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The Grid API provides an invitation system that allows platform customers to invite others to create accounts and receive payments. This guide explains how to use the invitation system effectively.
See the full UMA invitations guide for details outside of the context of the Grid API.

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Overview

The invitation system enables:
  • Platform users to create invitations with optional payments for others
  • Direct prospects to sign up for your services by claiming an invitation to receive payment
  • Tracking of invitation status (pending, claimed, expired)
  • Webhook notifications when invitations are claimed

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Setup

Before starting your implementation, we recommend configuring UMAs and invitations in the dashboard. You will need to provide:
  • A name and a logo to be displayed in the invitation page.
  • A list of countries you operate UMA in.
  • An onboarding URL for people who want to create an account with you (this URL must support invitation codes). Example: http://myplatform.com/uma?code=INVITATION_CODE
  • A webhook URL to get notified when your invitations get claimed.

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Creating Invitations

To create an invitation, make a POST request to /invitations with the inviter’s UMA address: 
curl -X POST "https://api.lightspark.com/grid/2025-10-13/invitations" \
  -H "Authorization: Basic $GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "inviterUma": "$inviter@uma.domain",
    "expiresAt": "2024-12-31T23:59:59Z"
  }'
The response will include a unique invitation code that can be shared with the invitee: 
{
  "code": "019542f5",
  "createdAt": "2023-09-01T14:30:00Z",
  "inviterUma": "$inviter@uma.domain",
  "url": "https://uma.me/i/019542f5",
  "status": "PENDING"
}
The url field is the URL where the invitee can claim the invitation. For example, for the response above, you might want to generate a share message for the user with text like: “Get an UMA address so that I can send you some money! https://uma.me/i/019542f5”. The inviter can then share this URL with the invitee. When the invitee clicks the URL, they will be presented with a list of UMA providers available in their region. The invitee can select one of the providers and onboard to create their UMA address. The Grid API supports a “pay-by-link” feature that allows users to create invitations that include a payment amount. This is useful for scenarios where you want to send money to someone who doesn’t yet have a UMA address or where the sender doesn’t know the receiver’s UMA address. They can simply share a link via email, SMS, whatsapp, or other channels to send money. To create a pay-by-link invitation, include the amountToSend field when creating the invitation: 
curl -X POST "https://api.lightspark.com/grid/2025-10-13/invitations" \
  -H "Authorization: Basic $GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "inviterUma": "$inviter@uma.domain",
    "amountToSend": 5000,
    "expiresAt": "2024-12-31T23:59:59Z"
  }'
Assuming the user’s currency is USD, this example creates an invitation that will send $50 USD to the invitee when they claim it. The response will include the payment amount in the invitation details: 
{
  "code": "019542f5",
  "createdAt": "2023-09-01T14:30:00Z",
  "inviterUma": "$inviter@uma.domain",
  "url": "https://uma.me/i/019542f5",
  "status": "PENDING",
  "amountToSend": {
    "amount": 5000,
    "currency": {
      "code": "USD",
      "name": "United States Dollar",
      "symbol": "$",
      "decimals": 2
    }
  }
}
When the invitee claims the invitation, your platform will receive an INVITATION_CLAIMED webhook. At this point, you should:
  1. Check the amountToSend field in the webhook payload
  2. Create a quote for the payment amount (sender-locked)
  3. Execute the payment to the invitee’s UMA address
Note that the actual sending of the payment must be done by your platform after receiving the webhook. If your platform either does not send the payment or the payment fails, the invitee will not receive the amount. The amountToSend field is primarily used for display purposes on the claiming side of the invitation. These payments can only be sender-locked, meaning that the sender will not know ahead of time how much the receiver will receive in their local currency. The exchange rate will be determined at the time the payment is executed. If you’d like, you can also send a push notification to your sending user when you receive the INVITATION_CLAIMED webhook and have them approve the payment interactively instead.

