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description: FHIR Subscriptions Subscriptions for real-time notifications and event-driven workflows.
---

# Subscriptions

Subscriptions enable real-time notifications and updates between servers and clients. This mechanism allows to respond dynamically to changes in patient data or resource states.\
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By leveraging the subscriptions, developers can specify notification criteria, define delivery channels, and monitor specific events or changes in healthcare data. This push-based approach minimizes the need for constant polling, optimizing resource utilization and improving the timeliness of information dissemination.\
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Aidbox provides several implementations of subscriptions. For enhanced capabilities and ongoing support, please use **Aidbox topic-based subscriptions**. This newer implementation offers improved performance, flexibility, and will continue to be developed to meet future needs.

<table>
  <thead>
    <tr>
      <th width="215">Implementation</th>
      <th>Delivery guarantee</th>
      <th>Channels</th>
      <th>Status</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a href="fhir-topic-based-subscriptions.md">FHIR Topic-Based Subscriptions</a></td>
      <td>At least once</td>
      <td>REST-hook</td>
      <td>Maintained</td>
    </tr>
    <tr>
      <td><a href="aidbox-topic-based-subscriptions">Aidbox topic-based subscriptions</a></td>
      <td>
        <ul>
          <li>At most once</li>
          <li>At least once</li>
        </ul>
      </td>
      <td>
        <ul>
          <li><a href="../../tutorials/subscriptions-tutorials/kafka-aidboxtopicdestination.md">Kafka</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/webhook-aidboxtopicdestination.md">Webhook</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/gcp-pub-sub-aidboxtopicdestination.md">GCP Pub/Sub</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/aidboxtopicsubscription-nats-tutorial.md">NATS</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/rabbitmq-tutorial.md">AMQP (RabbitMQ)</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/aws-eventbridge-aidboxtopicdestination.md">AWS EventBridge</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/aidboxtopicsubscription-sns-tutorial.md">AWS SNS</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/clickhouse-aidboxtopicdestination.md">ClickHouse</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/bigquery-aidboxtopicdestination.md">BigQuery</a></li>
          <li><a href="../../tutorials/subscriptions-tutorials/data-lakehouse-aidboxtopicdestination.md">Data Lakehouse (Databricks)</a></li>
        </ul>
        *additional channels will be implemented by request
      </td>
      <td>Maintained</td>
    </tr>
    <tr>
      <td><a href="./aidbox-subsubscriptions.md">Aidbox SubSubscriptions</a></td>
      <td>At most once</td>
      <td>Webhook</td>
      <td>Deprecated</td>
    </tr>
    <tr>
      <td><a href="../../deprecated/deprecated/zen-related/topic-based-subscriptions/">FHIR topic-based subscriptions (Zen)</a></td>
      <td>At least once</td>
      <td>Webhook</td>
      <td>Deprecated</td>
    </tr>
  </tbody>
</table>