---
warning: DO NOT CHANGE THIS MANUALLY, THIS IS GENERATED BY https://github.com/duckdb/community-extensions repository, check README there
title: nats_js
excerpt: |
  DuckDB Community Extensions
  Query NATS JetStream message streams directly with SQL

extension:
  name: nats_js
  description: Query NATS JetStream message streams directly with SQL
  version: 0.4.0
  language: C++
  build: cmake
  license: MIT
  excluded_platforms: "linux_amd64_musl;windows_amd64_mingw;wasm_mvp;wasm_eh;wasm_threads"
  maintainers:
    - brannn

repo:
  github: brannn/duckdb-nats-jetstream
  ref: e3a8038757a187f2df1afcec4b687ff0587c26f5
  variegata: 6979bb32de0c215f5f6d5c5dc71ff6ea8b4fdbb6

docs:
  hello_world: |
    -- Read messages from a stream (the server defaults to nats://localhost:4222)
    SELECT subject, seq, ts_nats, payload
    FROM nats_scan('telemetry', start_seq := 1, end_seq := 100);

    -- Filter subjects with NATS wildcards and extract JSON fields, including nested ones
    SELECT seq, device_id, location_zone, kw
    FROM nats_scan('telemetry',
        subject := 'telemetry.*.power.>',
        json_extract := ['device_id', 'location.zone', 'kw']
    );

    -- Extract Protocol Buffers fields with native types
    SELECT device_id, location_zone, metrics_kw
    FROM nats_scan('telemetry_proto',
        proto_file := 'telemetry.proto',
        proto_message := 'Telemetry',
        proto_extract := ['device_id', 'location.zone', 'metrics.kw']
    );

  extended_description: |
    The nats_js extension reads the messages stored in NATS JetStream streams with SQL. It creates no consumers.

    Features:
    - Subject filters with NATS wildcards, applied by the server
    - Sequence ranges (start_seq, end_seq) and time ranges (start_time, end_time), also from WHERE clauses
    - Batched reads on nats-server 2.11 and later
    - Message headers as a MAP(VARCHAR, VARCHAR[]) column
    - JSON field extraction with dot paths for nested fields
    - Protocol Buffers decoding from a .proto file at query time, with native DuckDB types
    - Authentication and TLS through DuckDB secrets of type nats
    - Streams with or without allow_direct

    Documentation: https://github.com/brannn/duckdb-nats-jetstream

extension_star_count: 22
extension_star_count_pretty: 22
extension_download_count: 632
extension_download_count_pretty: 632
image: '/images/community_extensions/social_preview/preview_community_extension_nats_js.png'
layout: community_extension_doc
---
### Compatibility Matrix

This table covers all DuckDB releases that have not reached [end-of-life](https://duckdb.org/release_calendar), including LTS releases, and shows the 2 most recent patch releases of each. Older patch releases are not listed, but the extension may be available for them as well.

<div class="extension_compatibility_table"></div>

| Platform | 1.4.4 | 1.4.5 | 1.5.5 | 1.5.6 | 2.0.0 |
| :--- | :---: | :---: | :---: | :---: | :---: |
| Linux AMD64 | ✅ | ❌ | ❌ | ❌ | ✅ |
| Linux ARM64 | ✅ | ❌ | ❌ | ❌ | ✅ |
| macOS AMD64 | ✅ | ❌ | ❌ | ❌ | ✅ |
| macOS ARM64 | ✅ | ❌ | ❌ | ❌ | ✅ |
| Windows AMD64 | ✅ | ❌ | ❌ | ❌ | ✅ |
| Windows ARM64 | ❌ | ❌ | ❌ | ❌ | ❌ |
| WebAssembly | ✅ | ❌ | ❌ | ❌ | ❌ |

### Installing and Loading
```sql
INSTALL {{ page.extension.name }} FROM community;
LOAD {{ page.extension.name }};
```

{% if page.docs.hello_world %}
### Example
```sql
{{ page.docs.hello_world }}```
{% endif %}

{% if page.docs.extended_description %}
### About {{ page.extension.name }}
{{ page.docs.extended_description }}
{% endif %}
### Added Functions

<div class="extension_functions_table"></div>

| function_name | function_type | description | comment | examples |
|---------------|---------------|-------------|---------|----------|
| nats_scan     | table         | NULL        | NULL    |          |

### Overloaded Functions

<div class="extension_functions_table"></div>

This extension does not add any function overloads.

### Added Types

<div class="extension_types_table"></div>

This extension does not add any types.

### Added Settings

<div class="extension_settings_table"></div>

|      name      |                       description                       | input_type | scope  | aliases | typed_value |
|----------------|---------------------------------------------------------|------------|--------|---------|-------------|
| temp_directory | Set the directory to which temporary files are written. | VARCHAR    | GLOBAL | []      | post.db.tmp |