> For the complete documentation index, see [llms.txt](https://docs.squidrouter.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.squidrouter.com/api-and-sdk-integration/key-concepts.md).

# Key Concepts

## Overview

These concepts are functionalities that persist throughout Squid's Widget, API, and SDK that enable a seamless cross-chain experience for both users and developer. Please read through each feature to understand how they are implemented across Squid

## Squid Functionality

The functionality of the Squid boils down to **3 main functionalities**:

1. [**Route Requests**](/old-v2-documentation-deprecated/key-concepts/get-a-route.md)**(Fetching a Route):** Calculating the most optimized path from one asset to another.
2. [**Route Execution**](/old-v2-documentation-deprecated/key-concepts/execute-the-route.md)**:** The submission and execution of that path on chain.
3. [**Transaction Status**](/old-v2-documentation-deprecated/key-concepts/track-status.md)**:** The validation that the transaction has been completed.

There are **2 advanced functionalities** that enhance Squid's API capabilities:

1. [**Transaction Hooks**](https://docs.squidrouter.com/) **(Pre/Post):** Allow transactions to be prepended(prehook) or appended(posthook) to asset transfers for a user. Think unstaking then transferring an asset or transfering an asset across chain then staking.
2. [**Collecting Fees**](/old-v2-documentation-deprecated/key-concepts/collect-fees-1.md)**:** Always integrators to collect fees associated with transactions. Note, this function is currently not available for v2 yet.

## Transaction Types

When requesting a route, the API returns a `transactionType` field that determines how the transaction should be constructed and submitted on-chain. Different source chains use different transaction types. See [**Transaction Types**](/api-and-sdk-integration/key-concepts/transaction-types.md) for the full reference.

#### **A Note On Up-Time**

Squid aims for 100% up-time with multiple guardrails in place to prevent unintended downtime. If you believe Squid may be experiencing downtime you can check our [status page ](https://status.v2.api.squidrouter.com)to see if there are any outages.


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