Encyclopedia Ethereum · Entry 275
Ethereum reorganizations: when a recent block leaves the chosen chain
In this article
At a glance
Key facts
| Fact | Detail | Source |
|---|---|---|
| Chain choice | Consensus fork choice determines the chain head a node follows. | [1] |
| Receipts | A receipt identifies the block containing the observed transaction execution. | [2] |
| Logs | RPC log data can indicate that a log was removed by a reorganization. | [2] |
Inclusion and durable settlement are different milestones
A transaction can first appear in a block near the head while consensus is still developing around that part of the chain. A competing branch can replace that recent inclusion. Finality supplies a stronger consensus milestone than first appearance.
Do not describe every wallet notification as irreversible settlement. The strength of the observation depends on the actual block and network state.
A deposit notification may need to be undone
Suppose an application credits a deposit from a newly observed log. That block is then removed by a reorganization. The application must reconcile the credit with the current chain rather than keep treating the removed event as a settled deposit.
If the transaction later appears in another block, its new position and execution result should be checked. Re-inclusion is not guaranteed solely because the original signed transaction still exists.
Track identifiers with their current block context
Keep the transaction hash, block hash and log position when processing events. The RPC removed indicator and updated receipts help an indexer distinguish a current event from one belonging to a replaced branch.
For material settlement decisions, use the appropriate finalized state and a documented reconciliation policy. This article does not prescribe one universal confirmation count for every application.
Direct answers
Questions people ask
Does a reorganization mean a transaction signature changed?
No. The chain’s inclusion history can change while the signed transaction remains the same. Its accepted block position and result must be checked again.
Can an application ignore a removed log because it saw it first?
No. A removed log describes an event from a block no longer in that accepted chain position. Applications need to reconcile their derived state.
Inspect the evidence
The answer and key facts have stable claim links. These records retain the scope and qualification when reused.
A block reorganization occurs when a node’s chosen chain changes and recent blocks are replaced by another accepted branch. Transactions from a replaced block may be included again elsewhere or remain absent; their old receipt position is no longer enough. Check the current chain and finality status, and let applications undo events from removed blocks.
Scope: Ethereum · data through 2026-10-02. Verification: verified · 2026-10-02T19:27:58.939Z.
Link to this claimChain choice: Consensus fork choice determines the chain head a node follows.
Scope: Ethereum · data through 2026-10-02. Verification: verified · 2026-10-02T19:27:58.939Z.
Link to this claimReceipts: A receipt identifies the block containing the observed transaction execution.
Scope: Ethereum · data through 2026-10-02. Verification: verified · 2026-10-02T19:27:58.939Z.
Link to this claimLogs: RPC log data can indicate that a log was removed by a reorganization.
Scope: Ethereum · data through 2026-10-02. Verification: verified · 2026-10-02T19:27:58.939Z.
Link to this claimRevision history
- — First publication after primary-source research and separate automated verification.
Source register
Sources and references
Retrieval dates and locators are recorded individually.- Ethereum proof of stakeethereum.org contributors
Consensus proposal schedule, voting and finality distinctions.
Locator: Slots; epochs; block proposals; attestations; finality · Version / scope: Documentation snapshot retrieved 2 October 2026; response hash recorded separately · Retrieved: 2026-10-02T18:55:26.560ZOpen source - Ethereum JSON-RPC APIethereum.org contributors
RPC requests explicitly identify addresses and block scope; receipts and removed log fields support verification examples.
Locator: eth_getBalance; eth_getTransactionReceipt; block parameter; logs · Version / scope: Documentation snapshot retrieved 2 October 2026; response hash recorded separately · Retrieved: 2026-10-02T18:55:24.990ZOpen source
Research and drafting use AI assistance. A separate automated review checks claims against primary sources; no external expert or named human review is implied. Publication, substantive editing, source retrieval and verification are recorded separately. This version was independently checked by an automated reviewer on 2 October 2026.
Editorial method and correctionsDegrees of Satoshi editorial project. “Ethereum reorganizations: when a recent block leaves the chosen chain.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/ethereum-block-reorganizations/