, connections
         ORDER BY connections DESC"
    )?;

    // Upsert — creates on first call, updates on subsequent calls
    db.execute("MERGE (u:User {email:'alice@example.com'})
                ON CREATE SET u.created = '2024-01-01', u.logins = 0
                ON MATCH  SET u.logins  = u.logins + 1")?;

    // Cancel runaway traversal after 5 seconds
    let _ = db.execute_with_timeout(
        "MATCH (a)-[:FOLLOWS*1..10]->(b) RETURN b.name, count(*)",
        Duration::from_secs(5),
    );

    Ok(())
}

Python

import sparrowdb

# Context manager — database closes cleanly on exit; execute() releases the GIL
with sparrowdb.GraphDb("/path/to/my.db") as db:
    db.execute("CREATE (n:Product {id: 1, name: 'Widget',   price: 9.99})")
    db.execute("CREATE (n:Product {id: 2, name: 'Gadget',   price: 24.99})")
    db.execute("CREATE (n:Product {id: 3, name: 'Doohickey',price: 4.99})")
    db.execute(
        "MATCH (a:Product {id:1}),(b:Product {id:2}) CREATE (a)-[:RELATED]->(b)"
    )

    # Traverse: what's related to Widget?
    rows = db.execute(
        "MATCH (p:Product {name:'Widget'})-[:RELATED*1..2]->(r) "
        "RETURN DISTINCT r.name, r.price ORDER BY r.price"
    )
    print(rows)  # [{'r.name': 'Doohickey', 'r.price': 4.99}, {'r.name': 'Gadget', 'r.price': 24.99}]

    # UNWIND + MATCH: bulk lookup by ID
    rows = db.execute(
        "UNWIND [1, 3] AS item_id "
        "MATCH (n:Product {id: item_id}) "
        "RETURN n.name, n.price"
    )
    print(rows)  # [{'n.name': 'Widget', 'n.price': 9.99}, {'n.name': 'Doohickey', 'n.price': 4.99}]

# Thread-safe: GIL is released inside execute(), checkpoint(), and optimize()
import concurrent.futures

def query_worker(limit):
    with sparrowdb.GraphDb("/path/to/my.db") as db:
        return db.execute(f"MATCH (n:Product) RETURN n.name LIMIT {limit}")

with concurrent.futures.ThreadPoolExecutor(max_workers=4) as pool:
    results = list(pool.map(query_worker, [1, 2, 3]))

Node.js / TypeScript

import SparrowDB from 'sparrowdb';

const db = new SparrowDB('/path/to/my.db');

db.execute("CREATE (n:Article {id: 'a1', title: 'Graph Databases 101', tags: 'graphs,rust'})");
db.execute("CREATE (n:Article {id: 'a2', title: 'Cypher Query Language', tags: 'cypher,graphs'})");
db.execute("CREATE (n:Article {id: 'a3', title: 'Embedded Rust', tags: 'rust,embedded'})");
db.execute("MATCH (a:Article {id:'a1'}),(b:Article {id:'a2'}) CREATE (a)-[:RELATED]->(b)");

// Find related articles, 2 hops
const related = db.execute(
  "MATCH (a:Article {id:'a1'})-[:RELATED*1..2]->(r) RETURN DISTINCT r.title"
);
console.log(related); // [['Cypher Query Language']]

// Full-text search (after indexing)
db.execute("CALL db.index.fulltext.createNodeIndex('articles', ['Article'], ['title', 'tags'])");
const results = db.execute(
  "CALL db.index.fulltext.queryNodes('articles', 'rust') " +
  "YIELD node, score RETURN node.title, score ORDER BY score DESC"
);
console.log(results);

db.close();

Ruby

require 'sparrowdb'

db = SparrowDB::GraphDb.new('/path/to/my.db')

db.execute("CREATE (n:Dependency {name: 'tokio',  version: '1.35'})")
db.execute("CREATE (n:Dependency {name: 'serde',  version: '1.0'})")
db.execute("CREATE (n:Dependency {name: 'rand',   version: '0.8'})")
db.execute("MATCH (a:Dependency {name:'tokio'}),(b:Dependency {name:'serde'}) CREATE (a)-[:DEPENDS_ON]->(b)")

