Read what ships.

01Shopify · architecture

We gave AI agents a mobile dev environment

Engineering teams outgrew their local machines while running parallel AI mobile development agents, constrained by heavy builds and lack of iOS tools on Linux. To solve this, they built Remote Dev using warm pools of remote Macs connected via SSH alongside separate Linux VMs for Android virtualization, paired with agent skills and live browser streaming. This setup shifted workflow bottlenecks, increasing AI-merged pull requests from 6 percent to 61 percent.

DEPTH ■■■■■9 min read3 days ago

ArchitectureMobile

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02Martin Fowler · architecture

When Software Meets Hardware

A software engineering team modernizing a large-scale retail IoT system of 800,000 battery-powered sensors faced challenges integrating software practices with embedded hardware. By building physical sensor farms, virtual emulators, and self-diagnosing firmware, the team learned to design for intermittent connectivity, power efficiency, and fleet-level observability. The project succeeded by treating the physical world, hardware constraints, and engineering environments as core parts of the system lifecycle.

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03Shopify · architecture

How Shopify turns open models into task experts

Shopify uses a continual learning flywheel to post-train open models, such as NVIDIA Nemotron, to serve as dedicated subagents for specific tasks like GraphQL generation. By optimizing inference and utilizing automated self-healing to generate training data from production failures, the team successfully created task experts that outperform frontier models while reducing serving costs by 90-98% and improving response times.

DEPTH ■■■■■5 min read4 days ago

Architecture

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04Shopify · architecture

Cross-store product clustering across millions of stores

Shopify needed to group identical product listings from millions of different merchants under a single global identifier. To solve this at scale without comparing every possible pair, the team implemented a multi-stage pipeline using vector retrieval, a tiered scoring system of ML models, and a bounded graph clustering approach. This architecture successfully standardizes product data across the entire platform while controlling computational costs.

DEPTH ■■■■■13 min read5 days ago

Architecture

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05Martin Fowler · performance

Are Harnesses Worth the Cost?

An experiment was conducted to evaluate whether behavioral harnesses improve coding agent reliability when building a complex backend-for-frontend service. While frontier models succeeded consistently with or without a harness, the harness significantly increased token usage, time, and cost without improving final output. However, for a cost-optimized model, the harness improved success rates from 30 percent to 100 percent.

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06Shopify · tooling

Building Overexposed: understanding application exposure

The team built an automated scanner called Overexposed to track internet-facing services and verify access controls across Kubernetes and Cloud Run. By querying live cloud inventories and probing endpoints like an outsider, the scanner classifies exposure while avoiding false assumptions from static config files. As a result, the engineering organization improved accuracy and significantly reduced inconclusive findings over time.

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07Heroku · architecture

Front-End Web Deep Dive: Runtime Config

Front-end web applications traditionally bake environment variables into build artifacts, requiring a full rebuild to change configurations across environments. To solve this, a new approach injects runtime environment variables directly into the HTML document's head element as data attributes via a Cloud Native Buildpack. This enables zero-rebuild configuration changes while remaining compatible with browser security standards like CSP.

DEPTH ■■■■■3 min read10 days ago

Frontend

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08Martin Fowler · practice

Fragments: October 21

This post discusses commentary on AI usage in writing, the cancellation of the Grace Hopper Celebration, and reviews a detailed article by Cindy Sridharan on debugging with AI agents. The reviewed article highlights that AI agents excel at processing raw data rather than reading code first, and outlines a three-step debugging process involving controls, signals, and hypothesis validation. The lesson is that engineers must guide AI agents by setting up verification loops and providing raw data rather than human-centric abstractions.

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09Shopify · architecture

ShopGym: Realistic, reproducible sandboxes for shopping agents

Training and evaluating shopping agents is difficult due to changing live store environments, bot detection, and limited hand-built test stores. The team developed ShopGym, a framework that converts live storefronts into self-contained, anonymized sandbox shops and generates benchmark tasks. Evaluation showed that synthetic shops preserve key structural properties and behavioral alignment with live stores, giving agents a reliable environment to practice and improve.

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10Martin Fowler · practice

Practitioner Voice: The Writing Category Nobody has Named Yet

The author explores a missing category of writing called Practitioner Voice, which is grounded in earned experience and visible personal judgment rather than academic rigor, corporate polish, or AI generation. They examine how AI can be used as an extended cognitive tool for practitioners without losing human accountability. Ultimately, the piece argues that maintaining personal judgment and consequence-bearing experience is essential for authentic professional writing.

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11Shopify · tooling

Helix: The internal tool powering our Shopify app's native migration

Shopify is migrating its mobile apps from React Native to native Swift and Kotlin using an internal LLM-powered tool called Helix. Helix breaks migrations down into small checkpoints and enforces strict quality gates covering behavior, UI equivalence, architectural compliance, and human review. This iterative loop allows the team to reliably generate and migrate hundreds of screens to native code.

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12Martin Fowler · practice

Fragments: October 4

This post discusses the evolving role of software development and code in the era of large language models. It explores how shifting from deterministic building to inferential nurturing changes processes, why high-level representations remain critical for managing context windows, and how conceptual modeling becomes more important than the mechanical act of writing instructions.

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13Shopify · migration

Migrating Shop app from React Native to native

Shop migrated its mobile app from React Native to native Swift and Kotlin by leveraging AI coding agents to accelerate the rewrite. The migration resulted in improved startup times, higher session stability, smaller Android app sizes, and smoother rendering performance.

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14Martin Fowler · practice

Principles for effective slides

Presenters often rely on text-heavy slide decks that distract audiences and undermine storytelling. To fix this, speakers can use minimalist slides as a complementary visual channel to control the rate of information and manage cognitive load. This approach leads to more engaging presentations where visuals reinforce the spoken narrative rather than replace it.

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15Shopify · migration

Native is now the future of mobile at Shopify

Shopify is migrating its mobile applications from React Native back to native Swift and Kotlin. The team determined that the emergence of advanced coding agents significantly reduces the cost of maintaining platform parity, making native development the superior choice again. To execute this migration efficiently, Shopify developed a system called Helix and a CLI-driven, agent-addressable architecture to enable fast, autonomous testing.

DEPTH ■■■■■10 min read6 weeks ago

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16Shopify · architecture

How River takes security work from a fix to merge

Shopify developed an AI agent named River to automate security vulnerability remediation from dependency upgrades to pull request merges. The agent validates live states, replays and repairs fixes on current repository heads, and escalates context-dependent decisions to human engineers. This workflow reduced the open issue backlog by about 70 percent and increased freshness-gated security merges significantly.

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17Martin Fowler · practice

Build your slide template

Presenters often struggle with the visual design of slides and default to cluttered or uniform corporate templates. To build a better presentation foundation, the author recommends sticking to a restricted color palette, limiting the number of fonts, and using minimal layouts without unnecessary floodmarks like page numbers or logos. This approach results in a cohesive visual identity that provides greater flexibility during slide construction.

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18Martin Fowler · practice

Bliki: Sensible Default

The engineering post introduces the concept of a sensible default as an alternative to best practices in software development. Sensible defaults serve as reliable starting points for tasks in the absence of hard constraints, while still allowing teams to adapt and override them when context requires. Organizations like Thoughtworks utilize playbooks of these defaults to guide initial work while encouraging regular reflection and adjustment.

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19Martin Fowler · practice

Fragments: September 29

This post discusses observations on coding agents, focusing on their persistence, the role of training material in hacking behavior, and the need for greater safety measures and liability. It examines experiments with unlimited tokens and explores regulatory and educational perspectives on agentic AI.

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