Background

The /v2/tx endpoints include unified APIs that broadcast transactions and provide insight into the status of transactions and their subsequent cross-chain actions over all the bridges we support.

You can use the /v2/tx endpoints to track the progress of a cross-chain transfer or swap, no matter how many chains or bridges the transfer touches, in realtime. (For more advanced use cases, the endpoints support tracking multiple distinct transfers initiated in a single transaction)

You can also use it to identify failure cases (e.g. a swap that fails due to slippage, an IBC transfer that fails due to inactive relayers) and determine where the user’s tokens will become available.

For example, if one of your end users initiates a swap that begins with ATOM on Neutron and concludes with JUNO on Juno, you can use the lifecycle tracking to report when the ATOM moves from Neutron to the Hub, when it reaches Osmosis, and when the JUNO finally arrives safely on Juno.

Basics

At a high-level, the transaction tracking works in two stages:

  1. You must inform our tracking engine that you want a particular transaction tracked by submitting it to the chain via /v2/tx/submit or submitting it to your own Node RPC then calling /v2/tx/track
  2. Query status at some regular interval to get updates on the progress of the transaction

Tracking Multiple Independent Routes

(You can use the endpoint to track multiple transfers initiated in a single transaction, where the status of transfer i is given by entry i in the transfers array. For example, I could transfer ATOM to the Cosmos Hub and OSMO to Osmosis in a single transaction and track them with transfers[0] and transfers[1] respectively)

For a single transfer that has multiple hops (e.g. transferring ATOM to the Cosmos Hub then to Osmosis), you can track the status of each hop using the entries of transfers[i].transfer_sequence

The status endpoint provides a mixture of high-level fields to keep track of the basic progress of your route and low-level fields to drill all the way into the individual transactions that make up a single transfer.

Important high-level /v2/tx/status fields

Each entry in the transfers array corresponds to a single route that may contain many steps, and each entry in transfer_sequence will contain very detailed information about each step in that route.

But there a a few high-level fields in each transfers entry that you’ll find useful no matter what your route does or what bridges it involves:

  • state: The basic status of your route. This lets you report the basic state of the route to the user (e.g. in progress, failed, etc…)
    • STATE_SUBMITTED: Indicates the transaction has been accepted for tracking but no on chain evidence has been found yet.
    • STATE_ABANDONED: Tracking has stopped after 30 minutes without progress. There is likely a relayer outage, an undetected out of gas error, or some other problem.
    • STATE_PENDING: The route is in progress and no errors have occurred yet
    • STATE_PENDING_ERROR: The route is in progress and an error has occurred somewhere, but the error is currently propagating, so the user doesn’t have their tokens returned yet. (This state will only occur for protocols that require an “acknowledgement” on the source chain to process an error. IBC only at this time)
    • STATE_COMPLETED_SUCCESS: The route has completed successfully and the user has their tokens on the destination (indicated by transfer_asset_release)
    • STATE_COMPLETED_ERROR: The route errored somewhere and the user has their tokens unlocked in one of their wallets. Their tokens are either on the source chain, an intermediate chain, or the destination chain but as the wrong asset. (Again, transfer_asset_release indicates where the tokens are)
  • next_blocking_transfer: Gives the index of the entry in transfer_sequence that corresponds to the currently propagating transfer that is immediately blocking the release of the user’s tokens — next_blocking_transfer.transfer_sequence_index (it could be propagating forward or it could be propagating an error ack backward). This lets you tell the user exactly which operation is pending at a given time
  • transfer_asset_release: Info about where the users tokens will be released when the route completes. This populates on STATE_PENDING_ERROR, STATE_COMPLETED_SUCCESS, or STATE_COMPLETED_ERROR. This lets you tell the user where to recover their funds in the event of a success or failure (If you want to better understand how to predict this or where funds might end up, see Cross-chain Failure Cases)
    • transfer_asset_release.released: Boolean given whether the funds are currently available (If state isSTATE_PENDING_ERROR , this will be false
    • transfer_asset_release.chain_id: Chain where the assets are released or will be released.
    • transfer_asset_release.denom: Denom of the tokens the user will have.

