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In my previous articles, I’ve consistently emphasized a core architectural principle: once the render layer no longer dictates the entire data flow, the boundaries between State, Derived State, and Effects become critical. When we fall into the habit of stuffing every UI-affecting variable into generic "state," the system quickly loses its semantic structure. In modern frontend applications, this architectural gap becomes most glaring when dealing with asynchronous work. Async data is never merely "a value that will appear in the future." It carries complex semantics regarding its source, temporal validity, cancellation, error recovery, and invalidation. If these semantics aren't modeled explicitly, they inevitably get pushed down into the UI framework’s lifecycle—indirectly patched together through component mounts, effect dependencies, and callback guards. This brings us to the core question of this article: What does a system lose when the correctness of async work is forced to depend on the UI lifecycle? We are all incredibly familiar with this pattern: const data = await fetchSomething () setState ( data ) Or, using a standard UI framework hook: useEffect (() => { let cancelled = false fetchSomething (). then ( result => { if ( ! cancelled ) { setData ( result ) } }) return () => { cancelled = true } }, []) There is nothing inherently wrong with this code for simple use cases. It’s intuitive and perfectly aligns with how Promises are designed to work: trigger the operation, wait for the resolution, and write the result back into state. However, this mental model has a subtle downside. It encourages us to think of async work as simply calling setState after a Promise resolves. That may hold up for simple screens, but as an application grows, the model starts to expose structural problems. Promise Only Describes Completion, Not Ownership A Promise solves a very specific problem: A piece of work will complete in the future, and it will either succeed or fail. It c

📦 Code: github.com/USER/hls-multi-audio - replace before publishing TL;DR We'll add a working language picker to an HLS player. The hard part isn't the dropdown, it's the manifest. We'll author alternate audio with EXT-X-MEDIA audio groups, package it correctly, debug the classic "zero audio tracks" bug, and wire a switcher on hls.js v1.7 . Adaptive video, captions, the whole pipeline already works. Now someone wants an English/Spanish audio toggle. In HLS, "which audio can the viewer pick" is decided at packaging time and written into the master playlist. The player just displays it. Let's build it in that order. 1. Understand the structure (audio groups) HLS decouples video variants from audio renditions: Each audio rendition is an #EXT-X-MEDIA:TYPE=AUDIO entry pointing at its own media playlist. Renditions are bundled into a named audio group via GROUP-ID . Each video variant ( #EXT-X-STREAM-INF ) references a group with AUDIO="..." . A correct master playlist: #EXTM3U #EXT-X-VERSION:6 #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud",NAME="English",LANGUAGE="en",DEFAULT=YES,AUTOSELECT=YES,CHANNELS="2",URI="audio/en.m3u8" #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud",NAME="Espanol",LANGUAGE="es",DEFAULT=NO,AUTOSELECT=YES,CHANNELS="2",URI="audio/es.m3u8" #EXT-X-STREAM-INF:BANDWIDTH=2128000,CODECS="avc1.640028,mp4a.40.2",AUDIO="aud" video/720p.m3u8 #EXT-X-STREAM-INF:BANDWIDTH=1128000,CODECS="avc1.640020,mp4a.40.2",AUDIO="aud" video/480p.m3u8 Every attribute earns its place: LANGUAGE - BCP-47 code, used for the label. DEFAULT - plays when the viewer has no preference. AUTOSELECT - may be auto-picked from the OS language. CHANNELS - needed so the player can reason about stereo vs surround. BANDWIDTH on each video variant must include the audio group's bitrate , or your ABR logic works from a wrong total. 2. Author the renditions with FFmpeg Extract/encode each language's audio, then package. First, encode video-only and audio-only renditions: # video only (no audio), two ladder rungs

