> For the complete documentation index, see [llms.txt](https://docs.swapper.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.swapper.finance/getting-started/core-concepts.md).

# Core Concepts

A short tour of the ideas the rest of the docs assume. If you've read [How Swapper Works](/getting-started/how-swapper-works.md), this fills in the vocabulary.

## Integrator

You. An **integrator** is any app that embeds the Swapper widget. Each integrator has a registered **`integratorId`** that ties a session to your configuration, your fee arrangement, and your webhook endpoint. Contact Swapper to get one (see [Support](/resources/support.md)).

## Destination

The **destination** is the outcome you want, described by three values:

* **`dstChainId`** — the chain funds arrive on.
* **`dstTokenAddr`** — the token you receive there (`0x0…0` = native).
* **`depositWalletAddress`** — the wallet that receives it.

No matter what the user pays with, Swapper normalizes it to this destination.

## Source

What the user actually pays with — a card charge, USDC on Arbitrum, ETH on Ethereum, SOL on Solana, etc. Sources span **multiple ecosystems** (EVM, Solana, and more). The set of sources that can reach a given destination is determined by Swapper's routing engine.

## Deposit methods

The three ways a user can fund, chosen on the widget's home screen:

| Method          | Key               | In short                                   |
| --------------- | ----------------- | ------------------------------------------ |
| Pay with card   | `depositWithCash` | Fiat on-ramp → crypto → your token         |
| Transfer crypto | `transferCrypto`  | One-tap smart-wallet deposit & swap        |
| Wallet deposit  | `walletDeposit`   | Send from the user's own wallet, any chain |

You can show all of them or restrict the set with [`supportedDepositOptions`](/widget-integration/configuration.md#supporteddepositoptions). See [Deposit Methods](/deposit-methods/overview.md) for the details of each.

## Route

For crypto funding, Swapper computes a **route**: the cheapest/best path to swap and (if needed) bridge the source into the destination token. A route quote includes the estimated and minimum output, the fees, and the exact transactions to sign.

## The deposit record

Every completed funding produces a **deposit** — a unified record that captures the source asset, the destination asset, the tx hashes involved, and a lifecycle `status`. It's what you receive in a [webhook](/tracking-deposits/webhooks.md). Its `method` is one of `onramp`, `smart_wallet`, or `dex_swap`.

## Two notification channels

Swapper tells your app a deposit happened in two independent ways:

* [**Widget events**](/tracking-deposits/widget-events.md) — a `postMessage` to the parent page, in the browser, the instant it succeeds.
* [**Webhooks**](/tracking-deposits/webhooks.md) — a signed HTTP callback to your server when the deposit completes.

Use the event for instant UX and the webhook as your reliable source of truth.

## Amounts are base-unit strings

Everywhere Swapper reports a token amount — in webhooks, in events — it is the **integer amount in the token's smallest unit, serialized as a string**: wei for 18-decimal tokens, `1_000_000` for 1 USDC (6 decimals), lamports for Solana. Never a float. Parse with a big-integer library. Prices and USD values are decimal strings.

## The widget is hosted; you embed it

The deposit UI is a hosted app at [`https://deposit.swapper.finance`](https://deposit.swapper.finance). Your integration loads it in a sandboxed iframe via the [iframe SDK](/widget-integration/iframe-sdk.md), configured with the same four required parameters. See [Choosing an Integration](/widget-integration/choosing-an-integration.md).