Load‑Testing the OpenClaw Rating API WebSocket over Secure TLS

1. Introduction

The OpenClaw Rating API powers real‑time rating and feedback features for gaming, e‑commerce, and social platforms. Because it relies on a persistent WebSocket connection secured with TLS, developers must validate that the service can handle peak traffic without compromising latency or security.

This guide walks you through a complete load‑testing workflow on the OpenClaw hosting environment, covering environment setup, tooling, TLS configuration, test execution, and best‑practice recommendations.

2. Test Environment Setup

Infrastructure

• Deploy a dedicated UBOS platform instance with at least 4 vCPU and 8 GB RAM to simulate a production node.
• Use a separate load‑generator VM (or container) with a high‑throughput network interface (10 Gbps NIC recommended).
• Enable Workflow automation studio to spin up and tear down test environments on demand.

Network considerations

• Place the load‑generator in the same VPC/subnet to minimize external latency.
• Configure MTU to 1500 bytes and enable TCP fast open if supported.
• Apply QoS policies to prioritize TLS‑encrypted WebSocket traffic.

3. Recommended Tooling

k6 – Scriptable load testing

k6 is an open‑source load‑testing tool that supports WebSocket protocols and TLS out of the box. Its JavaScript‑based scripting model lets you model realistic user behavior, including authentication handshakes and message bursts.

wrk – High‑performance HTTP benchmarking

wrk is a multi‑threaded HTTP benchmarking tool. While it does not natively support WebSockets, you can use wrk2 with custom Lua scripts or combine it with websocket‑client utilities to generate raw TCP traffic over TLS.

Both tools are lightweight, scriptable, and integrate well with CI pipelines, making them ideal for continuous performance validation.

4. Configuring TLS for the WebSocket

Certificates

UBOS simplifies TLS management with built‑in Let’s Encrypt integration. For load testing, generate a wildcard certificate for *.openclaw.example.com and install it on the API gateway:

ubos-admin createcert --domain *.openclaw.example.com --letsencrypt

Client settings

When scripting k6, enable TLS verification and specify the CA bundle:

import ws from 'k6/ws';
import { check } from 'k6';

export const options = {
  vus: 200,
  duration: '2m',
  tlsAuth: [{
    domains: ['openclaw.example.com'],
    cert: open('certs/client.crt'),
    key: open('certs/client.key')
  }]
};

export default function () {
  const url = 'wss://openclaw.example.com/rating';
  const response = ws.connect(url, { tags: { name: 'OpenClawRating' } }, function (socket) {
    socket.on('open', () => {
      socket.send(JSON.stringify({ action: 'rate', itemId: 123, score: 5 }));
    });
    socket.on('message', (msg) => {
      check(msg, { 'received ok': (m) => m.includes('ack') });
    });
    socket.setTimeout(() => socket.close(), 5000);
  });
  check(response, { 'connected': (r) => r && r.status === 101 });
}

For wrk, use the --tls flag and point to the CA file:

wrk -t12 -c400 -d30s --tls --tls-ca-cert=ca.pem https://openclaw.example.com/health

5. Running Load Tests

Sample k6 script

The script below simulates 200 concurrent users each establishing a WebSocket, sending a rating payload, and waiting for an acknowledgment. Adjust vus and duration to match your target load.

// rating-test.js
import ws from 'k6/ws';
import { check, sleep } from 'k6';

export const options = {
  stages: [
    { duration: '1m', target: 100 }, // ramp‑up
    { duration: '3m', target: 1000 }, // peak
    { duration: '1m', target: 0 }, // ramp‑down
  ],
  tlsAuth: [{
    domains: ['openclaw.example.com'],
    cert: open('certs/client.crt'),
    key: open('certs/client.key')
  }]
};

export default function () {
  const url = 'wss://openclaw.example.com/rating';
  const params = { tags: { name: 'OpenClawRating' } };
  const res = ws.connect(url, params, function (socket) {
    socket.on('open', () => {
      socket.send(JSON.stringify({ action: 'rate', itemId: Math.floor(Math.random()*1000), score: Math.ceil(Math.random()*5) }));
    });
    socket.on('message', (msg) => {
      check(msg, { 'ack received': (m) => m.includes('ack') });
    });
    socket.on('close', () => console.log('disconnected'));
    socket.setTimeout(() => socket.close(), 3000);
  });
  check(res, { 'status is 101': (r) => r && r.status === 101 });
  sleep(1);
}

Sample wrk command

Use wrk to stress the TLS handshake and HTTP upgrade path before the WebSocket is established:

wrk -t8 -c500 -d5m --latency --tls --tls-ca-cert=ca.pem https://openclaw.example.com/upgrade

Combine the two tools: wrk for raw TLS throughput, k6 for full WebSocket interaction.

6. Interpreting Latency and Error Metrics

Latency distribution

k6 provides a detailed latency histogram. Focus on the 50th, 95th, and 99th percentiles:

• P50 – typical user experience; aim for < 100 ms.
• P95 – outlier threshold; should stay < 250 ms.
• P99 – worst‑case; keep under < 500 ms to avoid churn.

Error types and handling

Common errors during TLS‑protected WebSocket tests include:

When errors spike at the 95th percentile, investigate TLS renegotiation settings and CPU‑bound cryptographic operations.

“TLS handshake latency can dominate total response time for short‑lived WebSocket connections; optimizing cipher suites and enabling session resumption are critical.” – Certificate Authorities Must Validate DNSSEC Signatures – UBOS

7. Best‑Practice Recommendations

Scaling

• Leverage Enterprise AI platform by UBOS to auto‑scale WebSocket workers based on CPU and TLS handshake latency.
• Use connection pooling and keep‑alive to reduce repeated TLS handshakes.
• Enable HTTP/2 or HTTP/3 where supported; they share TLS sessions across streams.

Monitoring

• Instrument the rating service with OpenTelemetry and push metrics to a Grafana dashboard.
• Track tls_handshake_duration, websocket_message_latency, and error_rate per minute.
• Set alerts for P95 latency > 250 ms or error rate > 1 %.

Security hardening

Follow the guidance from the UBOS security best‑practice article to ensure TLS is not only fast but also robust:

• Prefer TLS 1.3 with AEAD ciphers (e.g., TLS_AES_256_GCM_SHA384).
• Enable certificate transparency and OCSP stapling.
• Rotate certificates every 60‑90 days using UBOS’s automated Let’s Encrypt renewal.

For rapid prototyping, you can also explore UBOS templates for quick start, which include pre‑configured TLS settings for WebSocket services.

8. References

• Certificate Authorities Must Validate DNSSEC Signatures – UBOS (TLS performance insights)
• Security best‑practice article – UBOS
• k6 Documentation
• wrk GitHub Repository

9. Conclusion

Load‑testing the OpenClaw Rating API WebSocket over Secure TLS is essential for delivering a seamless, real‑time user experience. By provisioning a realistic test environment, leveraging k6 and wrk, configuring TLS correctly, and interpreting latency and error metrics, developers can confidently scale their services on the UBOS platform. Apply the best‑practice recommendations above, monitor continuously, and stay aligned with UBOS’s security guidelines to keep both performance and protection at peak levels.