sql.js
SQLite compiled to WebAssembly, runnable in browsers and Node.js without native bindings. Provides a full SQLite engine entirely in JavaScript/WASM — supports the complete SQL dialect, transactions, and in-memory or file-based databases (via Uint8Array export/import). Powers in-browser SQL tools and agent environments that can't use native modules.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Runs entirely in browser sandbox — no server-side risk. SQL injection is still possible if user input is concatenated into queries — always use prepared statements. WASM binary should be verified via integrity hash.
⚡ Reliability
Best When
You need full SQLite in the browser or in a Node.js environment that can't use native modules — in-browser data analytics, offline agents, or sandboxed execution environments.
Avoid When
You're running server-side Node.js where native bindings work — use better-sqlite3 for 10-100x better performance.
Use Cases
- • Run SQL queries against structured data in browser-based agent tools without a backend database server
- • Load SQLite database files (.db) in the browser for client-side data exploration agents
- • Execute complex SQL analytics (JOINs, aggregations, window functions) in-browser without network round trips
- • Build offline-capable agents that store and query structured data entirely client-side using SQLite
- • Test SQL query logic in Node.js without native SQLite bindings (useful in CI environments with restricted native builds)
Not For
- • Production server-side SQLite — better-sqlite3 is 10-100x faster for Node.js server use due to native bindings
- • Persistent browser storage — sql.js data lives in memory and must be manually exported to IndexedDB/localStorage for persistence
- • Large datasets — WASM SQLite has higher memory overhead than native; large tables may hit browser memory limits
Interface
Authentication
Local WASM library — no authentication required. Data access controlled by JavaScript execution context.
Pricing
MIT license. SQLite itself is public domain. WASM compilation by sql-js contributors.
Agent Metadata
Known Gotchas
- ⚠ Database is entirely in-memory by default — must call db.export() to get Uint8Array and persist to IndexedDB/localStorage/file manually; data is lost on page refresh
- ⚠ WASM initialization is async — must await initSqlJs({ locateFile: ... }) before creating any DB instance; synchronous access before init throws
- ⚠ Result rows are returned as arrays of values, not objects — use stmt.getAsObject() or map column names manually for named-field access
- ⚠ WASM bundle is ~1MB — lazy load sql.js and consider a CDN for browser agents to avoid blocking initial load
- ⚠ sql.js uses SQLite's WAL mode limitations in WASM — concurrent access from multiple browser tabs is not supported
- ⚠ sql-js does not auto-update with SQLite releases — check which SQLite version is bundled and verify it has required features (e.g., JSON1 extension support)
Alternatives
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Scores are editorial opinions as of 2026-03-06.