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Best practices

  1. Always set an expiration time for invitations with a payment amount to avoid huge swings in expected exchange rates or leaked links.
  2. Allow the inviter to cancel the invitation if they want to avoid sending a payment to the wrong person if the link is leaked.
  3. Notify the inviter when the invitation is claimed so that they can see the amount received by the invitee.

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Claiming Invitations

Once onboarding (or login from an invite link) is complete, the invitee’s new VASP (which may or may not be the same as the inviter’s Grid API platform) will need to claim the invitation by making a POST request to /invitations/{invitationCode}/claim including the invitee’s newly-created UMA address: 
curl -X POST "https://api.lightspark.com/grid/2025-10-13/invitations/019542f5/claim" \
  -H "Authorization: Basic $GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "inviteeUma": "$invitee@uma.domain"
  }'
A successful claim will:
  1. Associate the invitee’s UMA address with the invitation
  2. Change the invitation status from PENDING to CLAIMED
  3. Trigger an INVITATION_CLAIMED webhook to notify the inviter’s platform of the claim

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Cancelling Invitations

To cancel a pending invitation, make a POST request to /invitations/{invitationCode}/cancel: 
curl -X POST "https://api.lightspark.com/grid/2025-10-13/invitations/019542f5/cancel" \
  -H "Authorization: Basic $GRID_CLIENT_ID:$GRID_CLIENT_SECRET"
A successful cancellation will:
  1. Change the invitation status from PENDING to CANCELLED
  2. Make the invitation URL show as cancelled when accessed
  3. Prevent the invitation from being claimed
Only the inviter or platform can cancel an invitation, and only pending invitations can be cancelled. Attempting to cancel an invitation that is already claimed, expired, or cancelled will result in an error. Example error response for an already claimed invitation: 
{
  "code": "invitation_already_claimed",
  "message": "This invitation has already been claimed and cannot be cancelled",
  "details": {
    "status": "CLAIMED",
    "inviteeUma": "$invitee@uma.domain"
  }
}

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Invitation Status

An invitation can be in one of four states:
  • PENDING: The invitation has been created but not yet claimed
  • CLAIMED: The invitation has been successfully claimed by an invitee
  • EXPIRED: The invitation has expired and can no longer be claimed
  • CANCELLED: The invitation has been cancelled by the inviter or platform
You can check the status of an invitation at any time by making a GET request to /invitations/{invitationCode}.

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Webhook Integration

When an invitation is claimed, the Grid API will send an INVITATION_CLAIMED webhook to your configured webhook endpoint. This allows you to:
  • Track invitation usage and conversion rates
  • Apply referral bonuses or rewards to the inviter
  • Update your UI to reflect the claimed status
Example webhook payload: 
{
  "invitation": {
    "code": "019542f5",
    "createdAt": "2023-09-01T14:30:00Z",
    "claimedAt": "2023-09-01T15:45:00Z",
    "inviterUma": "$inviter@uma.domain",
    "inviteeUma": "$invitee@uma.domain",
    "url": "https://uma.me/i/019542f5",
    "status": "CLAIMED"
  },
  "timestamp": "2023-09-01T15:45:00Z",
  "webhookId": "Webhook:019542f5-b3e7-1d02-0000-000000000008",
  "type": "INVITATION_CLAIMED"
}
See the Webhooks Guide for more information about webhook security and implementation.

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Best Practices

  1. Expiration Times: Consider setting appropriate expiration times for invitations based on your use case
  2. User Experience: Provide clear feedback to users about invitation status and next steps
  3. Monitoring: Track invitation metrics to understand user acquisition patterns

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Error Handling

Common error scenarios to handle:
  • Invalid invitation code
  • Expired invitation
  • Already claimed invitation
  • Rate limit exceeded
  • Missing required fields
Example error response: 
{
  "code": "invitation_expired",
  "message": "This invitation has expired and cannot be claimed",
  "details": {
    "expirationTime": "2023-08-31T23:59:59Z"
  }
}
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