Blinks: back an app from a post

Every raise has a link made for posting: www.hyperseed.app/back/house for the house app. Behind it is a Solana Action: in a blink client (a wallet or browser extension that renders Solana Actions), the link unfolds inside the post as a small form with the raise's live state, Back 10 USDC, Back 50 USDC, Back 100 USDC and a field for any other amount. Everyone else, the X app on phones included, sees the raise's card, and a tap opens the same Back panel as the app page.

Each app page has a Share as Blink button that copies this link. It is the only link to share: the card, the Back panel and the blink all hang off it.

Same backing as the site

The blink asks the same server code as the Back panel to build the transaction: one USDC transfer from your wallet to the raise's escrow, with the Memo hyperseed:back:<app>, signed by your wallet, fee paid by you. The keeper counts backings from the escrow's transfers on Solana, so a backing from a post and a backing from the site are the same record, under the same per-wallet cap and the same 24-hour $SEED holder window. Your wallet shows the transfer and the Memo before you sign; a HyperSeed backing never asks for anything else.

When it says no

The blink answers in words instead of handing your wallet a transaction that would fail:

• the raise is not open yet, has closed, or its window has ended;
• the first 24 hours are for wallets holding 10,000 $SEED, and this wallet holds less (the message says when anyone can back);
• this wallet would go over the per-wallet cap, or the raise over its target;
• this wallet holds less USDC than the amount.

After you sign

Once Solana confirms the transaction, the blink reads it back from the chain and shows what was counted, with links to Claim, the raise page and the transaction. If the raise closes under its minimum, the keeper sends the USDC back and pays the fee.

Who sees the buttons on X

Blink clients unfold a link on X only when its host is listed as trusted in Dialect's registry of reviewed actions, and wallet support for blinks has narrowed: some wallets no longer render them at all. www.hyperseed.app is not in that registry yet. So today most people on X see the raise's card, and a tap opens the Back panel on this site, where the same backing works with any Solana wallet. The Action itself answers any client that asks: see For developers below.

For developers

The endpoints follow the Solana Actions specification 2.4. /actions.json maps /back/* to /api/actions/back/*. Every action route answers OPTIONS with CORS and sends X-Action-Version: 2.4 and X-Blockchain-Ids: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp.

GET  https://www.hyperseed.app/api/actions/back/house
     -> { type: "action", icon, title, description (live raise), links.actions: Back 10 / 50 / 100 / {amount} }

POST https://www.hyperseed.app/api/actions/back/house?amount=50
     { "account": "<your wallet>" }
     -> { type: "transaction", transaction: "<base64, unsigned>", message,
          links.next: { type: "post", href: "/api/actions/back/house/next?amount=50" } }
     -> or 4xx { "message": "This wallet holds 3.2 USDC, less than the 50 USDC to back." }

POST https://www.hyperseed.app/api/actions/back/house/next?amount=50
     { "account": "<your wallet>", "signature": "<transaction signature>" }
     -> { type: "action", title: "You backed ...", links.actions: Open Claim, View the raise, Transaction }