{"slug": "show-hn-cardgo-reusable-end-to-end-encrypted-context-cards-for-ai-chats", "title": "Show HN: CardGo – Reusable, end-to-end encrypted context cards for AI chats", "summary": "CardGo, a new Chrome extension from an independent developer, lets users create reusable, end-to-end encrypted context cards to attach to AI chats including ChatGPT, Claude, Gemini, Perplexity, and Grok. Cards are encrypted with AES-256-GCM, keys are generated on the user's device and never sent to CardGo, and the company stores only ciphertext. The extension is available now, with a desktop app and mobile keyboard planned.", "body_md": "### Work\n\nProduct design lead · Remote\n\nPrefers concise briefs\n\nTimezone: Tokyo (GMT+9)\n\nSave your context once. The CardGo Chrome extension brings it to any AI chat — ChatGPT, Claude, Gemini, Perplexity, Grok, and more.\n\nYour cards, at a glance\n\nEncrypted at rest · Nothing shared until you attachProduct design lead · Remote\n\nPrefers concise briefs\n\nTimezone: Tokyo (GMT+9)\n\nTraining for a half marathon\n\nVegetarian\n\nKnee-friendly plans only\n\nPlanning life with two little ones\n\nWeekend ideas\n\nBudget-conscious picks\n\nEncrypted at rest · Nothing shared until you attach\n\nWorks with\n\nHow to use CardGo\n\nInstall the Chrome extension, create a card, and attach it when you chat with AI.\n\nAdd CardGo to Chrome. Your cards will be ready beside the AI chats you use.\n\nSave the context you want to reuse, from your role and goals to your preferences.\n\nChoose the card you need in ChatGPT, Claude, Gemini, Perplexity, Grok, or another supported AI.\n\nComing soon\n\nA dedicated desktop app for your cards and context.\n\nA mobile keyboard for Android and iOS that brings your cards into any app.\n\nPick an everyday scenario and watch the same question answered twice—once without your card, once with it.\n\nYour card — a few lines about you\n\nYour question\n\nA recorded example. Nothing leaves your browser—pick a scenario and watch the same question answered twice.\n\nHow it works\n\nProfile, Now, Goals, Guidance, Memory, Timeline, Skills. Fill in what’s useful, skip the rest—empty sections save nothing. Pick one below to see what goes in it.\n\nWhat is this card about?\n\nWho or what this card is about. The things you would say first if someone asked, and would still be true next quarter.\n\nStable — changes in months, not days\n\nProfile\n\nNew in CardGo\n\nKeeping a profile current is work, and work is why profiles go stale. So CardGo drafts the cards, surfaces the right one as you type, and files what you say back where it belongs.\n\nLive now\n\nOne paragraph in — a named set out, already sorted into sections. You keep the ones that are right.\n\nI lead product design at a startup in Tokyo, I’m training for a half marathon, and I have two kids under five.\n\nSuggestions and Capture read only your own draft, and read it **on your device** — a small model in your browser, not a server. CardGo never reads the conversation, and nothing is attached, saved, or changed until you tap.\n\nWhy CardGo\n\nChoose what each chat knows\n\nAttach only the card a conversation needs. Nothing else is shared.\n\nSwitch AIs without starting over\n\nOne card works in ChatGPT, Claude, Gemini, Perplexity, and Grok.\n\nEncrypted end-to-end\n\nCards are locked on your device with a key we never receive. We store ciphertext.\n\nFilter sensitive details before sharing\n\nReview the snapshot before you attach a card. Sensitive values are filtered on your device, so you can see exactly what the AI will receive.\n\nShare one card—not your profile\n\nSend a read-only card when it helps. You decide exactly what goes with it.\n\nYour cards are sealed on your device with a key we never receive. What reaches CardGo is ciphertext — we can sync it, count it, and delete it, but we cannot read it.\n\nWhat you write\n\nWork\n\nProduct design lead · Timezone: Tokyo (GMT+9)\n\nWhat our servers store\n\nAn opaque block of ciphertext.Ciphertext · 412 bytes · rev 7 — and nothing else\n\nYour key is born on your device\n\nThe vault key is generated in your browser and never sent to CardGo. No copy, no escrow, no reset.\n\nAES-256-GCM, a key per card\n\nEvery card gets its own content key, sealed with the platform’s audited crypto before it is uploaded.\n\nOur servers hold ciphertext\n\nWe sync opaque blobs, sizes, and timestamps. Nobody at CardGo can read a card — there is no key to read it with.\n\nA recovery phrase only you hold\n\nSetup shows a 15-word phrase once and asks you to confirm it. We never store it, so only you can restore a vault.\n\nEncryption protects your cards from us — it cannot protect what you deliberately send to an AI provider. Once you attach a card, that context is governed by that provider’s terms. [Read the full privacy policy](/privacy).\n\nEarly access\n\nInstall the extension, build your first context card, and bring it to your next AI conversation.\n\nFree early access · No credit card", "url": "https://wpnews.pro/news/show-hn-cardgo-reusable-end-to-end-encrypted-context-cards-for-ai-chats", "canonical_source": "https://cardgo.ai", "published_at": "2026-08-30 16:03:23+00:00", "updated_at": "2026-08-30 16:22:02.286013+00:00", "lang": "en", "topics": ["ai-products", "ai-tools", "ai-safety"], "entities": ["CardGo", "Chrome", "ChatGPT", "Claude", "Gemini", "Perplexity", "Grok"], "alternates": {"html": "https://wpnews.pro/news/show-hn-cardgo-reusable-end-to-end-encrypted-context-cards-for-ai-chats", "markdown": "https://wpnews.pro/news/show-hn-cardgo-reusable-end-to-end-encrypted-context-cards-for-ai-chats.md", "text": "https://wpnews.pro/news/show-hn-cardgo-reusable-end-to-end-encrypted-context-cards-for-ai-chats.txt", "jsonld": "https://wpnews.pro/news/show-hn-cardgo-reusable-end-to-end-encrypted-context-cards-for-ai-chats.jsonld"}}