--- title: "Choose a service" slug: "dev-start-choose-a-service" updated: 2026-10-30T18:18:46Z published: 2026-10-30T18:18:46Z canonical: "docs.vastdata.com/dev-start-choose-a-service" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt > Use this file to discover all available pages before exploring further. # Choose a service *Applies to VAST Cluster 5.5.* Find what you want to do under the service that does it, then start with that service's overview and quickstart. ## ![](https://cdn.us.document360.io/89b91113-5dc6-49db-86ec-57b16dc8ce56/Images/Documentation/icon-database.svg?sv=2026-02-06&spr=https&st=2026-11-08T08%3A55%3A28Z&se=2026-11-08T09%3A55%3A28Z&sr=c&sp=r&sig=ShiUmy%2BSsBds8CAxrKUYgAhhhfdrRUzTwsCBoyrfBuc%3D) VAST DataBase [Overview](/develop/docs/dev-database-overview) · [Quickstart](/develop/docs/dev-database-quickstart) | I want to … | Start with | | --- | --- | | Store tables and query them with SQL or from Python, with transactions and row-level updates and deletes | [Overview](/develop/docs/dev-database-overview), [quickstart](/develop/docs/dev-database-quickstart) | | Run several engines (Python, Trino, Spark) on one copy of the same tables | [Overview](/develop/docs/dev-database-overview#how-you-access-it), [quickstart](/develop/docs/dev-database-quickstart) | ## ![](https://cdn.us.document360.io/89b91113-5dc6-49db-86ec-57b16dc8ce56/Images/Documentation/icon-vector-search.svg?sv=2026-02-06&spr=https&st=2026-11-08T08%3A55%3A28Z&se=2026-11-08T09%3A55%3A28Z&sr=c&sp=r&sig=ShiUmy%2BSsBds8CAxrKUYgAhhhfdrRUzTwsCBoyrfBuc%3D) VAST Vector Search [Overview](/develop/docs/dev-vector-search-overview) · [Quickstart](/develop/docs/dev-vector-search-quickstart) | I want to … | Start with | | --- | --- | | Store embeddings and run nearest-neighbour search, with SQL filters | [Overview](/develop/docs/dev-vector-search-overview), [quickstart](/develop/docs/dev-vector-search-quickstart) | | Retrieve document chunks for RAG, returning only chunks the user may read | [RAG retrieval](/develop/docs/dev-vector-search-guides-rag-retrieval), [quickstart](/develop/docs/dev-vector-search-quickstart) | ## ![](https://cdn.us.document360.io/89b91113-5dc6-49db-86ec-57b16dc8ce56/Images/Documentation/icon-event-broker.svg?sv=2026-02-06&spr=https&st=2026-11-08T08%3A55%3A28Z&se=2026-11-08T09%3A55%3A28Z&sr=c&sp=r&sig=ShiUmy%2BSsBds8CAxrKUYgAhhhfdrRUzTwsCBoyrfBuc%3D) VAST Event Broker [Overview](/develop/docs/dev-event-broker-overview) · [Quickstart](/develop/docs/dev-event-broker-quickstart) | I want to … | Start with | | --- | --- | | Produce and consume streaming events with Kafka clients | [Overview](/develop/docs/dev-event-broker-overview), [quickstart](/develop/docs/dev-event-broker-quickstart) | | Query a stream's events with SQL, without a connector job that copies them into tables | [Query topics as tables](/develop/docs/dev-event-broker-guides-querying-topics), [quickstart](/develop/docs/dev-event-broker-quickstart) | | Parse JSON events into typed columns of a table as they arrive | [Blob expansion](/develop/docs/dev-event-broker-guides-blob-expansion) | | Get a Kafka event each time an object in an S3 bucket is created, tagged or deleted, for your own consumer | [S3 bucket events](/develop/docs/dev-event-broker-guides-s3-bucket-events) | ## ![](https://cdn.us.document360.io/89b91113-5dc6-49db-86ec-57b16dc8ce56/Images/Documentation/icon-dataengine.svg?sv=2026-02-06&spr=https&st=2026-11-08T08%3A55%3A28Z&se=2026-11-08T09%3A55%3A28Z&sr=c&sp=r&sig=ShiUmy%2BSsBds8CAxrKUYgAhhhfdrRUzTwsCBoyrfBuc%3D) VAST DataEngine [Overview](/develop/docs/dev-dataengine-overview) · [Quickstart](/develop/docs/dev-dataengine-quickstart) | I want to … | Start