# Apache Pulsar vs NATS

**Leader by vioscaleAI score:** NATS

| Attribute | Apache Pulsar | NATS |
|---|---|---|
| **vioscaleAI score** | 60.2 (38% (low)) | 67.8 (58% (medium)) |
| activity.commits_last_30d | 100 | 100 |
| adoption.dependent_repos | 316 | 24,884 |
| adoption.github_stars | 15,343 | 20,867 |
| adoption.package_downloads_weekly | - | 1,353,667 |
| content.faq | `[{"answer":"A distributed messaging system built for cloud deployments that enables applications to reliably publish and consume messages—either individually or as continuous streams—with sub-10-millisecond latency, supporting millions of independent topics and large-scale streaming workloads. It is indexed under Message Queues.","source":"https://pulsar.apache.org","question":"What is Apache Pulsar?","confidence":0.6},{"answer":"Apache Pulsar is open source, so it can be self-hosted and used at no licence cost. It is released under the Apache-2.0 licence. Pricing changes often, so verify at source before relying on it.","source":"https://pulsar.apache.org","question":"Is Apache Pulsar free to use?","confidence":0.6},{"answer":"Apache Pulsar supports a command-line interface. Platforms we have not confirmed are simply not listed here rather than ruled out.","source":"https://pulsar.apache.org","question":"What platforms does Apache Pulsar support?","confidence":0.6},{"answer":"Yes. Apache Pulsar can be deployed cloud / SaaS and self-hosted, so it does not have to run on the vendor's infrastructure.","source":"https://pulsar.apache.org","question":"Can Apache Pulsar be self-hosted?","confidence":0.6},{"answer":"We have confirmed 27 integrations for Apache Pulsar, including Kafka, RabbitMQ, MongoDB, Cassandra, Elasticsearch, HBase, HDFS and InfluxDB, plus 19 more. This is what we could verify from public sources, so the vendor may support others we have not indexed.","source":"https://pulsar.apache.org","question":"What does Apache Pulsar integrate with?","confidence":0.6},{"answer":"Yes. Apache Pulsar is published under the Apache-2.0 licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.","source":"https://github.com/apache/pulsar","question":"Is Apache Pulsar open source?","confidence":0.95}]` | `[{"answer":"NATS enables components of a distributed software system to send messages to each other. It is an open-source project maintained by the Cloud Native Computing Foundation and can be deployed across cloud environments, on-site servers, edge computing devices, and embedded systems. It is indexed under Message Queues.","source":"https://nats.io","question":"What is NATS?","confidence":0.6},{"answer":"NATS is open source, so it can be self-hosted and used at no licence cost. It is released under the Apache-2.0 licence. Pricing changes often, so verify at source before relying on it.","source":"https://nats.io","question":"Is NATS free to use?","confidence":0.6},{"answer":"NATS supports a command-line interface. Platforms we have not confirmed are simply not listed here rather than ruled out.","source":"https://nats.io","question":"What platforms does NATS support?","confidence":0.6},{"answer":"Yes. NATS can be deployed cloud / SaaS, on-premise and self-hosted, so it does not have to run on the vendor's infrastructure.","source":"https://nats.io","question":"Can NATS be self-hosted?","confidence":0.6},{"answer":"We have independently confirmed GDPR for NATS. Certifications we do not list are ones we have not been able to verify from public sources, which is not the same as NATS not holding them. Always confirm compliance directly before you rely on it.","source":"https://nats.io/privacy","question":"What security certifications does NATS have?","confidence":0.7},{"answer":"Yes. NATS is published under the Apache-2.0 licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.","source":"https://github.com/nats-io/nats-server","question":"Is NATS open source?","confidence":0.95}]` |
| deployment.options | `{"cloud":true,"self_hosted":true}` | `{"cloud":true,"self_hosted":true}` |
| description.long | A message broker supporting both pub-sub and queue-based messaging patterns. It provides durable storage with strong ordering guarantees, horizontally scales to millions of topics and messages per second, and supports geo-replication for distributed deployments. | An open-source, lightweight messaging platform that combines pub/sub, request/reply, and persistent streaming capabilities into a single system for building high-performance distributed applications. |
