> ## Documentation Index
> Fetch the complete documentation index at: https://docs.portalhq.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Update gas sponsorship for a chain

> Updates the maximum gas allowance limit for a specific chain's gas sponsor.
The `value` parameter is in ETH/SOL units.

**Note:** Gas sponsorship must be enabled for your Portal environment.




## OpenAPI

````yaml /openapi/custodian-api.yaml patch /custodians/me/gas-sponsorship/chains/{chainId}
openapi: 3.1.0
info:
  title: Portal Custodian API
  version: '3.0'
  description: >
    The Portal Custodian API provides endpoints for managing clients, building
    transactions,

    retrieving wallet data, managing delegations, alert webhooks and gas
    sponsorship, and

    reading the Portal Dashboard audit log.

    All endpoints require authentication via a Portal API Key (also known as a
    Custodian API Key)

    passed as a Bearer token.


    ## Base URL

    `https://api.portalhq.io/api/v3`


    ## Authentication

    Include your Portal API Key as a Bearer token in the `Authorization` header
    of every request.


    ## Chain ID Format

    Chain parameters use either friendly names (e.g. `ethereum`, `solana`) or
    CAIP-2 format

    (e.g. `eip155:1`, `solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp`). When using
    CAIP-2 format

    in URLs, ensure the colon is URI-encoded (`%3A`).
servers:
  - url: https://api.portalhq.io/api/v3
    description: Production
security:
  - bearerAuth: []
tags:
  - name: Clients
    description: Create and manage Portal clients
  - name: Transactions
    description: Build and evaluate blockchain transactions
  - name: Wallet Metadata
    description: Retrieve wallet balances and NFTs
  - name: Wallet Shares
    description: Manage backup shares and wallet ejection
  - name: Delegations
    description: Manage token delegations and delegated transfers
  - name: Session Keys
    description: Build and send EIP-7702 session key user operations
  - name: Alert Webhooks
    description: Manage alert webhooks, external addresses, and replay failed events
  - name: Gas Sponsorship
    description: View and manage gas sponsorship across chains
  - name: Due
    description: Manage Due webhook endpoints and deliveries
  - name: Audit Events
    description: Read the audit log of actions taken in the Portal Dashboard
paths:
  /custodians/me/gas-sponsorship/chains/{chainId}:
    patch:
      tags:
        - Gas Sponsorship
      summary: Update gas sponsorship for a chain
      description: >
        Updates the maximum gas allowance limit for a specific chain's gas
        sponsor.

        The `value` parameter is in ETH/SOL units.


        **Note:** Gas sponsorship must be enabled for your Portal environment.
      operationId: updateGasSponsor
      parameters:
        - $ref: '#/components/parameters/chainId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/UpdateGasSponsorRequest'
            example:
              value: '10'
      responses:
        '200':
          description: Gas sponsor updated successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GasSponsorChainResponse'
              example:
                chainId: eip155:11155111
                currentPeriod:
                  gasAllowanceLimit: '499'
                  gasUsage: '0.35080714673101143'
                  transactionCount: '3005'
                  endsAt: '2026-02-13T17:49:43.000Z'
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Unauthorized - invalid or missing authentication token
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  parameters:
    chainId:
      name: chainId
      in: path
      required: true
      description: >
        The CAIP-2 chain ID. Be sure the colon (`:`) is URI-encoded as `%3A` in
        the URL.
      schema:
        type: string
      examples:
        sepolia:
          value: eip155:11155111
          summary: Ethereum Sepolia
  schemas:
    UpdateGasSponsorRequest:
      type: object
      required:
        - value
      properties:
        value:
          type: string
          description: The new maximum gas allowance limit in ETH/SOL units.
    GasSponsorChainResponse:
      type: object
      properties:
        chainId:
          type: string
        currentPeriod:
          type: object
          properties:
            gasAllowanceLimit:
              type: string
            gasUsage:
              type: string
            transactionCount:
              type: string
              description: |
                Stringified integer count of sponsored transactions in the
                current period.
            endsAt:
              type: string
              format: date-time
        gasSponsor:
          nullable: true
          description: |
            Only present on Solana entries. `null` when no gas sponsor has
            been configured for that chain yet. The `balance` and
            `balanceInBaseUnits` fields are `null` when the RPC balance
            lookup fails (the sponsor address is still returned).
          type: object
          properties:
            address:
              type: string
              description: The gas sponsor's on-chain address.
            balance:
              type: string
              nullable: true
              description: |
                Human-readable native-token balance (e.g. SOL on Solana),
                formatted from `balanceInBaseUnits` using the chain's
                decimal precision.
            balanceInBaseUnits:
              type: string
              nullable: true
              description: |
                Stringified integer balance in the chain's base units
                (lamports on Solana).
    ErrorResponse:
      type: object
      properties:
        error:
          type: string
          description: Error message describing what went wrong
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: |
        Portal API Key (Custodian API Key). Pass as a Bearer token in the
        Authorization header.

````

This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.