with | | --- | --- | | Run Python code each time an object or file is created or deleted, or on a schedule | [Overview](/develop/docs/dev-dataengine-overview), [quickstart](/develop/docs/dev-dataengine-quickstart) | | Compute embeddings, or write rows to a table, as files and objects arrive | [VAST DataBase and Vector Search from a function](/develop/docs/dev-dataengine-integrations-vast-database-and-vector-search) | ## ![](https://cdn.us.document360.io/89b91113-5dc6-49db-86ec-57b16dc8ce56/Images/Documentation/icon-datastore.svg?sv=2026-02-06&spr=https&st=2026-11-08T08%3A55%3A28Z&se=2026-11-08T09%3A55%3A28Z&sr=c&sp=r&sig=ShiUmy%2BSsBds8CAxrKUYgAhhhfdrRUzTwsCBoyrfBuc%3D) VAST DataStore [Overview](/develop/docs/dev-datastore-overview) · [Quickstart](/develop/docs/dev-datastore-quickstart) | I want to … | Start with | | --- | --- | | Read and write objects over S3 with boto3, the AWS CLI, s3fs or PyArrow | [Overview](/develop/docs/dev-datastore-overview), [quickstart](/develop/docs/dev-datastore-quickstart) | | Mount files over NFS for an application, or share the same data over S3 and NFS | [NFS for applications](/develop/docs/dev-datastore-guides-nfs-for-applications), [multiprotocol access](/develop/docs/dev-datastore-guides-multiprotocol) | ## ![](https://cdn.us.document360.io/89b91113-5dc6-49db-86ec-57b16dc8ce56/Images/Documentation/icon-catalog.svg?sv=2026-02-06&spr=https&st=2026-11-08T08%3A55%3A28Z&se=2026-11-08T09%3A55%3A28Z&sr=c&sp=r&sig=ShiUmy%2BSsBds8CAxrKUYgAhhhfdrRUzTwsCBoyrfBuc%3D) VAST Catalog [Overview](/develop/docs/dev-catalog-overview) · [Quickstart](/develop/docs/dev-catalog-quickstart) | I want to … | Start with | | --- | --- | | Find files and objects by name, size, age, owner or S3 tag without walking directories | [Overview](/develop/docs/dev-catalog-overview), [quickstart](/develop/docs/dev-catalog-quickstart) | | See what changed in a namespace between two points in time | [Snapshots and change detection](/develop/docs/dev-catalog-guides-snapshots-and-change-detection) | | Find out who read, wrote or deleted a path, and whether it succeeded (audit log) | [Query the audit log](/develop/docs/dev-catalog-guides-audit-log) | ## Across services | I want to … | Start with | | --- | --- | | Create views, policies, keys, tables or topics from CI | [Automation tools compared](/develop/docs/dev-database-reference-automation-tools) | Some things to know before you choose: - **Search runs through the VAST Query Engine.** The Trino and Spark connectors don't support vector index-based search ([VAST Vector Search overview](/develop/docs/dev-vector-search-overview#use-cases-and-considerations)). - **DataEngine is for per-event or per-batch work, not for SQL over large tables.** For that, use the VAST Query Engine, Trino or Spark ([VAST DataEngine overview](/develop/docs/dev-dataengine-overview#use-cases-and-considerations)). - **You don't need DataEngine just to get S3 bucket notifications into a Kafka topic** for your own consumers ([VAST DataEngine overview](/develop/docs/dev-dataengine-overview#how-it-fits-with-vast-database-event-broker-and-vector-search)). - **The Catalog lags the file system.** It's as fresh as its last indexed snapshot, so don't use it for anything that must see a file the moment it's written ([VAST Catalog overview](/develop/docs/dev-catalog-overview#use-cases-and-considerations)). ## Combining services Many applications use more than one service: for example, objects landing in DataStore trigger a DataEngine function that writes to a VAST DataBase table. [End-to-end patterns](/develop/docs/dev-start-end-to-end-patterns) outlines the common combinations and links each step to the page that covers it.