---

name: clickhouse-deploy-integration description: | Deploy ClickHouse-backed applications to Vercel, Fly.io, and Cloud Run with connection pooling, secrets, and health checks. Use when deploying applications that connect to ClickHouse Cloud, configuring platform secrets, or setting up deployment pipelines to serverless or container hosts. Trigger with "deploy clickhouse app", "clickhouse Vercel", "clickhouse Cloud Run", "clickhouse production deploy", "clickhouse Fly.io". allowed-tools: Read, Write, Edit, Bash(vercel:), Bash(fly:), Bash(gcloud:*) version: 1.7.0 license: MIT author: Jeremy Longshore jeremy@intentsolutions.io tags:

• saas
• database
• analytics
• clickhouse
• olap compatibility: Designed for Claude Code

---

ClickHouse Deploy Integration

Overview

Deploy applications that connect to ClickHouse Cloud from serverless and container platforms with proper connection management and secrets handling. The same platform-agnostic connection module drives all three targets — Vercel, Fly.io, and Cloud Run — so only the secrets mechanism and runtime model change per platform.

Prerequisites

• ClickHouse Cloud instance (or self-hosted with public endpoint)
• Platform CLI installed (vercel, fly, or gcloud)
• Application tested locally against ClickHouse

Instructions

Step 1: ClickHouse Connection Module (Platform-Agnostic)

Write a singleton client so a serverless cold start reuses one connection instead of opening a new pool per invocation. Keep max_open_connections low for serverless and enable compression to cut egress.

// src/db.ts — singleton for serverless-safe connections
import { createClient, ClickHouseClient } from '@clickhouse/client';

let client: ClickHouseClient | null = null;

export function getClickHouse(): ClickHouseClient {
  if (!client) {
    client = createClient({
      url: process.env.CLICKHOUSE_HOST!,         // https://<host>:8443
      username: process.env.CLICKHOUSE_USER!,
      password: process.env.CLICKHOUSE_PASSWORD!,
      database: process.env.CLICKHOUSE_DATABASE ?? 'default',
      request_timeout: 30_000,
      max_open_connections: 5,    // Low for serverless (many cold starts)
      compression: {
        request: true,            // Saves egress bandwidth
        response: true,
      },
    });
  }
  return client;
}

Step 2: Pick a platform and deploy

Choose the target that matches your runtime model, then set secrets and deploy. All three import the getClickHouse() module above unchanged.

• Vercel (serverless functions) — vercel env add per secret; best for API endpoints. Keep max_open_connections at 1-3.
• Fly.io (containers) — fly secrets set + a fly.toml health check; best for long-running apps with persistent connections.
• Cloud Run (containers) — secrets via Secret Manager (--set-secrets); best for event-driven workloads. Set --min-instances=1 to avoid cold-start connection churn.

Full per-platform commands, the Next.js App Router query example, fly.toml, the Cloud Run deploy script, and a platform comparison table: Platform deployment walkthrough.

Step 3: Add health check and graceful shutdown

Expose a /health endpoint that pings ClickHouse (drives Fly.io / Cloud Run readiness probes) and close the client on SIGTERM/SIGINT so pending inserts flush before the container is recycled. Full code: Production patterns.

Output

Running this skill produces a deployable ClickHouse-connected application:

• src/db.ts — a singleton ClickHouse client, serverless-safe and compressed.
• Platform config with secrets set: Vercel env vars, fly.toml + fly secrets, or a Cloud Run service wired to Secret Manager.
• A /health endpoint reporting { status, clickhouse: { connected, latencyMs } }.
• Graceful-shutdown handlers that flush pending inserts on SIGTERM/SIGINT.
• A live deployment reachable over HTTPS on the chosen platform.

Error Handling

Issue	Cause	Solution
ECONNRESET on Vercel	Function timeout	Reduce query scope, increase timeout
TLS handshake failed	Wrong port	Use port 8443 for Cloud
Secret not found	Env var not set	Check platform secret config
Cold start latency	New connection per invocation	Use min-instances=1 on Cloud Run

Examples

Deploy an analytics API to Vercel: set the four CLICKHOUSE_* secrets with vercel env add, drop the getClickHouse() module in src/db.ts, and add a route that runs a parameterized SELECT ... GROUP BY event_type. See the full Next.js App Router handler under the Vercel section of the Platform deployment walkthrough.

Deploy a long-running container to Fly.io: add a [[http_service.checks]] block pointing at /health, fly secrets set the ClickHouse credentials, then fly deploy — see the complete fly.toml in the Platform deployment walkthrough.

Deploy an event-driven service to Cloud Run: store host + password in Secret Manager, wire them with --set-secrets, and set --min-instances=1. Full deploy script in the Platform deployment walkthrough.

Resources

• ClickHouse Cloud Connection
• Vercel Environment Variables
• Fly.io Secrets
• Cloud Run Secrets

Next Steps

For data ingestion patterns, see clickhouse-webhooks-events.