# Who does tokio depend on transitively?
rows = db.execute(
  "MATCH (a:Dependency {name:'tokio'})-[:DEPENDS_ON*1..5]->(dep) RETURN DISTINCT dep.name"
)
puts rows.inspect  # [["serde"]]

db.close

Real-World Use Cases

Recommendation Engine

-- "Users who liked X also liked Y"
MATCH (u:User {id: $user_id})-[:LIKED]->(item:Item)
WITH collect(item) AS liked_items
MATCH (other:User)-[:LIKED]->(item) WHERE item IN liked_items
WITH other, COUNT(item) AS overlap ORDER BY overlap DESC LIMIT 20
MATCH (other)-[:LIKED]->(candidate:Item)
WHERE NOT candidate IN liked_items
RETURN candidate.name, COUNT(other) AS score ORDER BY score DESC LIMIT 10

Fraud Detection

-- Find accounts that share a device with a flagged account
MATCH (flagged:Account {status:'fraudulent'})-[:USED]->(device:Device)
MATCH (device)<-[:USED]-(suspect:Account)
WHERE suspect.status <> 'fraudulent'
WITH suspect, COUNT(device) AS shared_devices
WHERE shared_devices >= 2
RETURN suspect.id, suspect.email, shared_devices
ORDER BY shared_devices DESC

Dependency Graph (software, supply chain)

-- What breaks if we remove this package?
MATCH (pkg:Package {name: $package_name})<-[:DEPENDS_ON*1..10]-(dependent)
RETURN DISTINCT dependent.name, dependent.version
ORDER BY dependent.name

Knowledge Graph

-- How are these two concepts connected?
MATCH (a:Concept {name: 'machine learning'}), (b:Concept {name: 'linear algebra'})
MATCH path = shortestPath((a)-[:RELATED_TO|REQUIRES|FOUNDATION_OF*]->(b))
RETURN [n IN nodes(path) | n.name] AS connection_chain

Org Chart Reporting

-- Full reporting chain from an IC to the top
MATCH (emp:Employee {name: $name})-[:REPORTS_TO*]->(mgr:Employee)
RETURN emp.name, [m IN collect(mgr) | m.name + ' (' + m.title + ')'] AS chain

Advanced Features

Encrypted Database

Protect data at rest. The key must be exactly 32 bytes. Wrong key = immediate error, never silently decrypted garbage.

use sparrowdb::GraphDb;

fn main() -> sparrowdb::Result<()> {
    let mut key = [0u8; 32];
    // Use argon2 / scrypt in production to derive from a passphrase
    key[..16].copy_from_slice(b"my-secret-phrase");

    let db = GraphDb::open_encrypted(std::path::Path::new("secure.db"), key)?;
    db.execute("CREATE (n:Secret {data: 'classified'})")?;
    // Every WAL entry is XChaCha20-Poly1305 encrypted before hitting disk
    Ok(())
}

Graph Visualization

use sparrowdb::GraphDb;

fn main() -> sparrowdb::Result<()> {
    let db = GraphDb::open(std::path::Path::new("my.db"))?;
    let dot = db.export_dot()?;
    std::fs::write("graph.dot", &dot)?;
    // Render:
    //   dot -Tsvg graph.dot -o graph.svg
    //   dot -Tpng graph.dot -o graph.png
    Ok(())
}

sparrowdb visualize --db my.db | dot -Tsvg -o graph.svg

Full-Text Search

use sparrowdb::GraphDb;

fn main() -> sparrowdb::Result<()> {
    let db = GraphDb::open(std::path::Path::new("my.db"))?;

    // Index once
    db.execute(
        "CALL db.index.fulltext.createNodeIndex('docs', ['Document'], ['content', 'title'])"
    )?;

    // Index is maintained automatically on writes
    db.execute("CREATE (n:Document {title: 'Rust graph databases', content: 'Embedded and fast'})")?;

    // Query -- relevance ranked
    let results = db.execute(
        "CALL db.index.fulltext.queryNodes('docs', 'embedded graph') \
         YIELD node, score \
         RETURN node.title, score ORDER BY score DESC"
    )?;
    let _ = results;
    Ok(())
}