Detailed Info: Usingtransfer_sequence

The transfer_sequence array consists of TransferEvent objects, which give detailed information about an individual transfer operation. The object acts as a wrapper around one details object for each bridge we support

  • CCTPTransferInfo
  • IBCTransferInfo
  • AxelarTransferInfo
  • HyperlaneTransferInfo

Each one contains slightly different data and statuses corresponding to the details of their bridge, but they all contain some standard info:

  • from_chain_id
  • to_chain_id
  • Transactions and block explorer links for all of the significant events in the transfer (send tx, receive tx, and sometimes ack tx)
  • A status field giving the status of the transfer, which can vary based on bridge

IBC Transfer Data

The state field in the IBCTransferInfo entries in the transfer_sequence array have the following meanings:

  • TRANSFER_UNKNOWN: The transfer state is unknown.
  • TRANSFER_PENDING - The send packet for the transfer has been committed and the transfer is pending.
  • TRANSFER_PENDING_ERROR - There has been a problem with the transfer (e.g. the packet has timed out) but the user doesn’t have their funds unlocked yet because the error is still propagating
  • TRANSFER_RECEIVED- The transfer packet has been received by the destination chain. It can still fail and revert if it is part of a multi-hop PFM transfer.
  • TRANSFER_SUCCESS - The transfer has been successfully completed and will not revert.
  • TRANSFER_FAILURE - The transfer has failed.

packet_txs contain transaction hashes, chain IDs, and block explorer links for potentially 4 transactions:

  • send_tx: The packet being sent from the source chain
  • receive_tx: The packet being received on the destination chain
  • timeout_tx: The packet has being timed out on the destination chain
  • acknowledge_tx: The successful or failed acknowledgement of the packet on the source chain

Axelar Transfer Data

When one of the transfers is an Axelar transfer, the transfer_sequence array will give an axelar_transfer (AxelarTransferInfo), instead of an ibc_transfer, which contains different data because:

  • Skip Go API may utilize send_token or contract_call_with_token (two underlying Axelar protocols) depending on which is cheaper and which is required to execute the user’s intent
  • Axelar does not have a notion of packets or acks, like IBC does
  • Axelar provides a nice high level UI (Axelarscan) to track the status of their transfers

More precise details about all the fields are below:

  • type : an enum of AXELAR_TRANSFER_SEND_TOKEN and AXELAR_TRANSFER_CONTRACT_CALL_WITH_TOKEN, which indicate whether the Axelar transfer is a [Send Token](https://docs.axelar.dev/dev/send-tokens/overview) or a [Contract Call With Token](https://docs.axelar.dev/dev/general-message-passing/gmp-tokens-with-messages) transfer respectively.
  • axelar_scan_link: Gives the link to Axelar’s bridge explorer (which can help track down and unstick transactions)
  • state field indicates the current state of the Axelar transfer using the following values:
    • AXELAR_TRANSFER_UNKNOWN - The transfer state is unknown.
    • AXELAR_TRANSFER_PENDING_CONFIRMATION - The transfer has been initiated is pending confirmation by the Axelar network.
    • AXELAR_TRANSFER_PENDING_RECEIPT - The transfer has been confirmed by the Axelar network and is pending receipt at the destination.
    • AXELAR_TRANSFER_SUCCESS - The transfer has been completed successfully and assets have been received at the destination.
    • AXELAR_TRANSFER_FAILURE - The transfer has failed.
  • txs field schema depends on the type of the transfer
    • If type is AXELAR_TRANSFER_SEND_TOKEN, there are 3 txs:
      • send_tx (initiating the transfer)
      • confirm_tx(confirming the transfer on axelar)
      • execute_tx (executing the transfer on the destination)
    • If type is AXELAR_TRANSFER_CONTRACT_CALL_WITH_TOKEN:
      • send_tx (initiating the transfer)
      • gas_paid_tx (paying for the relayer gas on the source chain)
      • approve_tx (approving the transaction on Axelar - only exists when the destination chain is an EVM chain)
      • confirm_tx(confirming the transfer on Axelar - only exists when destination chain is a Cosmos chain)
      • execute_tx (executing the transfer on the destination)

CCTP Transfer Data

When one of the transfers is a CCTP transfer, the transfer_sequence array will give a cctp_transfer (CCTPTransferInfo), instead of an ibc_transfer, which contains different data because:

  • CCTP works by Circle attesting to & signing off on transfers
  • There’s no notion of an acknowledgement in CCTP

More precise details about the different/new fields are below:

  • state gives the status of the CCTP transfer:
    • CCTP_TRANSFER_UNKNOWN - Unknown error
    • CCTP_TRANSFER_SENT - The burn transaction on the source chain has executed
    • CCTP_TRANSFER_PENDING_CONFIRMATION - CCTP transfer is pending confirmation by the cctp attestation api
    • CCTP_TRANSFER_CONFIRMED - CCTP transfer has been confirmed by the cctp attestation api but not yet received on the destination chain
    • CCTP_TRANSFER_RECEIVED - CCTP transfer has been received at the destination chain
  • txs contains the chain IDs, block explorer links, and hashes for two transactions:
    • send_tx: The transaction submitted the CCTP burn action on the source chain to initiate the transfer
    • receive_tx: The transaction on the destination chain where the user receives their funds

