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A payment link is a reusable page at https://usetendr.tech/pay/<your-store>/<link>. The payer opens it, sees what they are paying for, and presses Pay. Tendr then opens the normal checkout, so everything else works as it does for a session your own site creates: quotes, gasless payments, refunds, webhooks and payouts to your account. Tendr never holds the money. Make links with the API (POST /v1/payment_links, see the reference), the TypeScript SDK or the dashboard. An open link can set min_amount to raise its floor. It cannot lower it.

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Currencies and the $1 minimum

A link is priced in USD or in an ISO 4217 currency Tendr has a rate for (for example EUR, NGN, JPY). The order is converted to USD when the payer presses Pay, and the currency’s own decimals apply (JPY has none). Every link takes at least $1.00 USD equivalent, checked on the link amount before fees:
  • A fixed amount is checked when you create or edit the link, and again when the payer presses Pay, because rates move. A link priced near the floor can start refusing payments later.
  • An open amount is checked when the payer presses Pay. The page shows the effective minimum: the larger of your min_amount and the $1.00 floor in the link’s currency.
  • Below the minimum the API answers 400 AMOUNT_TOO_LOW with details.min_amount.
  • When a non-USD rate is not available the API answers 503 FX_RATE_UNAVAILABLE. Try again shortly.

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Who pays the fees

fee_payer and gas_payer are optional on a link. Leave them unset (null) and the link follows your store defaults. Set them and they apply to every payment through that link. gas_max_usd caps the network fee Tendr will sponsor for the link. A session’s own setting still wins when your code creates the session. See gasless payments and the gas policy.

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The payer’s note

With note: "optional" (the default) the payer can leave a short message with the payment. Set note: "off" to hide the box.
  • At most 280 characters of plain text. Control characters are removed and whitespace is collapsed.
  • It is stored on the session and returned as payer_note on every session event (see webhooks). It is always shown as text and links in it are never clickable.
  • The email you get for a payment names the link and quotes the note.

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Test mode

Test and live links are separate. A link made with a test key has a url that ends in ?mode=test. Without ?mode=test only live links resolve, so a test link never answers on the live address. Test links use test checkout: no real money moves.

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QR codes and preview cards

Each link has a QR code at its qr_url: /pay/<store>/<link>/qr (PNG, 1024 px). Add format=svg for SVG. It encodes the link’s address, including ?mode=test for a test link. Pasting the link into a chat or a social post shows a 1200 x 630 preview card with your store name, the title, the price and your logo. The logo appears only when Tendr hosts it; otherwise the card shows your store’s initial.

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Switching off, archiving, limits

A link is never deleted: its payments and totals stay. The slug is part of the shared address and cannot be changed after creation. To retire an address, archive the link and make a new one. PATCH accepts null to clear expires_at, max_uses, description, min_amount, fee_payer, gas_payer and gas_max_usd. Omit a key to leave it as it is. Unknown keys are rejected.

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How max_uses works

max_uses is safe for single-use invoices. Every open session reserves one use, so two payers cannot both start paying a link that has one use left. A session waiting for its deposit holds the use until it expires. Once the deposit has arrived, the session holds the use until the payment settles or fails, even if that runs past the session’s expiry.
  • While a payer is mid-payment on the last use, a second payer gets 409 LINK_RESERVED: “Someone is paying this link right now, try again shortly.” If that session expires without a deposit, the use is free again.
  • When every use has settled, new payers get 409 LINK_UNAVAILABLE with availability: "used_up".
  • A session started from the page lives 5 minutes until the payer gets a quote, then the normal session lifetime. A payer who walks away frees the use after those 5 minutes.
  • Late deposits (money that arrives after the session is marked expired) are refunded and never count as a use.
  • Refunds do not free a use. A refunded payment stays used.
  • use_count can exceed max_uses in one narrow case: a session that is past its expiry but not yet swept receives a deposit that settles. A deposit that lands in the same millisecond the session expires can do the same, because its use was already released to the next payer.
A link accepts at most 200 open sessions that have a quote. Past that the page answers 429 LINK_BUSY. Sessions that have no quote yet do not count: they expire within minutes.

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Totals

Every link read returns: Only settled payments count towards total_paid. A refund counts towards total_refunded once it has executed on chain. To list the payments of one link, use GET /v1/payments?payment_link_id=<id>. A store that settles into its own contract (an integrator with payout mode wallet) takes payments through hooks instead. Creating a link for it returns 409 LINK_NOT_SUPPORTED.

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What the payer sees

  1. Your store name and logo, the title, the description, and the price (or an amount box).
  2. If the link is not available, a short reason (switched off, expired, used up) and no Pay button.
  3. A note box when note is optional.
  4. Pay creates the session and sends the payer to the hosted checkout to choose a token and send.
  5. After payment, the success screen links back to the payment link page.
Nothing is created until the payer presses Pay: opening or previewing a link makes no session.