"It works on my test input" is the most dangerous sentence in on-device AI development. I typed that sentence - or some version of it - a dozen times while building Redacto, our on-device PII redaction app running Gemma 4 E2B on a Samsung Galaxy S25 Ultra. The model would redact a patient name from a clinical note, I would nod, and I would move on. Then I would hand the phone to a teammate, they would type a police report, and the model would redact the suspect description instead of the victim name. The problem is not the model. The problem is that manual spot-checking is not validation. You are testing a single input against your own expectations, with all the confirmation bias that entails. When you have five domain modes (HIPAA, Financial, Tactical, Journalism, Field Service), three difficulty levels, and two candidate models, you need something systematic. You need a benchmark suite. This post covers how I built one - from dataset curation to scoring methodology to on-device infrastructure - for a hackathon app running entirely on a phone. No cloud. No API calls. No data leaving the device. Why Not Use an Existing Framework? The LLM evaluation space has mature tools. EleutherAI's lm-eval-harness is the community standard for evaluating language models against academic benchmarks like MMLU, HellaSwag, and ARC. Stanford's HELM (Holistic Evaluation of Language Models) provides a multi-metric evaluation framework with standardized scenarios. Google's BIG-bench offers hundreds of tasks for probing specific capabilities. These frameworks are excellent for what they do. They are also completely wrong for this problem, for three reasons. First, they assume server-side inference. lm-eval-harness expects to call a model through an API or load it in PyTorch on a GPU server. Redacto's model runs on a Qualcomm Hexagon NPU inside a phone. There is no Python runtime, no HuggingFace tokenizer at evaluation time, no way to hook into the framework's inference loop. Second, their

Plenty of SEO audits end with a single tool report. You run Lighthouse, screenshot Search Console coverage, save a "12 issues found" panel, and call it done. The trouble is that most audits finished that way silently revert within three months. Someone publishes a new post, refactors a component, swaps a font, and the issue quietly comes back. Nobody notices. Over the last five days I actually audited my four-language blog (ko/ja/en/zh, 298 posts per language). Five items, all fixed. But what I really want to talk about isn't what I fixed. It's that the five fixes mattered less than the build gates that keep them from ever returning. An audit should be a loop, not an event. Why a one-report audit always comes back Most technical SEO issues aren't "the code is wrong." They're "an invariant was never enforced anywhere." Take a clear rule: a published post must not link internally to a draft. Obvious enough. But if a human has to remember that every time, then the moment a recommendation generator pulls in one draft slug, a 404 is born. The report catches that 404 and shows it to you, but it does nothing to prevent the next one. So I ran the audit as a three-step loop. Measure. Fix the biggest item first. Then turn that item into a checker and nail it to the build . Skip the third step and the first two become a chore you repeat every six months. Once a gate is in place, the same class of problem makes npm run build fail. A pipeline enforces the rule, not human memory. This isn't a new invention. It's the same logic by which tests prevent bug regressions, applied to the content and markup layer. It's just oddly rare in SEO, where most teams leave "SEO checks" as a quarterly manual task. The five items I actually ran over five days Measurement first. Each item got a before/after in numbers, not a vibe that "things feel better" but reproducible figures. (The raw log of all five lives on the improvement history page too.) Date Item Before After Gate 07-02 relatedPosts int

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Cloudflare and AWS both implemented x402 stablecoin micropayments at their edge networks within two weeks. The open protocol under the Linux Foundation revives HTTP 402 for agent-to-service payments with sub-cent transaction costs. Coinbase reports 169 million transactions in year one. Enterprise tax and invoicing gaps remain unresolved. By Steef-Jan Wiggers

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After stumbling by on an old machine for too long I finally got a new Macbook. I am now on current...

Meme Monday! Today's cover image comes from the last thread. DEV is an inclusive space! Humor in...

The Problem Nobody Talks About Everyone's posting AI-generated videos — characters speaking with lip-sync, manga panels coming alive, virtual idols dancing. The pitch: "just describe what you want." I tried. For months. Here's what I got: Character's face morphed by frame 2 "Slowly looks up" became "violent head shake" Voice-over sounded like Google Translate Same prompt, 3 runs, 3 completely different results No idea what to include or how long the prompt should be Tutorials were either too vague ("be detailed") or too technical (parameter tuning from line 1). The real issue: video prompts are structurally different from text/image prompts. You need to simultaneously control visuals, motion, audio, camera, and consistency constraints — in the right order, at the right length. What I Found A Skill in the Model Studio official repo called happyhorse-prompt-studio . It doesn't teach you theory — it asks you questions and assembles the prompt for you . 4-phase flow: 1. Inspiration Menu Shows you 4 "flavors" of what HappyHorse can do: Flavor What it does A · Voiced Manga Drama Characters talk to each other, with voice + lip-sync B · Character Voice PV Single character self-introduction, 8-10 sec C · Manga Panel Motion Static manga panel starts breathing D · Virtual Idol MV Idol performance with choreography 2. Discovery Asks you conversationally: character appearance, scene, emotion, dialogue, voice type, art style, camera. 3. Prompt Assembly Assembles using the HappyHorse Formula : Scene + Subject + Motion + Audio + Quality Key techniques: @「Image n」 syntax locks character identity across shots Dialogue ≤15 characters (split shots if longer) Japanese prompts work best (HappyHorse is JP-optimized) Always end with キャラの顔・髪・衣装が変わらない (face/hair/outfit stays unchanged) 4. Quality Check Auto-reviews: completeness, compliance, cost estimate, optimization tips. Before vs. After Dimension Writing myself With Prompt Studio Attempts needed 10-20 before one usable 2-3 to satisfacti