Hyperlane Transfer Data

When one of the transfers is a Hyperlane transfer, the transfer_sequence array will give a hyperlane_transfer (HyperlaneTransferInfo), instead of an ibc_transfer, which contains different data because:

  • Hyperlane is a very flexible protocol where the notion of “approving/verifying” the transfer is undefined / up to the bridge developer to implement
  • There’s no notion of an acknowledgement in Hyperlane

More precise details about the different/new fields are below:

  • state gives the status of the Hyperlane transfer:
    • HYPERLANE_TRANSFER_UNKNOWN - Unknown error
    • HYPERLANE_TRANSFER_SENT - The Hyperlane transfer transaction on the source chain has executed
    • HYPERLANE_TRANSFER_FAILED - The Hyperlane transfer failed
    • HYPERLANE_TRANSFER_RECEIVED - The Hyperlane transfer has been received at the destination chain
  • txs contains the chain IDs, block explorer links, and hashes for two transactions:
    • send_tx: The transaction submitted the CCTP burn action on the source chain to initiate the transfer
    • receive_tx: The transaction on the destination chain where the user receives their funds

OPInit Transfer Data

When one of the transfers is a OPInit transfer, the transfer_sequence array will give a op_init_transfer (OPInitTransferInfo), instead of an ibc_transfer, which contains different data because:

  • The OPInit bridge is the Initia ecosystem’s native bridging solution facilitating transfers between Initia and the Minitias.
  • There’s no notion of an acknowledgement in the OPInit bridge

More precise details about the different/new fields are below:

  • state gives the status of the OPInit transfer:
    • OPINIT_TRANSFER_UNKNOWN - Unknown error
    • OPINIT_TRANSFER_SENT - The deposit transaction on the source chain has executed
    • OPINIT_TRANSFER_RECEIVED - OPInit transfer has been received at the destination chain
  • txs contains the chain IDs, block explorer links, and hashes for two transactions:
    • send_tx: The transaction that submitted the OPInit deposit action on the source chain to initiate the transfer
    • receive_tx: The transaction on the destination chain where the user receives their funds

Detailed Example of Typical Usage

This will walk through an example of how a developer would use the api to track the progress of a route that may include multiple

In this particular example, we’ll cover a simple 2-hop IBC transfer from axelar to the cosmoshub through osmosis.

(Usage is similar for tracking Axelar transfers or transfers that include multiple hops over distinct bridges but the data structures change slightly depending on what underlying bridge is being used)

1. Call /tx/submit to broadcast a transaction

Post a signed user transaction (that you can form using /fungible endpoints) to the /submit endpoint. The Skip Go API will handle the broadcasting of this transaction and asynchronously begin tracking the status of this transaction and any subsequent transfers.

A successful response looks like the following:

response
{
  "tx_hash": "AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9"
}

It indicates that the transaction was accepted by the Skip Go API and its status can be tracked using the returned tx_hash.

The transaction is broadcast using BROADCAST_MODE_SYNC and in the event that a transaction is rejected by the node, the /submit endpoint will return a 400 response along with the failure reason as shown below:

response
{
    "code": 3,
    "message": "insufficient fees; got: 0uosmo which converts to 0uosmo. required: 2000uosmo: insufficient fee",
    "details": []
}

Tracking a transaction that was not broadcast using /submit

If a transaction was not broadcast through the /submit endpoint and has already landed on chain, the /track endpoint can be used to initiate tracking of the transaction’s progress.

2. Call /status to query the status of the transaction and IBC transfer progress

Skip Go API continually indexes chain state to determine the state of the transaction and the subsequent IBC transfer progress. This information can be queried using the /status endpoint.

It will initially yield a response that looks like the following:

  • There’s a top-level transfers field, which gives an array where each entry corresponds to a single sequence of transfers. This does not mean there’s one entry in the transfers field for every bridging operation. In general, one transfer could consist of an arbitrarily long sequence of swaps and transfers over potentially multiple bridges. transfers is an array because one transaction can initiate potentially several distinct and independent transfers (e.g. transferring OSMO to Osmosis and ATOM to the Hub) in the same tx.
  • The state field will give STATE_SUBMITTED indicating the transaction has been accepted for tracking by the Skip Go API but no events have been indexed yet:
response
{
  transfers: [
    {
      "state": "STATE_SUBMITTED",
      "transfer_sequence": [],
      "next_blocking_transfer": null,
      "transfer_asset_release": null,
      "error": null
    }
  ]
}

Once indexing for the transaction has begun, the state will change to STATE_PENDING.

