ExtrinsicFailed

Event Re-added v101 → v277, v290 → current #1

Emitted when an extrinsic fails during execution.

Useful for: developerswalletsanalyticsexchanges

The Big Picture

Transactions can fail for many reasons: insufficient balance, invalid parameters, rate limits, network conditions. ExtrinsicFailed tells you something went wrong and includes the error code. State changes are reverted, but you still pay fees (you used network resources even though the operation failed).

Why This Matters

If you assume success and it actually failed, your app is out of sync with reality. This event + the error code tells you what went wrong so you can fix it and retry. Common failures: insufficient balance, already registered, rate limited.

Example Scenario

You try to stake but ExtrinsicFailed fires with error 'NotEnoughBalanceToStake'. Your stake didn't happen. Check your available balance, then retry with an amount you can actually afford (including the transaction fee).

Common Questions

Do I still pay fees if my transaction fails?: Yes, for the computation used. You may get a partial refund if the failure was early, but don't count on it. Validate inputs before submitting to avoid waste.
How do I find out what error happened?: The dispatch_error field contains module index and error index. Look these up in the pallet's error list to get the specific error name and meaning.

Use Cases

Detect and handle failed transactions
Debug why operations didn't work
Monitor network error rates
Build retry logic for recoverable failures

How to Use This Event

→ Always check for this after submitting transactions
→ Parse the dispatch error to understand why it failed
→ Implement retry logic for transient failures

From Chain Metadata

An extrinsic failed.

Triggers

Preconditions

Extrinsic encountered an error during dispatch

Effects

Postconditions

State changes from failed extrinsic are reverted

Side Effects

Transaction fees still deducted (partial refund possible)
Error information available in dispatch error

Event Data

#	Name	Type	Description
0	dispatch_error	DispatchError	The error that caused the extrinsic to fail
1	dispatch_info	DispatchEventInfo	Information about the extrinsic dispatch

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Subscribe to ExtrinsicFailed events
api.query.system.events((events) => {
  events
    .filter(({ event }) =>
      event.section === stringCamelCase("System") &&
      event.method === "ExtrinsicFailed"
    )
    .forEach(({ event }) => {
      console.log("ExtrinsicFailed:", event.data.toHuman());
    });
});

On-Chain Activity

Emission Frequency

●●●●●● Infrastructure >50M emissions

Protocol plumbing — fires on nearly every extrinsic

#4 most emitted event

As of block 7,429,232

Version History

Version:

v101 block 1 2 args

v290 block 5,947,548 2 args Current

Runtime Info

Pallet Index: 0
Event Index: 1
First Version: v101
Current Version: v393

Back to System Events