In Part 1 , we introduced the idea that meaningful product design isn't about adding more — it's about knowing what to remove. Now let's examine this principle through a specific lens: meditation and mindfulness products. The Paradox of "More Mindfulness" Walk through any app store's health & wellness category and you'll find a strange contradiction: apps that promise to reduce your mental clutter by adding more things to your daily routine. Daily meditation streaks Guided breathing exercises (14 varieties) Sleep stories narrated by celebrities Mood tracking with 47 emotion labels Community challenges, leaderboards, badges AI-generated personalized recommendations The message is clear: "To feel less overwhelmed, here are 12 more things to do every day." This isn't just ironic — it's counterproductive. The cognitive load of managing a wellness routine can itself become a source of stress. The Feature Ceiling I've been studying meditation products for the past few months, and a pattern emerges across the market: Product Core Feature Total Features After 2 Years Calm Guided meditation ~40+ (stories, music, masterclasses) Headspace Guided meditation ~35+ (focus music, move, sleep casts) Balance Personalized meditation ~15 (singles, plans, skills) The most interesting case is Balance, which has fewer features but higher per-session engagement. Users spend more time meditating, not more time navigating. This isn't accidental. There's a cognitive principle at work: decision fatigue applies to self-care too. Every additional feature is another decision the user has to make before they can simply be still . What OneZen Gets Right OneZen takes the subtraction principle to its logical endpoint. Instead of asking "What can we add?" the product asks "What can we remove while still delivering value?" The result is a meditation tool that doesn't feel like a tool at all. It feels like breathing room. Three design choices worth studying: 1. No onboarding questionnaire. Most apps ask

This post was originally published on MatrixTrak.com — the production reliability toolkit for trading bot operators and .NET engineers. Complete WebSocket auto-reconnect guide for trading bots. Implement automatic reconnection with exponential backoff, heartbeat ping-pong, message gap detection, and state recovery. WebSocket connections drop. Not maybe. Definitely. Exchanges reset connections every 24 hours. Networks glitch. Load balancers rotate. HTTP proxies timeout. Your trading bot will experience disconnects. The question isn't whether you'll disconnect—it's whether your bot recovers correctly when you do. If you only do three things Implement automatic reconnection with exponential backoff and jitter. Track sequence numbers to detect missed messages. Always verify state via REST after reconnect. Never trust WebSocket alone. WebSocket Auto-Reconnect Quick Start If you just need a working auto-reconnect loop right now, here's the minimum viable implementation: class AutoReconnectWebSocket { private ws : WebSocket | null = null ; private reconnectAttempts = 0 ; private maxRetries = 10 ; private shouldReconnect = true ; async connect ( url : string ): Promise < void > { return new Promise (( resolve , reject ) => { this . ws = new WebSocket ( url ); this . ws . onopen = () => { this . reconnectAttempts = 0 ; resolve (); }; this . ws . onclose = ( event ) => { if ( this . shouldReconnect ) { const delay = this . backoff (); console . log ( `[AutoReconnect] Closed ${ event . code } . Reconnecting in ${ delay } ms` ); setTimeout (() => this . connect ( url ), delay ); } }; this . ws . onerror = () => { /* onclose fires next */ }; }); } private backoff (): number { const base = 1000 ; const max = 30000 ; const delay = Math . min ( base * Math . pow ( 2 , this . reconnectAttempts ++ ), max ); return delay + delay * 0.2 * ( Math . random () * 2 - 1 ); // +20% jitter } close (): void { this . shouldReconnect = false ; this . ws ?. close (); } } This handles the core auto

