--- title: "Extensions | SurrealDB" description: "Run WebAssembly plugins inside SurrealDB. Write functions in Rust, compile to WASM, and execute with full query engine access. No microservices, no cold starts." url: https://surrealdb.com/surrealdb/extensions --- # Extensions Run custom logic inside SurrealDB. Write functions in Rust, compile to WebAssembly, and execute with full query engine access - no microservices, no cold starts, no network hops. [Get started](https://studio.surrealdb.com/current/instances/deploy) [Read the docs](https://surrealdb.com/docs/learn/extensions) 1. ![Babcock](https://surrealdb.com/assets/static/babcock.lo4rnVg1.svg) 2. ![ING](https://surrealdb.com/assets/static/ing.X3I6S3_V.svg) 3. ![British Airways](https://surrealdb.com/assets/static/british-airways.KEsZiwV-.svg) 4. ![Nvidia](https://surrealdb.com/assets/static/nvidia.DaIEuMil.svg) 5. ![Apple](https://surrealdb.com/assets/static/apple.D5pq4flY.svg) 6. ![SpaceX](https://surrealdb.com/assets/static/spacex.CQJEk-IL.svg) 7. ![Samsung](https://surrealdb.com/assets/static/samsung.CH-vQgnb.svg) 8. ![adidas](https://surrealdb.com/assets/static/adidas.DdTC5qhk.svg) 9. ![Tencent](https://surrealdb.com/assets/static/tencent.paQmLxyy.svg) 10. ![Alibaba](https://surrealdb.com/assets/static/alibaba.B16idgfM.svg) 11. ![PolyAI](https://surrealdb.com/assets/static/poly-ai.c3w_fAg6.svg) 12. ![Later](https://surrealdb.com/assets/static/later.Ds736jFO.svg) 13. ![Verizon](https://surrealdb.com/assets/static/verizon.BI7CajdX.svg) 14. ![Liberty Mutual](https://surrealdb.com/assets/static/liberty-mutual.B7qOU1pd.svg) 15. ![Walmart](https://surrealdb.com/assets/static/walmart.BjDg_Sr8.svg) 16. ![Carrier](https://surrealdb.com/assets/static/carrier.D21gC6NX.svg) 17. ![Saks Fifth Avenue](https://surrealdb.com/assets/static/saks-fifth-avenue.COIDpLSb.svg) 18. ![San Francisco Compute Company](https://surrealdb.com/assets/static/sfcc.B7jlImq4.svg) 19. ![Shield AI](https://surrealdb.com/assets/static/shield-ai.pINZ0KJr.svg) 20. ![Wix](https://surrealdb.com/assets/static/wix.DvHhmoBi.svg) ## Run extensions inside SurrealDB SurrealDB extensions turn it into a programmable data and logic layer - perfect for agentic and AI-heavy workloads. ### [AI-ready by design](https://surrealdb.com/docs/learn/extensions) Call LLMs, embedding models, or GPU inference next to the data and write results back in the same statement. WebAssembly plugins run inference and write results in one atomic operation. SurrealQL Query SELECT *, mod::ml::embed(content) FROM docs LLM Embeddings GPU Atomic write-back Learn more ### [Near-native performance](https://surrealdb.com/docs/surrealdb/extensions/plugins) WebAssembly runs close to the data with WASM sandbox isolation. No filesystem access, no network access - just compute next to the data. WASM Runtime Startup <1ms Latency ~native Isolation Full Filesystem Blocked Network Blocked DB direct Blocked Learn more ### [Fine-grained governance](https://surrealdb.com/docs/learn/security) Secure multi-tenant clusters with least-privilege execution. Each function can have its own permission expression evaluated at call time. Namespace Admin Editor Database Read Write Execute Function PERMISSIONS WHERE $auth.role = 'admin' Evaluated at call time Learn more WASM SANDBOXING ## Isolated by design Each module call creates a fresh WASM instance with its own isolated memory. Modules can only interact with SurrealDB through explicit host functions - no filesystem, no raw network, no direct database access. Data crosses the boundary via serialisation. ![SurrealDB](https://surrealdb.com/assets/static/surrealdb-icon.C3ORaDk9.svg) SurrealDB Engine Query engine Parses and executes SurrealQL Transaction context Shared ACID boundary Host bridge WASM Sandbox WASM Sandbox Module code User-defined Rust compiled to WASM Isolated memory Own Store and Instance per call No filesystem No direct DB No raw network BUILD PIPELINE ## How extensions work Write your functions in Rust, compile into WebAssembly with the SurrealDB CLI, load them into your instance, and call them from SurrealQL. 