Sponsored Gas for Belong CheckIn On-Chain Actions

What it does

Belong CheckIn Sponsored Gas lets eligible users complete supported on-chain actions without holding the network's native gas token. It is for users completing supported NFT mints, check-in payments, or eligible promoter reward withdrawals when sponsorship is enabled and the exact operation qualifies.

Sponsored Gas covers the technical network cost of an eligible blockchain transaction. It does not cover the item, ticket, NFT, or venue payment amount. If a flow includes a paid amount, the user still needs funds for that payment or can use the available card flow.

Gas and a purchase are separate costs. For an eligible NFT mint with an ERC-20 price, sponsorship can cover gas for authorisation and minting when enabled, while the user pays the NFT price in the token. For a check-in card flow, sponsorship covers gas for the ERC-20 authorisation, while the user pays through the checkout widget. A native-priced NFT mint is not sponsored in the documented beta flow, so the user pays both the native value and gas.

Eligible promoter reward withdrawals work differently because there is no purchase amount. When a venue sponsor enables the flow, Belong may submit the withdrawal transaction and charge the sponsor's gas bank for network gas; the rewards come from the venue campaign balance.

How it works

Start a supported on-chain action. Documented examples include an NFT mint, a check-in payment, and an eligible promoter reward withdrawal. Belong CheckIn shows the gasless flow and checks whether sponsorship is available.
Sign the operation. The user signs with the wallet being used and remains responsible for any item, ticket, NFT, or venue payment amount.
Resolve the sponsor. The frontend does not choose the sponsor wallet or amount to deduct. Belong API resolves the sponsor from the venue or collection.
Validate eligibility. The API checks that the signed-in user owns the wallet, sponsorship is enabled, and the operation type, token, spender, and amount match. It also checks permissions, settings, and limits.
Reserve the budget. Belong reserves budget before spending so the same balance cannot be used twice in parallel.
Submit the approved operation. Gas is sponsored on-chain only after server-side authorisation of the exact operation. A shared gas bank funds the sponsored gas.
Record actual usage. After the receipt, only the gas actually used is recorded against the sponsorship ledger.
Pay any separate amount. Sponsorship does not pay a venue or collection purchase. The user pays the applicable NFT price, payment amount, or checkout amount.

The responsibilities are separated. The user signs and pays any purchase amount. Belong CheckIn presents the gasless flow, checks availability, and submits the operation. Belong API maintains the sponsorship ledger and checks permissions, settings, and limits. The gas sponsor sponsors gas after server authorisation, and the shared gas bank funds it.

Who it's for and when to use it

Sponsored Gas is for eligible users who need to complete a supported on-chain action but do not hold the network's native gas token. It applies when a supported NFT mint or check-in payment uses an eligible flow and the venue or collection has enabled sponsorship.

During the documented beta, an NFT mint with an ERC-20 price can receive sponsorship for authorisation and minting when enabled and eligible. The user still pays the NFT price in the token. An NFT mint with a native price is not sponsored, so the user needs the native value and gas.

For check-in, the card flow sponsors gas for ERC-20 authorisation while payment happens through the checkout widget. The wallet flow supports approved low-gas ERC-20 cases, while the user pays the payment amount. Promoter reward withdrawal gas can be sponsored when the venue sponsor enables it.

Sponsored Gas does not change the ticket format or payment route. Belong CheckIn supports regular non-NFT tickets and NFT tickets. Regular ticket card payments use Stripe Connect, while NFT purchases use the configured NFT checkout partner and can accept cards where enabled. Venue payment-request QR codes are a separate payment flow. Sponsorship covers eligible network gas, not the ticket, purchase, or payment amount.

The card route also does not make every ticket an NFT. A regular ticket can use Stripe Connect without an NFT collection. An NFT ticket uses the configured NFT checkout partner, and available card or crypto methods depend on that partner, network, and collection configuration.

At the event

A guest reaches a supported check-in payment that requires an ERC-20 authorisation. Belong CheckIn checks whether Sponsored Gas is available, and the guest signs the operation with the wallet they own. Belong API resolves the venue or collection sponsor, validates the wallet, settings, operation type, token, spender, and amount, and reserves the budget.

After server authorisation, the gas sponsor covers the network gas for the ERC-20 authorisation. The guest still completes the payment through the checkout widget. Once the receipt is available, the ledger records only the gas actually used.

Belong has not paid the guest's purchase in this scenario. It has sponsored the eligible network cost while the checkout payment remains the guest's responsibility. If the guest were buying a native-priced NFT instead, the documented beta flow would not sponsor it; the guest would need both native value and gas.

Get started

Read the Sponsored Gas documentation to review supported beta flows, participant responsibilities, and server-side safety checks.

Confirm that the relevant venue or collection enables sponsorship and that the operation is an eligible case. Keep network gas separate from the purchase amount: sponsorship covers approved gas, while the user pays any item, ticket, NFT, or venue payment amount.

Open Belong CheckIn to access the event product.

FAQ

Does Sponsored Gas pay for a ticket or NFT?

No. Belong sponsors only eligible network gas. The user still pays any item, ticket, NFT, or venue payment amount. For a paid flow, the user needs funds for the payment or can use the available card flow.

Which actions can receive Sponsored Gas during beta?

The beta scope includes eligible ERC-20-priced NFT mint authorisations and mints, ERC-20 authorisation in the check-in card flow, approved low-gas ERC-20 check-in wallet cases, and promoter reward withdrawals when enabled. Native-priced NFT mints are not sponsored.

How does Belong control sponsored gas spending?

Belong validates sponsorship on the server. The API resolves the sponsor, checks wallet ownership and operation details, reserves budget before spending, approves the exact operation, and records only actual gas usage after the receipt.