# Symbiosis sTokens and Supported Chains

## sToken Introduction

The Symbiosis protocol employs sTokens, which stand for synthetic or synthesized tokens. These tokens facilitate cross-chain operations. Despite their resemblance to wrapped tokens, we purposefully refrain from labeling them as such. This distinction ensures they are set apart from the myriad of wrapped tokens prevalent in the DeFi sector.

<details>

<summary>What is wrapped token?</summary>

If you would like to refresh your knowledge about wrapped tokens, here is some basic information.

Wrapped tokens play several crucial roles in the DeFi ecosystem. Since different blockchains have different technical specifications, not all tokens can interact with all platforms. Wrapping tokens allows them to be used on platforms where they couldn't be used otherwise.

A wrapped token in decentralized finance (DeFi) is a type of token that represents an asset hosted on the same or different blockchain. It's called "wrapped" because the original asset is put into a wrapper, or a different blockchain layer. The process of wrapping and unwrapping tokens is typically done through certain organizations or smart contracts, depending on the specific wrapped token.

For example, one of the most popular wrapped tokens is Wrapped Bitcoin (WBTC). WBTC is a token on the Ethereum blockchain that represents Bitcoin. Each WBTC is backed 1:1 with a real Bitcoin. This allows Bitcoin to be used directly in Ethereum's ecosystem, enabling it to be utilized in Ethereum's DeFi applications, smart contracts, and DApps.

In order to assure the token's credibility, the equivalent amount of the underlying asset is usually locked in a smart contract or held by a custodian, which can be audited to confirm that each wrapped token is fully backed.

</details>

## **Transit Tokens: Choice of Tokens for Synthesis**

While Symbiosis has the capability to take any token from one blockchain and mint a synthetic counterpart on another, the protocol primarily engages with a select group: namely stablecoins, WETH (Wrapped ETH), and WBTC (Wrapped BTC).&#x20;

{% hint style="info" %}
**Transit tokens:** WBTC, WETH and specific stablecoins can be seen as transit tokens in the Symbiosis protocol, since they are used to enable cross-chain operations within the protocol.
{% endhint %}

But why the focus on just stablecoins, WETH and WBTC? The core objective of Symbiosis is to enable token exchanges across various blockchains. To fulfill this, the protocol prioritizes tokens that maintain consistent value and enjoy wide usage across all supported blockchains. The tokens that meet these criteria are stablecoins, WETH, and WBTC.

In cases where multiple stablecoins are present on a blockchain, the Symbiosis protocol typically leans towards one, often opting for USDC, or USDT, based on the specific blockchain.

## **sTokens Usage**

### Stablecoins

Let's consider an example: we want to exchange USDC from Ethereum for BUSD on the BNB chain via the Symbiosis protocol.&#x20;

The simplified algorithm of the bridging stablecoins is shown in Scheme 1 below.

<figure><img src="https://1179234091-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MbqmbXNUH5sa4BvYwD0%2Fuploads%2F6JMwLqn9HBZQALDXx7vn%2FV2%20swaps%20and%20Octopools-Bridging.png?alt=media&#x26;token=677bebb5-cda0-4e10-a48e-6b2420f369ec" alt=""><figcaption><p>Scheme 1. Mint-burn routing during a cross-chain operation performed via the Symbiosis protocol.</p></figcaption></figure>

Thus, when sending 1 USDC on Ethereum, we would expect to receive 1 BUSD on the BNB chain in an ideal world without transaction fees or varying exchange rates. However, in reality, the amount received will likely be slightly less than the amount sent.

### WETH

If we exchange WETH from Ethereum for WETH on Arbitrum, the bridging procedure will be the same with one exception: Octopool with sWETH will be used (Scheme 2).

<figure><img src="https://1179234091-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MbqmbXNUH5sa4BvYwD0%2Fuploads%2FMr2yxpAyMNRBrfkhi4QH%2FV2%20swaps%20and%20Octopools-Bridging%202.png?alt=media&#x26;token=baddd416-0b05-405d-9639-e4f597428cc5" alt=""><figcaption><p>Scheme 2. Mint-burn routing during a cross-chain operation performed via the Symbiosis protocol.</p></figcaption></figure>

Thus, when sending 1 WETH on Ethereum, we would expect to receive 1 WETH on Arbitrum in an ideal world without transaction fees or varying exchange rates. However, in reality, the amount received will likely be slightly less than the amount sent.

### WBTC

If we exchange WBTC from Ethereum for syBTC on zkSync Era, the bridging procedure will be the same with one exception: Octopool with sBTC will be used (Scheme 3).

<figure><img src="https://1179234091-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MbqmbXNUH5sa4BvYwD0%2Fuploads%2FY5CVvqQRmKJ2G4j7Bzix%2FV2%20swaps%20and%20Octopools-Bridging%203.png?alt=media&#x26;token=82b65098-58bd-42a5-92bf-c050b84c39ba" alt=""><figcaption><p>Scheme 2. Mint-burn routing during a cross-chain operation performed via the Symbiosis protocol.</p></figcaption></figure>

Thus, when sending 1 WBTC on Ethereum, we would expect to receive 1 syBTC on zkSync Era in an ideal world without transaction fees or varying exchange rates. However, in reality, the amount received will likely be slightly less than the amount sent.

**NB on Symbiosis Host Chain**

The Symbiosis contracts with mint-burn logic and Symbiosis Octopools are located on the Symbiosis host chain.&#x20;

{% hint style="info" %}
sTokens are used for technical purposes only, and end-users cannot trade sTokens, although they can receive sTokens when adding/removing liquidity to/from Symbiosis Octopool.

Comprehensive information on Octopools can be found here: [symbiosis-octopools](https://docs.symbiosis.finance/crosschain-liquidity-engine/symbiosis-octopools "mention").
{% endhint %}

## Supported Blockchains

The Symbiosis protocol supports the following blockchains:

1. Abstract
2. ApeChain
3. Arbitrum Nova
4. Arbitrum One
5. Avalanche
6. B² Network
7. Bahamut
8. Base
9. Berachain
10. Bitcoin
11. Blast
12. BNB
13. Boba Ethereum
14. CORE
15. Cronos
16. Cronos zkEVM
17. Ethereum
18. Fraxtal
19. Gnosis
20. Goat
21. Gravity
22. HyperEVM
23. Katana
24. KAVA EVM
25. Linea
26. Manta
27. Mantle
28. Merlin
29. Metis
30. Mode
31. Morph
32. opBNB
33. Optimism
34. Plasma
35. Polygon
36. Polygon zkEVM
37. Rootstock
38. Scroll
39. Sei v2
40. Solana
41. Soneium
42. Sonic
43. Symbiosis (Host Chain)
44. Taiko
45. Telos
46. TON
47. Tron
48. Unichain
49. ZetaChain
50. ZkLink
51. ZkSync Era

The list may be slightly outdated. To access the most relevant information, simply call the [/v1/chains](https://api.symbiosis.finance/crosschain/docs/#/Chains/get_v1_chains) method.

<figure><img src="https://1179234091-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MbqmbXNUH5sa4BvYwD0%2Fuploads%2FrnhgdhGpgcS5txKj4RJ0%2FSupported%20chains-Graph%202.png?alt=media&#x26;token=39193e6d-2499-44cc-a943-263774082905" alt=""><figcaption><p>Scheme 2. Blockchains supported by Symbiosis.</p></figcaption></figure>

## More Information

* There is an explanation of how sTokens get minted and burned: [synthesizing-process](https://docs.symbiosis.finance/crosschain-liquidity-engine/synthesizing-process "mention")