---
title: "Load Testing SMS Ingestion Endpoints"
---

Load Testing SMS Ingestion Endpoints: Concurrency, Deadlocks, and D1 Safety: SMSRiver

-

[Skip to main content](#main-content)

[

smsriver.com

](/)

[Public Inboxes](/#numbers-section)
[Country Codes](/country-codes/)
[Workbench](/workbench/)
[Tools](/tools/)
[Developer API](/developer/)
[Pricing](/pricing/)

[Log In](/accounts/login/)

[
Log In
](/accounts/login/)
[
Get API Key

](/pricing/)

[

Home
](/)

-

[

Articles
](/articles/)

-

QA Automation & Testing

QA Automation & Testing

Published 2026-08-30

•

8 min read

#
Load Testing SMS Ingestion Endpoints: Concurrency, Deadlocks, and D1 Safety

Load test telephony endpoints under heavy concurrency using k6 and Locust. Prevent SQLite/D1 database locking and optimize thread pools for burst traffic.

Key Takeaway & Executive Summary

Simulate 10,000 concurrent inbound webhook deliveries using k6 to discover database write bottlenecks and race conditions before production launch.

When a major product launch or viral event triggers a 50x surge in signups, SMS authentication endpoints become severe bottlenecks. This guide details how to load test inbound verification and webhook endpoints safely without overwhelming telephony gateways.

##

Table of Contents

-
[
k6 Telephony Load Test Script
](#section-1)

-
[
Frequently Asked Questions
](#frequently-asked-questions)

##

1

k6 Telephony Load Test Script

javascriptimport http from 'k6/http';
import { check, sleep } from 'k6';

export const options = {
stages: [
{ duration: '30s', target: 50 },
{ duration: '1m', target: 200 },
{ duration: '30s', target: 0 },
],
};

export default function () {
const payload = JSON.stringify({
From: '+14155552671',
To: '+12025550199',
Body: 'Your verification code is 482910',
MessageSid: `SM${Date.now()}${__VU}`,
});
const res = http.post('https://api.smsriver.com/api/webhooks/inbound/sms/', payload, {
headers: { 'Content-Type': 'application/json' },
});
check(res, { 'status is 200': (r) => r.status === 200 });
sleep(0.1);
}

##

Frequently Asked Questions • QA Automation & Testing

How do serverless SQLite/D1 databases handle write load?

SQLite and Cloudflare D1 serialize writes single-threaded. For high-throughput webhook loads, buffer incoming payloads into Cloudflare Queues to prevent database lock contention.

##

Related Technical Articles & Deep Dives

[

QA Automation & Testing
8 min read

###
Testing Webhook Idempotency: Handling Duplicate and Out-of-Order SMS Events

](/articles/testing-webhook-idempotency-and-retries/)

[

Carrier Spam Filters & Deliverability
8 min read

###
Optimizing Network Routing for Zero-Drop Real-Time Telephony Events

](/articles/carrier-grade-network-routing-optimization/)

[

QA Automation & Testing
8 min read

###
Chaos Engineering for Telephony: Simulating Carrier Latency Spikes and DLR Timeouts

](/articles/simulating-carrier-delays-and-outages/)

Developer Sandbox

###
Automate Inbound SMS & OTP Testing

Eliminate flaky 2FA in CI/CD. Access dedicated virtual lines, programmable synthetic SMS webhooks, and Model Context Protocol (MCP) integrations.

[
Explore Developer Tiers →
](/pricing/)
[
View MCP Setup Guide
](/developer/mcp-setup/)

###

Developer Utilities

-
[
SMS Segment Calculator
Calculate segment counts and carrier costs in real time.
](/tools/sms-segment-calculator/)

-
[
Webhook Payload Validator
Verify JSON webhook payloads against provider schemas.
](/tools/webhook-payload-validator/)

-
[
SMS Delivery Troubleshooter
Diagnose carrier filtering and OTP delivery failure.
](/tools/sms-delivery-troubleshooter/)

-
[
E.164 Phone Number Formatter
Format phone numbers into international E.164 standard.
](/tools/phone-number-formatter/)

###

Public Verification Numbers

-
[
United States (+1)
View Line →
](/receive-sms/us/)

-
[
United Kingdom (+44)
View Line →
](/receive-sms/gb/)

-
[
Canada (+1)
View Line →
](/receive-sms/ca/)

-
[
Germany (+49)
View Line →
](/receive-sms/de/)

Copied to clipboard

FULL PACKET INSPECTION
SMS

###
Line: DE +49 ...

Timestamp: Just now

Extracted code

Copy Code

Message Body:

Copy Full Message

[
Open Live Inbox

](#)

smsriver.com

Central Office carrier inventory platform & developer SMS verification sandbox. Receive OTP codes instantly with zero SIM card requirement.

Public numbers·Live inboxes·Developer tools

Public Inboxes

- [United States (+1)](/receive-sms/us/)

- [United Kingdom (+44)](/receive-sms/gb/)

- [Canada (+1)](/receive-sms/ca/)

- [Philippines (+63)](/receive-sms/ph/)

- [Germany (+49)](/receive-sms/de/)

Developer & Tools

- [SMS Debugging Workbench](/workbench/)

- [Phone Number Inspector](/tools/phone-number-inspector/)

- [Bulk Phone Validator](/tools/bulk-phone-validator/)

- [Phone Lookup API](/developer/phone-lookup-api/)

- [E.164 Phone Formatter](/tools/phone-number-formatter/)

- [SMS Segment Calculator](/tools/sms-segment-calculator/)

- [Webhook Validator](/tools/webhook-payload-validator/)

Guides & Trust

- [Country Calling Codes](/country-codes/)

- [Troubleshooting Hub](/troubleshooting/)

- [Carrier Comparisons](/compare/)

- [Developer Reference](/developer/)

- [OpenAPI Specification](/openapi.json)

- [MCP Tools Manifest](/.well-known/mcp.json)

- [Privacy & Security Guides](/guides/)

- [Engineering Articles](/articles/)

© 2026 SMSRiver. Operating on Cloudflare Workers & D1. Adheres to CTIA Messaging Principles and 10DLC compliance standards.

[About](/about/)
[Contact](/contact/)
[Privacy Policy](/privacy/)
[Terms of Service](/guides/terms-of-service/)
Cookie Preferences