1 Functions fn return_ten() -> i32 { 10 } fn is_positive(n: i32) -> bool { n >= 0 } Use #[surrealism] to expose functions #[surrealism] fn return_ten() -> i32 { 10 } #[surrealism] fn is_positive(n: i32) -> bool { n >= 0 } surrealism.toml [package] organisation = "surrealdb" name = "demo" version = "1.0.0" 2 Compile with SurrealDB CLI surreal module command Rust code ready to compile to WASM Compiled extension module 3 SurrealDB instance Create file location with DEFINE BUCKET Access the compiled extension module with DEFINE MODULE 4 Access functions inside SurrealDB CREATE person SET num = mod::test::return_ten(); SELECT id, mod::test::is_positive(num) AS is_positive FROM person; ZERO-DOWNTIME UPGRADES ## Hot-load, no downtime Deploy, upgrade, or roll back modules without restarting your instance. In-flight requests continue on the previous version while new requests automatically load the updated module from storage. No forced termination, no cold starts. DEFINE MODULE OVERWRITE ml; Cache invalidation cache.remove(&lookup) - evicts the compiled Runtime In-flight requests Continue on Module v1 Arc stays valid Complete normally Old runtime dropped when done New requests Cache miss → load from bucket Build new Runtime, cache it Module v2 live Zero downtime transition TRANSACTION SAFETY ## Same transaction, same commit When a module calls back into SurrealQL via the host bridge, it runs in the same transaction context as the query that invoked it. Module writes, host callbacks, and the original query all commit or roll back as a single atomic unit. No eventual-consistency bugs. CREATE person SET score = mod::ml::predict(data); Single ACID transaction Query engine Parses SurrealQL, finds mod:: call WASM module executes mod::ml::predict() runs in sandbox Host callback __sr_sql("SELECT * FROM training_data") Runs in same ctx and opt - same transaction Result returned Module returns prediction, query continues COMMIT Query + module writes + host callbacks - one atomic unit GET STARTED ## Start building extensions Run AI and application logic inside SurrealDB with WebAssembly extensions. ![Samsung](https://surrealdb.com/assets/static/4c58b81e7b3c9466.C_Hv0eml.svg)![NVIDIA](https://surrealdb.com/assets/static/nvidia.DaIEuMil.svg)![Apple](https://surrealdb.com/assets/static/f7dc2519e0d212bc.Cn8MYAK7.svg)![Verizon](https://surrealdb.com/assets/static/18b99996c689000f.B5PQ-nI9.svg)![Tencent](https://surrealdb.com/assets/static/401d8346058682c8.DqM87mst.svg) SOC 2 Type 2 GDPR Cyber Essentials Plus ISO 27001 [Read the docs](https://surrealdb.com/docs/learn/extensions) [Start free with SurrealDB](https://studio.surrealdb.com/current/instances/deploy) ```json {"@context":"https://schema.org","@type":"Organization","name":"SurrealDB","url":"https://surrealdb.com","logo":"https://surrealdb.com/assets/static/logo.BG7_TG2b.svg","description":"SurrealDB is the unified data layer for AI. A multi-model database for documents, graphs, vectors, and time-series.","foundingDate":"2022","legalName":"SurrealDB Ltd","identifier":{"@type":"PropertyValue","propertyID":"GB-COH","value":"13615201"},"address":{"@type":"PostalAddress","streetAddress":"3rd Floor, 1 Ashley Road","addressLocality":"Altrincham","addressRegion":"Cheshire","postalCode":"WA14 2DT","addressCountry":"GB"},"contactPoint":[{"@type":"ContactPoint","contactType":"customer support","email":"support@surrealdb.com","url":"https://surrealdb.com/contact","availableLanguage":"English"},{"@type":"ContactPoint","contactType":"sales","email":"info@surrealdb.com","url":"https://surrealdb.com/contact","availableLanguage":"English"},{"@type":"ContactPoint","contactType":"security","email":"security@surrealdb.com","url":"https://surrealdb.com/.well-known/security.txt","availableLanguage":"English"},{"@type":"ContactPoint","contactType":"legal","email":"legal@surrealdb.com","url":"https://surrealdb.com/legal","availableLanguage":"English"}],"hasCertification":[{"@type":"Certification","name":"SOC 2 Type 2"},{"@type":"Certification","name":"GDPR"},{"@type":"Certification","name":"Cyber Essentials Plus"},{"@type":"Certification","name":"ISO 27001"}],"owns":[{"@type":"SoftwareApplication","name":"SurrealDB","url":"https://surrealdb.com/surrealdb"},{"@type":"SoftwareApplication","name":"Agent Memory","url":"https://surrealdb.com/agent-memory"}],"knowsAbout":["multi-model databases","document databases","graph databases","vector search","time-series databases","SurrealQL","Agent Memory","real-time databases","embedded databases","context layer","graph ontology","distributed database","knowledge graphs","distributed transaction protocols","highly-scalable databases"],"sameAs":["https://www.wikidata.org/wiki/Q124316308","https://github.com/surrealdb/surrealdb","https://twitter.com/surrealdb","https://www.youtube.com/@surrealdb","https://www.linkedin.com/company/surrealdb","https://discord.gg/surrealdb","https://www.reddit.com/r/surrealdb","https://www.instagram.com/surrealdb","https://medium.com/surrealdb","https://dev.to/surrealdb"]} ``` ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://surrealdb.com"},{"@type":"ListItem","position":2,"name":"SurrealDB","item":"https://surrealdb.com/surrealdb"},{"@type":"ListItem","position":3,"name":"Extensions","item":"https://surrealdb.com/surrealdb/extensions"}]} ```