ClickHouse Node.js Client — Coding

Reference: https://clickhouse.com/docs/integrations/javascript

⚠️ Node.js runtime only. This skill covers the
@clickhouse/client
package running in a Node.js runtime exclusively — including Next.js Node runtime API routes, React Server Components, Server Actions, and standard Node.js processes. Do not apply this skill to browser client components, Web Workers, Next.js Edge runtime, Cloudflare Workers, or any usage of
@clickhouse/client-web
. For browser/edge environments, the correct package is
@clickhouse/client-web
.

How to Use This Skill

Match the user's intent to a row in the Task Index below and read the corresponding reference file before writing code. After reading it, scan any Answer checklist in that reference and make sure the final answer covers each relevant item; those checklists capture details users usually need but are easy to omit in short answers.
Always import from
@clickhouse/client
(never
```
@clickhouse/client-web
```
) and create a client with
```
createClient({ url })
```
or rely on supported defaults when appropriate. Close it with
```
await client.close()
```
preferably when it's no longer needed or during graceful shutdown for global resources.
Prefer
JSONEachRow
for typical row inserts/selects unless the user has already chosen another format or is streaming raw bytes (CSV / TSV / Parquet — see
```
examples/node/performance/
```
). Note on
clickhouse_settings
: settings passed to
```
createClient
```
are defaults for every request; they can be overridden per-call by passing
```
clickhouse_settings
```
directly to
```
insert()
```
,
```
query()
```
, or
```
command()
```
. Always mention this when the user configures settings at the client level.
Always use
query_params
for user-supplied values — never template- literal-interpolate them into SQL. See
```
reference/query-parameters.md
```
. When answering a parameter-binding question, your response must explicitly name template-literal interpolation as a "SQL injection risk" — even when the user only asked about syntax and did not raise security. The literal phrase "SQL injection" needs to appear; this is the most common mistake from PostgreSQL/MySQL users and the security framing is part of the correct answer, not an optional aside.
Pick the right method for the job:
- ```
client.insert()
```
  — write rows.
- ```
client.query()
```
  +
```
resultSet.json()
```
  /
```
.text()
```
  /
```
.stream()
```
  — read rows that return data.
- ```
client.command()
```
  — DDL and other statements that don't return rows (
```
CREATE
```
  ,
```
DROP
```
  ,
```
TRUNCATE
```
  ,
```
ALTER
```
  ,
```
SET
```
  in a session, etc.).
- ```
client.exec()
```
  — when you need the raw response stream of an arbitrary statement (rare in coding scenarios).
- ```
client.ping()
```
  — health check; returns
```
{ success, error? }
```
  , never throws on connection failure.
Note version constraints when relevant. Examples:
- ```
pathname
```
  config option: client
```
>= 1.0.0
```
  .
- ```
BigInt
```
  values in
```
query_params
```
  : client
```
>= 1.15.0
```
  .
- ```
TupleParam
```
  and JS
```
Map
```
  in
```
query_params
```
  : client
```
>= 1.9.0
```
  .
- Configurable
```
json.parse
```
  /
```
json.stringify
```
  : client
```
>= 1.14.0
```
  .
- ```
Time
```
  /
```
Time64
```
  data types: ClickHouse server
```
>= 25.6
```
  .
- ```
Dynamic
```
  /
```
Variant
```
  / new
```
JSON
```
  types: ClickHouse server
```
>= 24.1
```
  /
```
24.5
```
  /
```
24.8
```
  (no longer experimental since
```
25.3
```
  ).

Task Index

Identify the user's task and read the matching reference file.

Task	Triggers / symptoms	Reference file
Configure / connect the client	Building a `createClient` call, URL parameters, `clickhouse_settings` , default format, custom HTTP headers	`reference/client-configuration.md`
Ping the server	Health checks, readiness probes, "is ClickHouse up?"	`reference/ping.md`
Choose an insert format	"Which format should I use to insert?", JSON vs raw, `JSONEachRow` vs `JSON` vs `JSONObjectEachRow`	`reference/insert-formats.md`
Insert into a subset of columns / different database	`insert({ columns })` , excluding columns, ephemeral columns, cross-DB inserts	`reference/insert-columns.md`
Insert values, expressions, dates, decimals	`INSERT … VALUES` with SQL functions, `Date` / `DateTime` from JS, `Decimal` precision, `INSERT … SELECT`	`reference/insert-values.md`
Async inserts (server-side batching)	`async_insert=1` , fire-and-forget vs wait-for-ack	`reference/async-insert.md`
Select and parse results	`JSONEachRow` reads, `JSON` with metadata, picking a select format	`reference/select-formats.md`
Parameterize queries	Binding values, special characters / escaping, "SQL injection?", `{name: Type}` syntax	`reference/query-parameters.md`
Sessions & temporary tables	`session_id` , `CREATE TEMPORARY TABLE` , per-session `SET` commands	`reference/sessions.md`
Modern data types	`Dynamic` , `Variant` , `JSON` (object), `Time` , `Time64`	`reference/data-types.md`
Custom JSON parse/stringify	Plug in `JSONBig` / `safe-stable-stringify` / a `BigInt` -aware serializer	`reference/custom-json.md`

Conventions used in answers

Always show

import { createClient } from '@clickhouse/client'

(Node, never Web).

Always
```
await client.close()
```
at the end of self-contained snippets; in long-running services, close on graceful shutdown.
For inserts, prefer
```
format: 'JSONEachRow'
```
and
```
values: [...]
```
unless the user's scenario requires otherwise.
For selects, prefer
```
await (await client.query({...})).json<RowType>()
```
for small / medium result sets; for bigger results suggest streaming.
When showing parameter binding, use ClickHouse's native
```
{name: Type}
```
syntax — never
```
$1
```
,
```
?
```
, or
```
:name
```
.
For DDL inside a cluster or behind a load balancer, set
```
clickhouse_settings: { wait_end_of_query: 1 }
```
on the
```
command()
```
call so the server only acknowledges after the change is applied. See https://clickhouse.com/docs/en/interfaces/http/#response-buffering.

Out of scope

This skill covers day-to-day coding against

@clickhouse/client

(Node). The following topics are intentionally not covered here:

Errors, hangs, type mismatches, proxy pathname surprises, log silence, socket hang-ups,
ECONNRESET
→ use the
```
clickhouse-js-node-troubleshooting
```
skill.
Streaming, Parquet, file streams, server-side bulk moves, progress streaming, async-insert throughput tuning — see
```
examples/node/performance/
```
.
TLS, RBAC / read-only users, deeper SQL-injection guidance — see
```
examples/node/security/
```
.
CREATE TABLE
patterns, deployment-shaped connection strings, replication / sharding choices — see
```
examples/node/schema-and-deployments/
```
.
Browser, Web Worker, Next.js Edge, Cloudflare Workers — use
```
@clickhouse/client-web
```
and see
```
examples/web/
```
.

Still Stuck?

```
examples/node/coding/
```
— the runnable corpus this skill is built on.
ClickHouse JS client docs
ClickHouse supported formats
ClickHouse data types

clickhouse-js-node-coding

NPX Install

Tags

SKILL.md Content