  • The status of any transfers along the transfer sequence will be returned in the transfer_sequence field as shown in the example response below.
  • The entries in the transfer_sequence correspond to transfers and will be represented by different objects depending on which bridge is being used (e.g. Axelar or IBC).
  • The next_blocking_transfer field gives some information about the next blocking transfer in thetransfer_sequence field.
    • The transfer_sequence_index indicates which transfer in the transfer_sequence field is blocking progress.
  • The transfer_asset_release field will be populated with information about the asset release as it is becomes known.
    • The chain_id and denom fields indicate the location and asset being released.
    • The released field indicates whether the assets are accessible. The transfer_asset_release field may become populated in advance of asset release if it can be determined with certainty where the eventual release will be. This will happen for example in a transfer sequence that is a PFM-enabled sequence of IBC transfers when one hop fails due to packet timeout or an acknowledgement failure. The transfer sequence will revert and the transfer_asset_release field will indicate that the assets will be released on the initial chain.
response
{
  "transfers": [
    {
      "state": "STATE_PENDING",
      "transfer_sequence": [
        {
         "ibc_transfer": {
            "src_chain_id": "axelar_dojo-1",
            "dst_chain_id": "osmosis-1",
            "state": "TRANSFER_PENDING",
            "packet": {
              "send_tx": {
                "chain_id": "axelar-dojo-1",
                "tx_hash": "AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9",
                "explorer_link": "https://www.mintscan.io/axelar/transactions/AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9"
              },
              "receive_tx": null,
              "acknowledge_tx": null,
              "timeout_tx": null,
              "error": null
            }
         }
       }
      ],
      "next_blocking_transfer": {
        "transfer_sequence_index": 0
      },
      "transfer_asset_release": null,
      "error": null
    }
  ]
}

The transfer assets will be released before all expected acknowledgements have been indexed. When the transfer sequence has reached this state, the status will be updated to STATE_RECEIVED as shown in the example response below. Note that transfer_asset_release now indicates the chain ID of the chain where the assets are released and the denomination of the released assets.

response
{
  transfers: [
    {
      "state": "STATE_COMPLETED_SUCCESS",
      "transfer_sequence": [
        {
          "ibc_transfer": {
            "src_chain_id": "axelar_dojo-1",
            "dst_chain_id": "osmosis-1",
            "state": "TRANSFER_PENDING",
            "packet": {
              "send_tx": {
                "chain_id": "axelar-dojo-1",
                "tx_hash": "AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9",
                "explorer_link": "https://www.mintscan.io/axelar/transactions/AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9"

              },
              "receive_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D"
              },
              "acknowledge_tx": null,
              "timeout_tx": null,
              "error": null
            }
          }
        },
        {
          "ibc_transfer": {
            "src_chain_id": "osmosis-1",
            "dst_chain_id": "cosmoshub-4",
            "state": "TRANSFER_SUCCESS",
            "packet": {
              "send_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D"
              },
              "receive_tx": {
                "chain_id": "cosmoshub-4",
                "tx_hash": "913E2542EBFEF2E885C19DD9C4F8ECB6ADAFFE59D60BB108FAD94FBABF9C5671",
                "explorer_link": "https://www.mintscan.io/cosmos/transactions/913E2542EBFEF2E885C19DD9C4F8ECB6ADAFFE59D60BB108FAD94FBABF9C5671"

              },
              "acknowledge_tx": null,
              "timeout_tx": null,
              "error": null
            }
          }
        }
      ],
      "next_blocking_transfer": null,
      "transfer_asset_release": {
        "chain_id": "cosmoshub-4",
        "denom": "uatom",
        "released": true
      },
      "error": null
    }
  ]
}

Once it has been determined that all packets along the transfer sequence have either been acknowledged or timed out, state will be updated to STATE_COMPLETED_SUCCESS as shown in the example response below. Note that next_blocking_transfer is now null since the transfer is complete.