これは、Apidog が API テストおよび API ライフサイクル管理のためのコマンドラインツールである Apidog CLI をどのように開発したかを共有する全10回のシリーズです。順番に読むか、必要なテーマから直接参照してください。 今すぐApidogを試す タイトル 焦点 1 当社は126のMCPツールを構築しました。しかし、それはAgentにとって最良の解決策ではありません 問題の発見 2 なぜ当社は全く新しいApidog CLIを開発したのか アーキテクチャ開発 3 黄金律：CLIは事実を生成し、モデルは事実に従って行動する 核となる哲学 4 agentHints : CLIにAgentとの会話を教える 構造化出力 5 SKILL：運用経験をコードとして出荷する 運用経験 6 数字は嘘をつかない：ツール呼び出しは30%減、トークンは25%減 定量的結果 7 PRDからテストループまで：Apidog CLIによる完全なAgentワークフロー 実践的なチュートリアル 8 なぜCI/CD互換性がAgentツールにとって不可欠なのか DevOpsの視点 9 AIブランチ：AI Agentによるより安全なプロジェクト変更 セキュリティレイヤー 10 Spec-Firstは昨日。Skill-Firstへようこそ。 ビジョンと未来 当社は、MCPが最適化しない複雑なワークフロー、つまり検証ゲートと構造化された実行を伴うワークフローを処理するために、CLI + SKILLを構築しました。 MCPはその目的を果たし続けています CLI + SKILLに入る前に、前提を明確にします。 Apidog MCPは現在も利用可能で、メンテナンスされています。 MCPは、プロトコルに従って標準化されたツール接続を提供します。特に以下の用途に適しています。 シンプルで明確に定義された操作 MCPベースのワークフローを好むユーザー MCP準拠クライアントとのエコシステム統合 当社はMCPを置き換えたわけではありません。CLI + SKILLはMCPを補完するために構築されました。 MCPは ツール接続 に優れています。一方で、検証、読み戻し、実行確認を伴う多段階のR&Dワークフローでは、Agentに対して 実行可能なエンジニアリングプロセス を提供するほうが安定します。そこにCLI + SKILLが適合します。 タスクごとに使い分けると、次のようになります。 タスクタイプ 推奨されるアプローチ シンプルなツール呼び出し（例：エンドポイントの取得） MCPまたはCLI。どちらも機能します 多段階ワークフロー（例：テストの作成、検証、実行） CLI + SKILL。より良い体験になります CI/CD統合 CLI。ネイティブに適合します MCPエコシステム統合 MCP。プロトコル標準に適合します 古いCLI：最後にテストを実行する Apidog CLIは長年、APIテストを実行するためのコマンドラインのエントリポイントでした。 apidog run --project <projectId> --test-scenario <scenarioId> --environment <environmentId> この基盤は今も重要です。チームには以下を行うための信頼できる方法が必要です。 ターミナルからAPIテストを実行する CIパイプラインでレポートを生成する 自動化ワークフロー内で品質ゲートを維持する ただし、古いCLIの主な役割は テスト実行 でした。つまり、ワークフローの終盤で使われます。 設計 → ドキュメント化 → モック → デバッグ → テスト → [CLIがテストを実行] CLIは最後のステップでした。他の作業が完了したあとに、既存のテストを実行するためのものだったのです。 新しい要件：Agentにはより多くの操作が必要 API開発は変化しています。 AI Agentは現在、APIライフサイクルの複数段階に参加します。 段階 Agentの活動 API設計 PRDからエンドポイント定義を生成する テスト生成 API仕様からテストケースを作成する デバッグ 障害を分析し、修正案を提示する 移行 プロジェクト間でAPIを移動する メンテナンス API変更時にテストを更新する このようなワークフローでは、CLIは既存テストを最後に実行するだけでは不十分です。 Agentが安定して作業するには、CLI側で次の操作を提供する必要があります。 APIアセット（エンドポイント、スキーマ、環境）を読み取る テストアセット（テストケース、テストシナリオ）を作成または更新する 書き込み前に構造化された変更を検証する 変更をプロジェクトに書き戻す 実行結果を検証