标签：#X

This will be the first Starship test flight for SpaceX as a public company, testing the market's appetite for the company's "fly, fail, fix" approach to rocket development, which often ends in fireballs.

DoorDash details the architecture behind Ask DoorDash, its AI-powered conversational shopping assistant, combining LLMs, specialized AI agents, MCP-based tooling, and an intelligence layer with persistent consumer memory and live backend data. Early results show up to 24% higher checkout conversion, 17% larger baskets, and improved intent accuracy using memory-backed sessions. By Leela Kumili

The problem with most web UIs is the gap between user action and visible feedback. A user clicks "like" and waits 200-400ms for the server to respond before the button changes. That delay reads as slowness even when the server is fast. The network round-trip is the ceiling. Optimistic UI inverts this: assume the operation will succeed, update the UI immediately, then reconcile with the server response when it arrives. If the server fails, roll back. React 19's useOptimistic hook gives you this pattern with minimal boilerplate and automatic rollback built in. The API const [ optimisticState , addOptimistic ] = useOptimistic ( state , // the current "real" state — synced from server updateFn , // (currentState, optimisticValue) => newOptimisticState ) optimisticState — during a pending transition, reflects the optimistic update. Once the transition completes, it reverts to state addOptimistic(value) — triggers an optimistic update, must be called inside startTransition Pattern 1: Like Button ' use client ' import { useOptimistic , useTransition } from ' react ' import { toggleLike } from ' @/actions/likes ' type LikeState = { liked : boolean ; count : number } export function LikeButton ({ postId , initialLiked , initialCount }: { postId : string initialLiked : boolean initialCount : number }) { const [ isPending , startTransition ] = useTransition () const [ optimisticState , addOptimistic ] = useOptimistic < LikeState > ( { liked : initialLiked , count : initialCount }, ( current ) => ({ liked : ! current . liked , count : current . liked ? current . count - 1 : current . count + 1 , }) ) function handleToggle () { startTransition ( async () => { addOptimistic ( ' toggle ' ) // updates UI immediately await toggleLike ({ postId }) // syncs with server }) } return ( < button onClick = { handleToggle } disabled = { isPending } > < Heart className = { cn ( ' h-4 w-4 ' , optimisticState . liked && ' fill-red-500 text-red-500 ' ) } /> < span > { optimisticState . count }

Washington D.C. has become a battleground for Uber and Waymo's competing views.

Described as the “feel-good movie of white-boy summer” by one extremist, the movie Citizen Vigilante has been hailed by the far-right as a way to convert moderates to their cause.

Try the demo: K-Saju Crew For fun only. K-Saju is an entertainment project. The K-Pop roles below are a playful interpretation of saju-inspired signals, not personality assessment or advice. A two-person compatibility page can stay stateless with almost no effort. Put both birth dates in a URL, render the result on the server, and the link is the record. No account, no database, no cleanup job. That was already a product rule in K-Saju. We do not retain personal inputs. A result is reproducible from its GET parameters. Then we built /crew : “What if your friend group debuted as a K-Pop group?” A creator makes a link, sends it to a group chat, and each friend enters their own birth date. At three to seven members, the app assigns distinct positions, shows pairwise chemistry, and creates a shareable poster. The fun part is the casting. The engineering problem is that the social flow needs a temporary shared state. A link cannot accumulate submissions by itself. This post is about the decisions behind that feature: where we allowed state, how we made the result durable without retaining a lobby forever, and how we kept the casting explainable instead of treating it as a black-box score. The conflict: a self-service group flow needs somewhere to collect data There were two clean but incomplete options. The first was to keep everything stateless. The creator would enter all members' dates at once, then receive a result URL. It matched our existing architecture, but it defeated the point of sharing a link. The person who starts the group often does not know everyone else's date, and asking them to collect it in a chat creates friction before the feature has started. The second was a conventional persistent group object. It would make joining easy, but it would turn a deliberately stateless service into one that keeps user-provided dates indefinitely unless we built retention and deletion policies around it. We chose a hybrid instead: The lobby is temporary state. It store