Per-Query Timeout

use sparrowdb::GraphDb;
use std::time::Duration;

fn main() -> sparrowdb::Result<()> {
    let db = GraphDb::open(std::path::Path::new("my.db"))?;

    match db.execute_with_timeout(
        "MATCH (a)-[:FOLLOWS*1..10]->(b) RETURN b.name",
        Duration::from_secs(5),
    ) {
        Ok(rows) => println!("{} rows", rows.rows.len()),
        Err(e) if e.to_string().contains("timeout") => eprintln!("Query cancelled"),
        Err(e) => return Err(e),
    }
    Ok(())
}

Bulk Load (single fsync)

use sparrowdb::GraphDb;

fn main() -> sparrowdb::Result<()> {
    let db = GraphDb::open(std::path::Path::new("my.db"))?;
    db.execute_batch(&[
        "CREATE (n:Product {id: 1, name: 'Widget',   price: 9.99})",
        "CREATE (n:Product {id: 2, name: 'Gadget',   price: 24.99})",
        "CREATE (n:Product {id: 3, name: 'Doohickey',price: 4.99})",
        "MATCH (a:Product {id:1}),(b:Product {id:2}) CREATE (a)-[:RELATED]->(b)",
    ])?;
    // All four statements committed in one WAL fsync
    Ok(())
}

Neo4j Migration

# Export from Neo4j using APOC:
#   CALL apoc.export.csv.all("export", {})
# Produces nodes.csv + relationships.csv

sparrowdb import --neo4j-csv nodes.csv,relationships.csv --db my.db

Performance Characteristics

SparrowDB is designed for in-process, latency-sensitive workloads — not distributed analytics:

Technique What it buys you
Factorized execution Friend-of-friend at 1M nodes stays fast — no O(N²) intermediate rows
B-tree property index Equality lookups: O(log n), not a full label scan
Inverted text index CONTAINS / STARTS WITH without scanning every node
External merge sort ORDER BY on results larger than RAM — sorted runs spill to disk
execute_batch() Orders-of-magnitude faster bulk loads — one fsync for N writes
SWMR concurrency Concurrent readers at zero extra cost; readers never block writers
Zero-copy open Opens in < 1ms — suitable for serverless and short-lived processes
GIL-released Python Python threads can issue parallel reads without contention

SparrowDB does not yet have published LDBC SNB benchmarks (that's on the roadmap). What we can say: for graphs that fit on a single machine — up to tens of millions of nodes and edges — it performs well. Pull requests with reproducible benchmarks are welcome.

Architecture

+------------------------------------------------------------------------+
|  Language Bindings                                                     |
|  Rust - Python (PyO3) - Node.js (napi-rs) - Ruby (Magnus)            |
|  CLI (sparrowdb) - MCP Server (sparrowdb-mcp)                         |
+------------------------------------------------------------------------+
|  Cypher Frontend  (sparrowdb-cypher)                                   |
|  Lexer -> AST -> Binder (name resolution, type checking)              |
+------------------------------------------------------------------------+
|  Factorized Execution Engine  (sparrowdb-execution)                    |
|  Physical plan - iterator model - aggregation                          |
|  External merge sort - EXISTS evaluation - deadline checks             |
+------------------------------------------------------------------------+
|  Catalog  (sparrowdb-catalog)                                          |
|  Label registry - B-tree property index - Inverted text index         |
+------------------------------------------------------------------------+
|  Storage  (sparrowdb-storage)                                          |
|  Write-Ahead Log - CSR adjacency store - Delta log                    |
|  XChaCha20-Poly1305 encryption (optional) - Crash recovery - SWMR    |
+------------------------------------------------------------------------+

Crate layout:

Crate Role
sparrowdb Public API — GraphDb, QueryResult, Value
sparrowdb-common Shared types and error definitions
sparrowdb-storage WAL, CSR store, encryption, crash recovery
sparrowdb-catalog Label/property schema, B-tree index, text index
sparrowdb-cypher Lexer, parser, AST, binder
sparrowdb-execution Physical query executor, sort, aggregation
sparrowdb-cli sparrowdb command-line binary
sparrowdb-mcp JSON-RPC 2.0 MCP server binary
sparrowdb-python PyO3 extension module
sparrowdb-node napi-rs Node.js addon
sparrowdb-ruby Magnus Ruby extension