response
{
  "transfers": [ 
    {
      "state": "STATE_COMPLETED_SUCCESS",
      "transfer_sequence": [
        {
          "ibc_transfer": {
            "src_chain_id": "axelar_dojo-1",
            "dst_chain_id": "osmosis-1",
            "state": "TRANSFER_SUCCESS",
            "packet": {
              "send_tx": {
                "chain_id": "axelar-dojo-1",
                "tx_hash": "AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9",
                "explorer_link": "https://www.mintscan.io/axelar/transactions/AAEA76709215A808AF6D7FC2B8FBB8746BC1F196E46FFAE84B79C6F6CD0A79C9"
              },
              "receive_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D"
              },
              "acknowledge_tx": {
                "chain_id": "axelar-dojo-1",
                "tx_hash": "C9A36F94A5B2CA9C7ABF20402561E46FD8B80EBAC4F0D5B7C01F978E34285CCA",
                "explorer_link": "https://www.mintscan.io/axelar/transactions/C9A36F94A5B2CA9C7ABF20402561E46FD8B80EBAC4F0D5B7C01F978E34285CCA"
              },
              "timeout_tx": null,
              "error": null
            }
          }
        },
        {
        	"ibc_transfer": {
            "src_chain_id": "osmosis-1",
            "dst_chain_id": "cosmoshub-4",
            "state": "TRANSFER_SUCCESS",
            "packet": {
              "send_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/082A6C8024998EC277C2B90BFDDB323CCA506C24A6730C658B9B6DC653198E3D"
              },
              "receive_tx": {
                "chain_id": "cosmoshub-4",
                "tx_hash": "913E2542EBFEF2E885C19DD9C4F8ECB6ADAFFE59D60BB108FAD94FBABF9C5671",
                "explorer_link": "https://www.mintscan.io/cosmos/transactions/913E2542EBFEF2E885C19DD9C4F8ECB6ADAFFE59D60BB108FAD94FBABF9C5671"
              },
              "acknowledge_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "1EDB2886E6FD59D6B9C096FBADB1A52585745694F4DFEE3A3CD3FF0153307EBC",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/1EDB2886E6FD59D6B9C096FBADB1A52585745694F4DFEE3A3CD3FF0153307EBC"
              },
              "timeout_tx": null,
              "error": null
            }
        	}
        }
      ],
      "next_blocking_transfer": null,
      "transfer_asset_release": {
        "chain_id": "cosmoshub-4",
        "denom": "uatom",
        "released": true
      },
      "error": null
    }
  ]
}

Any packet acknowledgement errors will be surfaced in the error field for the relevant packet as follows:

response
{
  "transfers": [
  	{
      "state": "STATE_COMPLETED_ERROR",
      "transfer_sequence": [
        {
          "ibc_transfer": {
            "src_chain_id": "osmosis-1",
            "dst_chain_id": "cosmoshub-4",
            "state": "TRANSFER_FAILED",
            "packet": {
              "send_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "112714A8144019161CAAA8317016505A9A1DDF5DA7B146320A640814DDFA41C0",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/112714A8144019161CAAA8317016505A9A1DDF5DA7B146320A640814DDFA41C0"
              },
              "receive_tx": {
                "chain_id": "cosmoshub-4",
                "tx_hash": "E7FB2152D8EA58D7F377D6E8DC4172C99791346214387B65676A723FCFC7C980",
                "explorer_link": "https://www.mintscan.io/osmosis/cosmos/E7FB2152D8EA58D7F377D6E8DC4172C99791346214387B65676A723FCFC7C98"

              },
              "acknowledge_tx": {
                "chain_id": "osmosis-1",
                "tx_hash": "8C9C1FA55E73CD03F04813B51C697C1D98E326E1C71AB568A2D23BF8AEAFFEC7",
                "explorer_link": "https://www.mintscan.io/osmosis/transactions/8C9C1FA55E73CD03F04813B51C697C1D98E326E1C71AB568A2D23BF8AEAFFEC7"

              },
              "timeout_tx": null,
              "error": {
                "code": 1,
                "message": "ABCI code: 1: error handling packet: see events for details"
              }
            }
          }
        }
      ],
      "next_blocking_transfer": null,
      "transfer_asset_release": {
        "chain_id": "osmosis-1",
        "denom": "uosmo",
        "released": true
      },
      "error": null
		}
	]
}

Any execution errors for the initial transaction will be surfaced in the error field at the top level of the response as follows:

response
 {
  "transfers": [
    {
      "state": "STATE_COMPLETED_ERROR",
      "transfer_sequence": [],
      "next_blocking_transfer": null,
      "transfer_asset_release": null,
      "error": {
        "code": 11,
        "message": "out of gas in location: Loading CosmWasm module: sudo; gasWanted: 200000, gasUsed: 259553: out of gas"
      }
    }
  ]
}

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