Throughout my career I have had to work with quite a few platform teams, and I was part of two for a couple of years. Some were bad, some were good and some should not have existed at all. I want to tell you my user experience, what I have seen work and what not and what you should definitely avoid doing. Be The Multiplier This is the main goal of a platform team. As a team, it needs to be a multiplier. If the platform team supports 10 teams, then each work it commits should multiply by 10. If the team member builds a new feature, it should be helpful for all the other teams. Otherwise, the platform team is an addition, and in most cases it is then better to split the platform team and add them to all other teams, instead of being a separate team. Because the amount of communication needed is in most cases quadratic in relation to the number of teams. Reducing Cognitive Load The platform should take away cognitive load for all the teams it supports. By doing so, they will have more time to implement business requirements. Let's say a platform team provides Gitlab runners or Azure Agents where people can run their CI/CD code on. They should not need to know how the runners are scaled, or how the agents are updated. This takes away the need for that skill set in all the teams. Build a Community A platform team has a unique position. It is building something that all other developers probably can build as well. Some could do it even better than the platform team itself. For some platform teams, their ego sometimes comes in to play or just straight up refuses their help because they are not the team. But it is not the job of the platform team to build a product, but a platform where everyone can thrive and/or build on. So onboard the community on the platform! The Law of Diffusion applies to almost all companies. You will have the innovators that want to build it themselves and the early adopters that will voice their opinion, but will not build it themselves. Those two

Microsoft also has to pay roughly $400 in damages to the user.

Earlier this month I shipped two premium templates — a SaaS landing page and a developer portfolio. Not a startup, not a SaaS, just templates. This post is about the two constraints I built them under, why they made the code better, and a few things I learned launching as a solo dev with zero audience. Constraint 1: zero dependencies beyond next, react, and tailwind Open the package.json of most templates and you'll find 20+ packages: icon libraries, animation libraries, carousel plugins, UI kits, utility libraries. Every one of them is a version conflict waiting to happen for the buyer, and most are replaceable with a few lines of code in 2026. What I used instead: Icons → inline SVG components. An icon component is ~10 lines. You need maybe 15 icons for a landing page. Animations → plain CSS. Scroll-blur navbars, gradient glows, an animated "typing" terminal — all doable with keyframes and transitions. No framer-motion. The dashboard mockup in the hero → pure CSS. Divs, borders, gradients. It looks like a product screenshot but it's ~80 lines of JSX and weighs nothing. Result: both templates land at ~100KB first-load JS, npm install takes seconds, and there is nothing to break when Next.js 16 arrives. Constraint 2: every piece of content in ONE typed config file The thing I hated most about templates I've used: content is smeared across 30 components. Changing a headline means hunting through JSX. So both templates keep all content in a single file — lib/content.ts for the landing page, site.config.ts for the portfolio. Headlines, nav, pricing tiers, testimonials, project lists, even the lines that animate in the fake terminal. Components are pure renderers of that config's TypeScript type. Two things surprised me here: TypeScript becomes your content linter. Forget an alt text, malform a link, give a pricing tier three features when the type expects a non-empty array — the build fails. Content mistakes surface at compile time. It forces better component design. W

Everyone can type "use client" . Almost nobody can say what survives the trip across it — and then something breaks: next build dies at prerender, the error names no file and no import chain, and the prop that killed it was an arrow one level down inside an object called options . Here's the uncomfortable secret: the boundary is one serializer . React walks every prop you hand a client component, encodes each value it has a branch for, and throws on the first one it doesn't. This post reads those branches out of React 19's Flight source — one file, no framework — and shows the two traps that pass code review and fail the build anyway. What crosses A prop is legal if the serializer has a branch for it. Everything else falls into one prototype check and throws. The whole contract fits on a screen: // app/page.tsx — a Server Component. Every comment is the serializer's verdict. export default function Page () { return ( < Chart title = "Q3" data = { { rows : [ 1 , 2 , 3 ] } } when = { new Date () } seen = { new Set ([ 1 ]) } index = { new Map () } rows = { fetchRows () } // an un-awaited Promise; the client calls use(rows) bytes = { new Uint8Array ( 8 ) } // ArrayBuffer, DataView, every typed array upload = { new File ([], ' a.csv ' ) } // there is no File branch — a File is a Blob form = { new FormData () } stream = { new ReadableStream () } kind = { Symbol . for ( ' chart ' ) } // global symbols cross; Symbol('chart') throws Slot = { Legend } // a client component: a function, and a client reference save = { saveRow } // a "use server" function: a server reference err = { new Error ( ' boom ' ) } // crosses — and arrives empty in production // no branch — every one of these throws at render match = { /q3/ } href = { new URL ( ' https://x.dev ' ) } cache = { new WeakMap () } user = { new User ( ' ada ' ) } bare = { Object . create ( null ) } onPick = { ( id ) => select ( id ) } /> ); } Four of those lines are the ones people get wrong: new Error() crosses, and product