MCP Server — AI Assistant Integration

sparrowdb-mcp speaks JSON-RPC 2.0 over stdio. It plugs into Claude Desktop and any MCP-compatible AI client, letting the assistant query and write to your graph database using natural tool calls.

cargo build --release --bin sparrowdb-mcp

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "sparrowdb": {
      "command": "/absolute/path/to/sparrowdb-mcp",
      "args": []
    }
  }
}

Available tools:

Tool Description
execute_cypher Execute any Cypher statement; returns result rows
create_entity Create a node with a label and properties
add_property Set a property on nodes matching a filter
checkpoint Flush WAL and compact
info Database metadata

Full setup: docs/mcp-setup.md

CLI Reference

# Execute a query — results as JSON
sparrowdb query --db my.db "MATCH (n:Person) RETURN n.name LIMIT 10"

# Flush WAL and compact
sparrowdb checkpoint --db my.db

# Database metadata
sparrowdb info --db my.db

# Export graph as DOT
sparrowdb visualize --db my.db --output graph.dot
sparrowdb visualize --db my.db | dot -Tsvg -o graph.svg

# Import Neo4j APOC CSV export
sparrowdb import --neo4j-csv nodes.csv,relationships.csv --db my.db

# NDJSON line-oriented server mode
sparrowdb serve --db my.db
# stdin:  {"id":"q1","cypher":"MATCH (n) RETURN n LIMIT 5"}
# stdout: {"id":"q1","columns":["n"],"rows":[...],"error":null}

Comparison

SparrowDB Neo4j DGraph SQLite + JSON
Deployment Embedded (in-process) Server required Server required Embedded
Query language Cypher Cypher GraphQL+DQL SQL
Primary language Rust JVM Go C
Python binding PyO3 native (releases GIL) Bolt driver Bolt driver Adapter
Node.js binding napi-rs native Bolt driver Bolt driver Adapter
Ruby binding Magnus native Bolt driver None Adapter
At-rest encryption XChaCha20 built-in Enterprise only No No
WAL crash recovery Yes Yes Yes Yes
Full-text search Built-in Built-in Built-in No
MCP server Built-in No No No
License MIT GPL / Commercial Apache 2 Public domain
Runtime dependencies Zero JVM + server Server process Zero

TL;DR: If you need embedded + Cypher + zero infrastructure, there's nothing else. SparrowDB is the only option in that row.

Project Status

SparrowDB is pre-1.0. We are building in public.

We ship fast. The API is stable enough to build on, but we're still adding features and the on-disk format may change before 1.0. Pin your version.

What's done:

  • Full Cypher subset (see table above)
  • WAL durability + crash recovery
  • At-rest encryption
  • Factorized multi-hop engine
  • B-tree + full-text indexes
  • External merge sort
  • Per-query timeouts
  • Bulk batch writes
  • Python / Node.js / Ruby bindings
  • MCP server
  • CLI tools
  • Neo4j APOC import

What's next (ordered by priority):

  • WAL CRC32C integrity checksums (SPA-253)
  • HTTP/SSE transport layer (SPA-231)
  • Multi-label nodes (n:A:B) (SPA-200)
  • LDBC SNB benchmarks (SPA-111)
  • Publish to PyPI / npm

Follow along: github.com/ryaker/SparrowDB

Documentation

Guide
docs/quickstart.md Build your first graph from zero
docs/cypher-reference.md Full Cypher support with examples
docs/bindings.md Rust, Python, Node.js, Ruby API details
docs/mcp-setup.md MCP server and Claude Desktop config
docs/use-cases.md Real-world usage patterns
DEVELOPMENT.md Contributor workflow and architecture

Contributing

Open an issue before submitting a large PR so we can discuss the design first.

git clone https://github.com/ryaker/SparrowDB
cd SparrowDB

cargo build           # build everything
cargo test            # full test suite
cargo test -p sparrowdb  # integration tests only (these are the signal — not unit tests)
cargo clippy          # lints
cargo fmt --check     # format check

cargo build --release --bin sparrowdb    # CLI
cargo build --release --bin sparrowdb-mcp  # MCP server

The workspace is structured so each crate has one job. Adding a Cypher feature typically means touching sparrowdb-cypher (parser + AST) and sparrowdb-execution (executor), with an integration test in crates/sparrowdb/tests/. See DEVELOPMENT.md.

License

MIT — see LICENSE.