# Built by NPCs

> Built by NPCs selects the tech news worth your attention and analyses tech products that make money: revenue, stack, running costs and the cost to build one.

Built by NPCs is a small software studio delivering precise, high-quality engineering at fair rates. We also publish tech news and product analysis. To work with us: https://builtbynpcs.com/build.

Tech news and product analysis for people who want to build with technology, in two sections:

- News: the tech news worth your attention each day: launches, outages, licence fights and the people building in public, with the sources each story relies on.
- Products: tech products that make money, analysed: revenue, pricing, how they found customers, the stack, running costs and what building one would take. Estimates are dated and list their assumptions.

Our team picks every story and reviews it before it goes out; AI helps with research and drafting. Every story opens with a summary and ends with its sources, linked.

Any story is available as markdown at its URL plus `.md` (for example https://builtbynpcs.com/stories/<slug>.md), with front matter that carries the canonical URL, section and dates.

Cite as: Built by NPCs (https://builtbynpcs.com), with a link to the story URL.

The full text of recent stories is in one file at https://builtbynpcs.com/llms-full.txt. A read-only JSON API (search, stories, weeks, sections, tools; no key) is described at https://builtbynpcs.com/openapi.json and listed at https://builtbynpcs.com/.well-known/api-catalog.

## News

Section page: https://builtbynpcs.com/sections/news

- [Harness learning: a 4B model trained to rewrite agent code beat its 35B teacher on average](https://builtbynpcs.com/stories/harness-learning-4b-model-rewrites-agent-code-beats-35b-teacher): A 4B-parameter model trained to rewrite an agent's code beat its 35B teacher on average (0.62 vs 0.56) on 21 unseen puzzle families, per a 28 September 2026 arXiv preprint. A fixed hand-built harness still averaged 0.69, and the commercial tools found so far tune prompt text only. (Oct 13, 2026, 4 min, markdown: https://builtbynpcs.com/stories/harness-learning-4b-model-rewrites-agent-code-beats-35b-teacher.md)
- [Fingerprinting survives cookie blocking, and one vendor selling it passed $50M in ARR](https://builtbynpcs.com/stories/fingerprinting-survives-cookie-blocking-fingerprint-50m-arr): Browser fingerprinting identifies a device from hardware and software traits, so clearing cookies or using incognito does not reset it. Google allowed the technique in its ad products from 16 February 2025, and Fingerprint, the main commercial vendor, reports passing $50M in ARR. (Oct 13, 2026, 5 min, markdown: https://builtbynpcs.com/stories/fingerprinting-survives-cookie-blocking-fingerprint-50m-arr.md)

## Weekly coverage

Index: https://builtbynpcs.com/weekly

- [Week 42, 2026](https://builtbynpcs.com/weekly/2026-w42): Mon 12 Oct to Sun 18 Oct 2026, 2 stories

## Services

- [Build with Built by NPCs](https://builtbynpcs.com/build): we build software for clients, by the week and as part of their team, from $599 a week.

## Optional

- [Editorial standards](https://builtbynpcs.com/standards): how stories are picked, sourced, reviewed and corrected, where AI helps, and how paid work is kept apart from what we publish
- [Terms](https://builtbynpcs.com/terms): what you may quote and reuse; answers that use a story should cite and link it
- [Open stats](https://builtbynpcs.com/stats): readership counted without cookies, published with the visits we filtered out (JSON: https://builtbynpcs.com/stats.json)
- [RSS feed](https://builtbynpcs.com/rss.xml): the latest 50 stories
- [Sitemap](https://builtbynpcs.com/sitemap.xml): every public URL