Headline: React Compiler — formerly React Forget — shipped stable with React 19 and automatically memoizes components, hooks, and callbacks by analyzing data flow at build time. No dependency arrays to write; the compiler infers them. Here is what it handles, when it opts out, and whether you should delete your useMemo calls. Key takeaways React Compiler inserts useMemo , useCallback , and React.memo automatically at build time — no dependency arrays to maintain. Enable it in Next.js 15/16 with experimental.reactCompiler: true in next.config.ts . The compiler is conservative: if it cannot prove memoization is safe, it emits the component unchanged. "use no memo" is the escape hatch for functions the compiler should not touch. Run npx react-compiler-healthcheck@latest before enabling to see coverage and violations. What does React Compiler actually do? React Compiler transforms component and hook code at build time to insert memoization automatically. Instead of useMemo(() => expensiveCalc(a, b), [a, b]) , the compiler analyzes data flow, determines which values are stable across renders, and emits equivalent memoized code. The compiled output uses React's memo infrastructure at runtime. The compiler is babel-plugin-react-compiler — it works with any Babel-based build pipeline. How do I enable it in Next.js? // next.config.ts const nextConfig = { experimental : { reactCompiler : true , }, }; export default nextConfig ; Before enabling, run the healthcheck: npx react-compiler-healthcheck@latest The healthcheck reports optimizable component count, files with violations, and blocking patterns. Fix violations first for more coverage on day one. What does the compiler memoize? Components — equivalent to React.memo ; re-renders only when props change. Values — equivalent to useMemo ; computed results, derived arrays, objects. Callbacks — equivalent to useCallback : event handlers, functions passed as props. Dependencies are inferred from escape analysis — n

Headline: Partial Prerendering (PPR) in Next.js serves a static HTML shell from the CDN edge instantly, then streams Suspense-wrapped dynamic children from the origin in the same HTTP response. No full-page ISR staleness, no full-page origin latency. I shipped it on two production routes — here is the model. Key takeaways PPR serves a static HTML shell from the CDN edge , then streams dynamic Suspense children from the origin in the same response. The static shell is built at build time — outside <Suspense> renders statically; inside renders dynamically per request. PPR replaces the ISR vs. dynamic tradeoff for pages that are mostly static with isolated personalized sections. No changes to Server Components or Suspense — just experimental.ppr: 'incremental' in config and export const experimental_ppr = true per route. PPR and use cache are complementary : CDN delivery for the shell, origin memoization for dynamic islands. What does PPR actually do? PPR splits a page into two rendering phases within the same HTTP response. At build time, Next.js freezes everything that does not read dynamic request data into a static HTML shell on the CDN edge. At request time, the CDN delivers the shell at edge latency while the origin streams each <Suspense> boundary's content into the same response. On a product page: navigation, title, and description arrive at CDN speed. The in-stock badge and personalized recommendations stream from the origin a fraction of a second later. The user sees a nearly-complete page immediately. How is PPR different from ISR and streaming Suspense? Strategy First byte Dynamic freshness Staleness ISR (revalidate: N) CDN edge Whole page up to N seconds stale Full page Dynamic rendering Origin 100% fresh; waits for slowest query None Streaming Suspense (no PPR) Origin Fresh; TTFB includes origin latency None PPR CDN edge Dynamic islands 100% fresh Static shell only How do I enable PPR? // next.config.ts export default { experimental : { ppr : ' inc

Developers flagged a freshly filed, reproducible issue that should make anyone running background agents pause: Claude Code's background Opus subagents intermittently stall on their first turn and, instead of producing useful work, emit system-prompt fragments — including text shaped like authorization data — as their only output. It's labeled a security issue, it has a reproduction, and it's open. That's enough to treat it as a real, if intermittent, class of failure. Here's the mental model that matters: a subagent is not a trusted subprocess. It's an autonomous loop with access to a context window, a toolset, and — too often — the same credentials as its parent. When that loop stalls and dumps its prompt instead of its result, anything that was in context is now in output. Authorization-shaped text leaking is the canary: if the prompt carried a token, a session string, or an internal endpoint, that's what surfaces. The fix is structural, not reactive. Three rules: 1. Scope credentials per subagent, not per session. A background agent that only needs to read a repo shouldn't hold deploy keys. Hand it the narrowest token that completes its task and revoke it when the task ends. If the tooling can't scope credentials, that's a gap to close before you scale subagents. 2. Treat subagent output as untrusted. Anything a subagent returns — including error text, logs, and especially "stalled" dumps — should be parsed and sanitized before it touches shared state. Don't pipe raw subagent output into a context that feeds other agents or into any log that leaves your machine. 3. Separate the system prompt from the working context. The leak happened because authorization-shaped content sat in the same window the subagent could echo. Keep credentials and internal routing data out of the prompt that a stalled loop might surface. Put them in a side channel the model can call, not text it can print. The deeper lesson is about failure modes, not one bug. Most agent setups assume th

