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Datost connects to ClickHouse so your team can ask event, product, and OLAP questions in Slack and get answers backed by real columnar data. It’s a good fit for high-volume event streams, product analytics tables, and ClickHouse Cloud clusters.

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Prerequisites

Before connecting, gather the following from your ClickHouse cluster:
  • Host — e.g. your-cluster.clickhouse.cloud or an IP address
  • HTTP port — 8123 for HTTP, 8443 for HTTPS (ClickHouse Cloud defaults to HTTPS on 8443)
  • Protocol — HTTP or HTTPS
  • Username — defaults to default
  • Password
  • Database (optional) — leave empty to expose all non-system databases
Datost uses the official @clickhouse/client package over the HTTP interface. The native TCP protocol is not supported.

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Connect in the admin panel

1

Open Data Sources

In the Datost web app, go to Settings → Data Sources and click Add data source.
2

Choose ClickHouse

Select ClickHouse from the provider grid.
3

Paste a connection URL or fill fields manually

Paste a ClickHouse Cloud curl command or connection URL to auto-fill host, port, protocol, username, and password — or enter them manually. Supported shapes include clickhouse://user:pass@host:port/db, bare https://host.clickhouse.cloud:8443, and the curl --user 'user:pass' https://host:port snippet from the ClickHouse Cloud connect dialog.
4

Whitelist the Datost egress IP

If your cluster restricts traffic, add the egress IP shown in the modal to your ClickHouse IP allowlist.
5

Test and save

Click Test connection. Datost runs SELECT version() to confirm reachability and returns the server version. Save to finish.

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Permissions required

The connecting user needs:
  • SELECT on the databases and tables you want Datost to query.
  • SELECT on system.tables and system.columns for schema introspection (used for table listing and column metadata).
Read-only users work well. Datost does not issue writes during normal operation.
If you provide a specific database, Datost scopes schema discovery to that database. Leaving it blank exposes every database except system, INFORMATION_SCHEMA, and information_schema.

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Limitations

Large result sets are capped. Queries run with max_result_rows (default 1000) and result_overflow_mode = 'break', so ClickHouse stops streaming once the cap is hit and the response is marked as truncated.
  • HTTP only. The native TCP protocol isn’t supported — use the HTTP/HTTPS interface (ports 8123/8443).
  • Client caching. Datost caches up to 50 ClickHouse clients per process with a 30-minute idle TTL; connections refresh automatically when credentials change.
  • Statement termination. Trailing semicolons are stripped before the query is sent.
  • Views vs. tables. Engines containing View are surfaced as views; everything else is treated as a table.

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Troubleshooting

  • Connection test fails with a network error — verify the port matches your protocol (8123 for HTTP, 8443 for HTTPS) and that the Datost egress IP is whitelisted.
  • Authentication error — confirm the username (ClickHouse Cloud defaults to default) and that the password has no leading/trailing whitespace from the paste.
  • Missing tables — check that the user has SELECT on system.tables and system.columns, and that you didn’t scope the connection to a database that doesn’t contain them.