| features.capabilities | `{"hosting":"both","ordering":"per_partition","paradigm":"pubsub","protocol":"pulsar://","message_replay":true,"persistent_log":true,"consumer_groups":true,"geo_replication":true,"kafka_compatible":true,"stream_processing":true,"delivery_guarantee":"exactly_once","horizontal_scaling":true}` | `{"hosting":"self","paradigm":"pubsub","message_replay":true,"persistent_log":true,"consumer_groups":true,"geo_replication":true,"managed_offering":true,"horizontal_scaling":true}` |
| integrations.count | 35 | 12 |
| integrations.list | `[{"name":"Kafka"},{"name":"RabbitMQ"},{"name":"MongoDB"},{"name":"Cassandra"},{"name":"Elasticsearch"},{"name":"HBase"},{"name":"HDFS"},{"name":"InfluxDB"},{"name":"Redis"},{"name":"Solr"},{"name":"DynamoDB"},{"name":"Kinesis"},{"name":"Azure Data Explorer"},{"name":"ClickHouse"},{"name":"PostgreSQL"},{"name":"MariaDB"},{"name":"SQLite"},{"name":"Debezium MySQL"},{"name":"Debezium PostgreSQL"},{"name":"Debezium MongoDB"},{"name":"Debezium Oracle"},{"name":"Debezium Microsoft SQL Server"},{"name":"Canal"},{"name":"Aerospike"},{"name":"Alluxio"},{"name":"NSQ"},{"name":"Netty"},{"name":"HTTP"},{"name":"File"},{"name":"Kafka Connect Adaptor","native":true,"direction":"bidirectional"},{"name":"MySQL","native":true}]` | `[{"name":"Stripe","category":"payments"},{"name":"Apache Kafka","category":"messaging"},{"name":"Apache Spark","category":"data_processing"},{"name":"Apache Flink","category":"stream_processing"},{"name":"RabbitMQ","category":"messaging"},{"name":"Prometheus","category":"monitoring"},{"name":"RisingWave","category":"stream_database"},{"name":"Caddy","category":"web_server"},{"name":"Deepstream","category":"messaging"},{"name":"Synadia","category":"platform_service"},{"name":"Gatling","category":"load_testing"},{"name":"Yii","category":"web_framework"}]` |
| language.primary | Java | Go |
| license.spdx | Apache-2.0 | Apache-2.0 |
| market.availability | - | `{"primaryMarkets":[],"availabilityScope":"global","availableCountries":[],"notAvailableCountries":[]}` |
| platform.support | `{"cli":true,"mac":true,"web":true,"linux":true,"windows":true}` | `{"cli":true,"web":true}` |
| pricing | `{"type":"open_source","sourceUrl":"https://pulsar.apache.org","retrievedAt":"2026-10-14T22:35:49.214Z"}` | `{"type":"open_source","freeTier":true,"sourceUrl":"https://nats.io","retrievedAt":"2026-10-13T15:14:05.510Z"}` |
| pricing.free_tier | yes | yes |
| pricing.model | open_source | open_source |
| pricing.price_level | free | free |
| release.cadence_days | 3 | 1 |
| release.history | `[{"url":"https://github.com/apache/pulsar/releases/tag/v5.0.0","date":"2026-10-05T19:22:24Z","type":"stable","version":"v5.0.0"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.2.5","date":"2026-10-05T19:23:03Z","type":"stable","version":"v4.2.5"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.14","date":"2026-10-05T19:23:29Z","type":"stable","version":"v4.0.14"},{"url":"https://github.com/apache/pulsar/releases/tag/v5.0.0-M2","date":"2026-09-16T23:33:14Z","type":"prerelease","version":"v5.0.0-M2"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.2.4","date":"2026-08-03T09:19:30Z","type":"stable","version":"v4.2.4"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.13","date":"2026-08-03T09:19:06Z","type":"stable","version":"v4.0.13"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.2.3","date":"2026-07-06T08:46:50Z","type":"stable","version":"v4.2.3"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.12","date":"2026-07-06T08:46:18Z","type":"stable","version":"v4.0.12"},{"url":"https://github.com/apache/pulsar/releases/tag/v5.0.0-M1","date":"2026-06-23T14:11:26Z","type":"prerelease","version":"v5.0.0-M1"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.2.2","date":"2026-06-08T18:16:45Z","type":"stable","version":"v4.2.2"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.11","date":"2026-06-08T18:16:01Z","type":"stable","version":"v4.0.11"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.2.1","date":"2026-04-27T13:04:33Z","type":"stable","version":"v4.2.1"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.10","date":"2026-04-27T13:04:17Z","type":"stable","version":"v4.0.10"},{"url":"https://github.com/apache/pulsar/releases/tag/v3.0.17","date":"2026-04-27T13:03:58Z","type":"stable","version":"v3.0.17"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.2.0","date":"2026-03-31T21:12:26Z","type":"stable","version":"v4.2.0"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.1.3","date":"2026-02-19T19:48:49Z","type":"stable","version":"v4.1.3"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.9","date":"2026-02-19T19:48:13Z","type":"stable","version":"v4.0.9"},{"url":"https://github.com/apache/pulsar/releases/tag/v3.0.16","date":"2026-02-16T09:24:53Z","type":"stable","version":"v3.0.16"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.1.2","date":"2025-11-17T07:58:34Z","type":"stable","version":"v4.1.2"},{"url":"https://github.com/apache/pulsar/releases/tag/v4.0.8","date":"2025-11-17T07:58:06Z","type":"stable","version":"v4.0.8"}]` | `[{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.1","date":"2026-10-09T08:40:47Z","type":"stable","version":"v2.15.