The feed showed a new entrant worth watching: Tencent has launched Hy3, a coding-focused AI model, with input tokens priced at $0.14 per million. For developers who live in the terminal running coding agents, that price point lands well below the per-token rates most frontier models charge, and it puts a major lab's coding model into the "cheap enough to leave running" category. What makes this interesting isn't just the number — it's the positioning. Hy3 is being pitched specifically as a coding AI, not a general chatbot, which suggests vendors are starting to carve out developer-facing models with their own pricing tiers rather than forcing coders to pay general-purpose rates. Developers spotted the launch in the daily AI news roundup and immediately started comparing it against the cost of running their existing agents. The catch, as always, is what the headline price doesn't tell you: output token cost, context-window limits, and how the model actually performs on real repository tasks all remain open questions. A low input price is meaningless if output is expensive or if the model needs five retries to get a diff right. Still, a credible cheap coding model from a major player is exactly the kind of pressure that nudges the whole category toward per-token transparency. If nothing else, it gives every other vendor a new number to justify theirs against.

Welcome to Learning Xahau, a series of articles dedicated to helping developers, builders, and blockchain enthusiasts better understand the Xahau ecosystem. Whether you're just getting started or already building advanced applications, these posts will explore Xahau's features, architecture, and best practices through practical examples and real-world use cases. If you've been building with Hooks on Xahau, you know the basic loop: write a C program, compile it to WebAssembly, install it on an account, and it fires automatically when that account is involved in a transaction. Simple and powerful, but until the 2026.6.21 major release, there were some friction points that made real-world hook architectures more complicated than they needed to be. This release ships three improvements that directly address those friction points: HookOnV2 : split the single HookOn bitmask into separate HookOnIncoming and HookOnOutgoing controls NamedHooks : assign a human-readable name to each hook slot, so senders can choose which hook to activate Simulate RPC : preview a transaction including all hook executions without spending fees or changing ledger state None of these require rewriting your hook logic. They are configuration and tooling improvements at the SetHook and transaction level. But they fundamentally change what you can build cleanly. All code in this article targets the Xahau Testnet ( wss://xahau-test.net ) and requires xahau.js 4.1.1 or later. Clone the companion repository: git clone https://github.com/Ekiserrepe/learningxahau20260621.git cd learningxahau20260621 npm install Copy .env.example to .env and fill in the seeds used across these examples: cp .env.example .env HUB_SEED = # account that installs the directional hook (07, 08, 09) NAMED_HUB_SEED= # account that installs and owns the named hooks (10, 11, 13, 14) SENDER_SEED = # account that sends payments targeting a named hook (12, 14) All accounts need testnet funds from the Xahau Testnet Faucet . HookOnV2: Di

ChatGPT is hiring a dedicated product manager to build experiences for families, caregivers, and older adults, according to a job posting.

It's unclear how the planet avoided its star's bloated red giant stage.

