Ken Ahrens — co-founder and CEO of Speedscale. Open source, homelabs, and running AI locally.https://kahrens.com/https://kahrens.com/posts/running-my-own-local-ai-stack/https://kahrens.com/posts/running-my-own-local-ai-stack/I've been an open source fan for a long time. Lately that's meant building my own local AI stack so I'm not at the mercy of token bills and shifting licenses.Tue, 16 Jun 2026 09:00:00 GMThttps://kahrens.com/posts/we-wont-train-on-your-data-is-not-a-security-architecture/https://kahrens.com/posts/we-wont-train-on-your-data-is-not-a-security-architecture/MSA clauses and contractual guarantees aren't an architecture. If your production traffic leaves your cloud, you're trusting a policy, not a system.Wed, 10 Jun 2026 09:00:00 GMThttps://kahrens.com/posts/logs-told-me-something-broke-traffic-showed-me-what/https://kahrens.com/posts/logs-told-me-something-broke-traffic-showed-me-what/Capture production traffic and store it in your own Elasticsearch with Speedscale BYOC. Pull it locally with es-gather.py and reproduce bugs with proxymock.Tue, 02 Jun 2026 09:00:00 GMThttps://kahrens.com/posts/our-follow-up-rate-was-abysmal-so-i-built-my-own-tool/https://kahrens.com/posts/our-follow-up-rate-was-abysmal-so-i-built-my-own-tool/I had a number stuck in my head: eight to 10 touches before deciding a prospect isn't interested...Tue, 02 Jun 2026 09:00:00 GMThttps://kahrens.com/posts/ai-rework-tax/https://kahrens.com/posts/ai-rework-tax/I tested 100 bugs across 240 microservices the model has never seen. Alert only: 51% pass rate, wrong service 34% of the time. Traffic captures: 77%.Mon, 01 Jun 2026 09:00:00 GMThttps://kahrens.com/posts/notes-local-ai-simpler-than-you-think/https://kahrens.com/posts/notes-local-ai-simpler-than-you-think/I got caught flat-footed twice by the same customer. I have an office hours call with them almost...Tue, 19 May 2026 09:00:00 GMThttps://kahrens.com/posts/traffic-context-confirmed-fix-3-minutes/https://kahrens.com/posts/traffic-context-confirmed-fix-3-minutes/Traffic Context is the missing piece in most debugging workflows. We ran our autonomous agent on a real production bug — it found the root cause, wrote a reproduce harness, applied the fix, and confirmed it. Here's what that looked like.Mon, 18 May 2026 09:00:00 GMThttps://kahrens.com/posts/the-ultimate-guide-to-a-smooth-dev-environment/https://kahrens.com/posts/the-ultimate-guide-to-a-smooth-dev-environment/The Ultimate Guide to a Smooth Dev Environment Originally published on 2025-12-11 at...Thu, 09 Apr 2026 09:00:00 GMThttps://kahrens.com/posts/top-5-wiremock-alternatives-best-practices/https://kahrens.com/posts/top-5-wiremock-alternatives-best-practices/Top 5 WireMock Alternatives Best Practices Originally published on 2025-12-22 at...Tue, 07 Apr 2026 09:00:00 GMThttps://kahrens.com/posts/from-datadog-to-test-suite/https://kahrens.com/posts/from-datadog-to-test-suite/Learn a practical workflow to convert Datadog metrics, traces, and incidents into CI tests that catch regressions before deploy.Mon, 06 Apr 2026 09:00:00 GMThttps://kahrens.com/posts/why-you-should-stop-buying-saas-and-start-building-it/https://kahrens.com/posts/why-you-should-stop-buying-saas-and-start-building-it/LLMs have collapsed the cost of custom internal tools. Here's the startup distribution problem I've watched kill companies — and how I vibe-coded my way out.Fri, 03 Apr 2026 09:00:00 GMThttps://kahrens.com/posts/test-code-changes-with-claude-code-using-real-traffic/https://kahrens.com/posts/test-code-changes-with-claude-code-using-real-traffic/Claude Code can write features and fix bugs, proxymock traffic snapshots give me the integration tests, replays.Tue, 25 Nov 2025 09:00:00 GMThttps://kahrens.com/posts/better-integration-tests-in-cursor-using-proxymock/https://kahrens.com/posts/better-integration-tests-in-cursor-using-proxymock/Cursor can scaffold new API calls, proxymock traffic snapshots give me the integration tests, replays.Wed, 19 Nov 2025 09:00:00 GMThttps://kahrens.com/posts/how-to-build-a-traffic-capture-system/https://kahrens.com/posts/how-to-build-a-traffic-capture-system/Learn how to build a production-grade traffic capture system using proxies, eBPF, and tcpdump.Tue, 21 Oct 2025 09:00:00 GMThttps://kahrens.com/posts/how-to-tame-your-ai-agents-from-900-in-18-days-to-coding-smarter/https://kahrens.com/posts/how-to-tame-your-ai-agents-from-900-in-18-days-to-coding-smarter/It started with a curiosity and ended with a $900 bill. Eighteen days. Three AI coding agents: Claude...Tue, 12 Aug 2025 09:00:00 GMThttps://kahrens.com/posts/record-api-calls-in-prod-replay-in-dev-to-test/https://kahrens.com/posts/record-api-calls-in-prod-replay-in-dev-to-test/Introduction Have you ever experienced the problem where your code is broken in...Sun, 28 Jul 2024 09:00:00 GMThttps://kahrens.com/posts/testing-llms-for-performance-with-service-mocking/https://kahrens.com/posts/testing-llms-for-performance-with-service-mocking/While incredibly powerful, one of the challenges when building an LLM application (large language...Tue, 26 Mar 2024 09:00:00 GMT