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

# Finality rules & compatibility guarantees

> Stable's single-slot finality rules and developer guidelines for confirming transaction settlement.

Stable processes transactions within an EVM-based execution environment. When a block includes a transaction, the chain applies its effects to state and makes them immediately visible to applications, contracts, and indexers.

### Execution confirmation

A transaction is considered **confirmed** once:

* It is successfully included in a produced block
* State changes (balances, storage, events) can be observed through RPC

During the public testnet phase:

* Treat confirmed state as valid for application logic
* Use monitoring systems to track block continuity

### Settlement considerations

Stable provides single-slot finality, meaning transactions are finalized as soon as they are included in a valid block.

**For developers, this ensures:**

* Once a transaction appears in a confirmed block, its state changes are final and irreversible.
* Applications can safely rely on block inclusion as confirmation of settlement.

**Even with deterministic finality, applications handling financially sensitive flows should:**

* Verify transaction success via RPC or emitted events before proceeding with dependent actions (e.g., unlocks, redemptions).
* Implement retry and reconciliation logic for automation and batch operations to handle transient submission or RPC errors.

### Compatibility commitments

Stable intends to maintain a consistent execution surface for developers throughout testnet growth phases.

**Current commitments:**

* Stable will maintain published system module interfaces and execution behavior unless explicitly noted
* Any potentially disruptive changes will be:
  * Announced in advance
  * Documented in the Release & Change Log
  * Accompanied by migration instructions when necessary

Future updates will introduce:

* A formal compatibility policy
* Change-level classification for developer-facing features
* Clear handling guidance for version transitions