Notes from bringing up a PCIe WiFi module on i.MX8MQ; symptoms and how to diagnose them. Phy link never came up — what does this mean? This message is typically seen in dmesg as shown below. [ 3.828121] imx6q-pcie 33800000.pcie: iATU: unroll T, 4 ob, 4 ib, align 64K, limit 4G [ 4.807241] imx6q-pcie 33c00000.pcie: Phy link never came up [ 4.841482] imx6q-pcie 33800000.pcie: Phy link never came up [ 5.821279] imx6q-pcie 33c00000.pcie: Phy link never came up [ 5.830481] imx6q-pcie 33c00000.pcie: PCI host bridge to bus 0001:00 [ 5.854997] imx6q-pcie 33800000.pcie: Phy link never came up [ 5.862205] imx6q-pcie 33800000.pcie: PCI host bridge to bus 0000:00 It means one of the following The PCIe peripheral is not powered up. PCIe reset is not deasserted, so the chip is in reset. This could be because the DTB is deasserting an incorrect GPIO. Reference clock is not enabled Using the incorrect PCIe controller in the device tree. As we can see that both the PCIe controllers can report this. So first determine which controller is the peripheral hooked to. More on this in the next section. Which PCIe controller is my device on? ( &pcie0 vs &pcie1 ) The rule here is to match by address and not by label/name. If the schematic calls out controllers as PCIE1 and PCIE2, and the device tree lists pcie0 and pcie1, understand the mapping. The DTS label is arbitrary - match by register base ( @address in the node name), which is the same in the DTS reg and the reference memory map. For definitive addresses look in the .dtsi , as sometimes the manuals are misleading. Given below is a mapping table for i.MX8MQ DTS. | ADDRESS (in .dtsi) | Silicon (RM) Label &pcie0 | 0x33800000 | PCIe1 &pcie1 | 0x33c00000 | PCIe2 The addresses are listed in the chip’s memory layout are from processor reference manual. Below is snapshot from the i.MX8MQ reference manual, where the layout for the core A-53 is listed. Start Address | End Address | Size | Description 3381_0000 | 3381_3FFF | 4MB | PCIe-2 << inco

Most of us treat design systems as a functional problem: consistent colors, consistent spacing, consistent components. That part's solved for most teams now. The part nobody writes down is tone. How should this loading state feel? Should this error feel scary or manageable? Is this confirmation message robotic or human? Here's what I've learned paying attention to that layer. Four moments that carry the emotional weight In any app, four states do most of the emotional work: Loading Error Empty Success Get these four right and the whole product feels better, even if nothing about the actual functionality changed. ** Loading: ambiguity feels worse than the wait itself** jsx // Vague, slightly anxious < Spinner /> // Specific, calmer < div className = "loading-state" > < Spinner /> < p > Fetching your latest data... </ p > </ div > A spinner with no context makes people wonder if something's frozen. A spinner with a short label tells them exactly what's happening. Same wait time, different feeling. Errors: same bug, different emotional outcome jsx // Robotic " Error: Request failed with status 500 " // Human " Something went wrong on our end. Your changes weren't lost, try again in a moment. " The second version does three things the first doesn't: it's plain language, it removes blame from the user, and it tells them what to do next. That's the difference between an error that frustrates and one that reassures. Success: robotic vs genuine jsx // Robotic " Action completed successfully. " // Human " Done! Your changes are saved. " This message shows up constantly across a typical app. If it reads like a system log every time, the product feels cold. A small rewrite makes it feel like a person is on the other end. Micro-interactions: timing is part of tone too `jsx// No feedback during the wait, feels broken <button onClick={handleSave}>Save</button> // Immediate feedback, feels responsive <button onClick={handleSave}> {isSaving ? "Saving..." : "Save"} </button>` A butt

I got tired of SSHing into the box every time I shipped something, just to watch the logs come up. So I wanted a page in the admin panel where the lines scroll past as they happen, no dashboard, no Grafana, just the raw tail. The surprising part was how little I had to build for it, most of the pieces were already sitting on the server waiting for me to connect them. Here's the whole idea. The app writes JSON to stdout, systemd grabs that stdout and drops every line into the journal, and journalctl can follow the journal and hand the lines back live. All three of those already exist on an Ubuntu box. So the "live log viewer" is really just me spawning journalctl on the server and piping its output to the browser over an EventSource , which is a lot less code than it sounds like. journald is boring and well understood. SSE is boring and well understood (it's been in browsers since about 2011). Nobody gets excited about either one on its own. But snap the two together and you get a real-time log tail with no agent, no log shipper, no vendor, and nothing new to keep alive. Two defaults meeting each other and pretending to be a feature. Systemd thing People have opinions about systemd. Some of them are that you should avoid every part of it that you can, run your own supervisor, ship logs somewhere with your own daemon, and treat journald as a thing to route around. That's a fine hobby if you have the time for it. I don't. The box boots, systemd starts my unit, and when the unit writes to stdout the line ends up in the journal without me configuring anything. Being a purist here costs real hours and buys me a philosophy. Being pragmatic costs nothing and buys me a log tail. So this is the pragmatic path. If you're on a distro where journald is the default (Ubuntu, Debian, Fedora, most of them now) the setup below is basically free. Getting logs into the journal Here is the part most people overcomplicate. You do not "set up journald". You do not open a socket to it or p