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.8","date":"2026-10-09T08:40:31Z","type":"stable","version":"v2.14.8"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.1-RC.2","date":"2026-10-06T10:57:55Z","type":"prerelease","version":"v2.15.1-RC.2"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.8-RC.2","date":"2026-10-06T10:56:59Z","type":"prerelease","version":"v2.14.8-RC.2"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.1-RC.1","date":"2026-09-28T17:12:45Z","type":"prerelease","version":"v2.15.1-RC.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.8-RC.1","date":"2026-09-28T17:12:29Z","type":"prerelease","version":"v2.14.8-RC.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.0","date":"2026-09-17T13:30:47Z","type":"stable","version":"v2.15.0"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.0-RC.2","date":"2026-09-15T16:27:50Z","type":"prerelease","version":"v2.15.0-RC.2"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.7","date":"2026-09-15T15:10:36Z","type":"stable","version":"v2.14.7"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.7-RC.2","date":"2026-09-14T15:48:51Z","type":"prerelease","version":"v2.14.7-RC.2"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.7-RC.1","date":"2026-09-10T16:05:31Z","type":"prerelease","version":"v2.14.7-RC.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.0-RC.1","date":"2026-09-07T16:35:00Z","type":"prerelease","version":"v2.15.0-RC.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.6","date":"2026-08-27T15:21:20Z","type":"stable","version":"v2.14.6"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.6-RC.2","date":"2026-08-26T17:01:24Z","type":"prerelease","version":"v2.14.6-RC.2"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.6-RC.1","date":"2026-08-25T16:47:43Z","type":"prerelease","version":"v2.14.6-RC.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.15.0-preview.1","date":"2026-08-24T13:33:40Z","type":"prerelease","version":"v2.15.0-preview.1"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.5","date":"2026-08-12T15:31:27Z","type":"stable","version":"v2.14.5"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.15","date":"2026-08-12T15:30:42Z","type":"stable","version":"v2.12.15"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.14.4","date":"2026-07-30T13:57:21Z","type":"stable","version":"v2.14.4"},{"url":"https://github.com/nats-io/nats-server/releases/tag/v2.12.14","date":"2026-07-30T13:56:36Z","type":"stable","version":"v2.12.14"}]` |
| security.disclosure_policy | - | yes |
| security.gdpr | - | yes |
| security.scorecard | 7.1 | 7.4 |
| security.trust_center | https://pulsar.apache.org/docs/5.0.x/security-athenz/ | - |
| security.vulnerabilities | `{"count":0,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=maven&package_name=org.apache.pulsar%3Apulsar-client-admin&per_page=100","last_12m":0,"max_severity":null}` | `{"count":29,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=go&package_name=github.com%2Fnats-io%2Fnats-server%2Fv2&per_page=100","last_12m":14,"max_severity":"CRITICAL"}` |

## Capabilities (Message Queues)

| Capability | Apache Pulsar | NATS |
|---|:--:|:--:|
| **Core** |  |  |
| Messaging paradigm | Pub/sub | Pub/sub |
| **Correctness** |  |  |
| Delivery guarantee | Exactly-once | - |
| Ordering guarantee | Per-partition | - |
| **Durability** |  |  |
| Durable replayable log | ✓ | ✓ |
| Message replay / rewind | ✓ | ✓ |
| **Interop** |  |  |
| Wire protocol | pulsar:// | - |
| Kafka-protocol compatible | ✓ | - |
| **Scale** |  |  |
| Partitioned horizontal scaling | ✓ | ✓ |
| Geo / cross-region replication | ✓ | ✓ |
| **Consumption** |  |  |
| Consumer groups / competing consumers | ✓ | ✓ |
| Dead-letter queue | - | - |
| **Deployment** |  |  |
| Managed cloud offering exists | - | ✓ |
| Hosting | Cloud + self-hosted | Self-hosted only |
| **Processing** |  |  |
| Built-in stream processing | ✓ | - |

*Source: vioscaleAI. Generated 2026-10-16T20:14:31.638Z. "-" = undocumented, not absent.*