> This page location: Postgres > Extensions & guides > Postgres extensions > plv8
> Full Neon documentation index: https://neon.com/docs/llms.txt

> Summary: plv8, the Postgres extension for writing stored procedures and functions in JavaScript via the V8 engine, is deprecated on Neon and blocked from new installs due to security risks from embedding V8 inside Postgres. Use this page to understand what is blocked (CREATE EXTENSION plv8 returns a deprecation error) and what migration paths exist. Recommended alternatives include rewriting JavaScript-in-SQL logic in plpgsql or moving it to application or worker code outside the database.

# The plv8 extension (deprecated)

JavaScript procedural language for Postgres — no longer available on Neon

**Warning: The plv8 extension is deprecated on Neon.**

**plv8** is deprecated because of **security risks** tied to embedding the V8 JavaScript engine inside Postgres. Neon blocks **`CREATE EXTENSION plv8`** with an explicit deprecation message (same mechanism as other deprecated extensions).

The **`plcoffee`** (CoffeeScript) and **`plls`** (LiveScript) extensions ship with plv8 on Postgres 14, 15, and 16 and run on the same V8 engine, so they're deprecated too. Neon also blocks **`CREATE EXTENSION plcoffee`** and **`CREATE EXTENSION plls`**. Databases that already have them keep working until you drop them.

**If you use plv8 today:** move business logic out of JavaScript-in-SQL—for example rewrite functions in **[plpgsql](https://www.postgresql.org/docs/current/plpgsql.html)** or run JavaScript in your **application** or **worker** layer—and then drop **`plv8`** from databases that still have it. See also [Supported Postgres extensions](https://neon.com/docs/extensions/pg-extensions).

**Alternatives:**

- **SQL and built-in languages:** [plpgsql](https://www.postgresql.org/docs/current/plpgsql.html) (Postgres default procedural language); [plpgsql_check](https://pgxn.org/dist/plpgsql_check/) for optional validation in CI
- **Calling external services:** use **`http`** patterns from app code, queues, or **`pg_net`** / HTTP from Postgres where appropriate for your stack

Upstream project (reference only): [plv8 on GitHub](https://github.com/plv8/plv8).

Neon previously shipped **plv8** so you could write Postgres functions in JavaScript via the V8 engine. That capability is **no longer offered** on new installs.

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## Related docs (Postgres extensions)

- [Extension explorer](https://neon.com/docs/extensions/extension-explorer)
- [anon](https://neon.com/docs/extensions/postgresql-anonymizer)
- [btree_gin](https://neon.com/docs/extensions/btree_gin)
- [btree_gist](https://neon.com/docs/extensions/btree_gist)
- [citext](https://neon.com/docs/extensions/citext)
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- [hstore](https://neon.com/docs/extensions/hstore)
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- [ltree](https://neon.com/docs/extensions/ltree)
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- [neon_utils](https://neon.com/docs/extensions/neon-utils)
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- [pgrowlocks](https://neon.com/docs/extensions/pgrowlocks)
- [pgstattuple](https://neon.com/docs/extensions/pgstattuple)
- [postgis](https://neon.com/docs/extensions/postgis)
- [postgis-related](https://neon.com/docs/extensions/postgis-related-extensions)
- [postgres_fdw](https://neon.com/docs/extensions/postgres_fdw)
- [tablefunc](https://neon.com/docs/extensions/tablefunc)
- [timescaledb](https://neon.com/docs/extensions/timescaledb)
- [unaccent](https://neon.com/docs/extensions/unaccent)
- [uuid-ossp](https://neon.com/docs/extensions/uuid-ossp)
- [wal2json](https://neon.com/docs/extensions/wal2json)
- [xml2](https://neon.com/docs/extensions/xml2)

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