SPC Chain FAQ v0.5
What is SPC Chain, or SPC DEX?
SPC Chain is the blockchain initially developed by SPC and community. SPC DEX is the decentralized exchange module developed on top of the SPC Chain blockchain.
What is the design principle of SPC Chain?
The main focuses for the design of SPC Chain are:
- No custody of funds: traders maintain control of their private keys and funds.
- High performance: low latency, high throughput for a large user base, and high liquidity trading. We target to achieve 1 second block times, with 1 confirmation finality.
- Low cost: in both fees and liquidity cost.
- Easy user experience: as friendly as SPC.com.
- Fair trading: minimize front-running, to the extent possible.
- Evolvable: able to develop with forever-improving technology stack, architecture, and ideas.
What can you do on SPC Chain?
You can:
- Send and receive SPC
- Issue new tokens
- Send, receive, burn/mint and freeze/unfreeze tokens
- Propose to create trading pairs between two different tokens
- Send orders to buy or sell assets through trading pairs created on the chain
Will SPC Chain introduce more features and transaction types in the future?
Yes, SPC Chain team and community would cherish the technology advancements and recommended trends and strive to make circulation of assets and value easier and easier.
What is the native coin on SPC Chain?
The Star Pacific Coin, SPC, is the native asset on SPC Chain. There are 200MM Star Pacific Coins in total. There will be no mining. The existing coin burns and freezes will still be in effect on the new SPC Chain blockchain.
The exact number of Star Pacific Coins will be destroyed based on the same number of SPC ERC20 tokens that have already been destroyed.
Since SPC Chain is live, all SPC ERC20 tokens will be swapped for SPC Chain coins. All users who hold SPC ERC20 tokens can deposit them to SPC.com, and upon withdrawal, the new SPC Chain native coins will be sent to their new wallets.
How can I register on SPC Chain/DEX and start trading?
There is no need to register. All you need is a SPC Chain address, which can be generated with any wallet that supports SPC Chain. Then you can trade SPC or other assets stored on that address.
How can I send orders on SPC DEX?
Order
On SPC DEX, you can send "new order" messages to buy or sell certain assets. You can also send "cancel" messages to cancel existing open orders.
You can use a wallet to send new orders and cancels. SPC DEX also provides API for automated trading.
In SPC DEX v1.0, the order message contains:
- Symbol: trading pair on the chain
- Side: buy or sell
- Price: only limit price orders are supported in SPC Chain v1.0
- Amount
- Time In Force: SPC DEX supports
Immediate Or Cancel(IOC) andGood Till Expiry(GTE) orders. GTE orders can quote on the exchange until they are filled by the opposite orders satisfying the limit price, or canceled by client themselves, or expire after 72 hours after 00:00 (UTC). Check the "What isOrder Expire" section of the FAQ for more information.
Network nodes examine orders to ensure they are valid. Once the orders are accepted, they are booked on the next block, and get matched accordingly.
What is Immediate Or Cancel order?
Immediate Or Cancel is a special order type. Once the order is accepted into a block, Immediate Or Cancel orders only exist in this block round. The order may get filled to zero, or partially or fully filled by other orders, and then will become expired and removed from the order book right away. As a result, it will not be tradable in the next round of matching. A small fee will be charged for the network usage, if there is no fill at all for the order (deemed as no intention to trade).
Match
SPC DEX does all of its matching on the blockchain, i.e. all nodes perform the matches and expect the same result. This is to ensure the maximum transparency and to mitigate the chance for front-running, even from the block producers. The matching infrastructure is expected to evolve and grow in capacity as time progresses.
SPC DEX doesn't do continuous matching as most centralized exchanges do. Instead, it matches using periodic auction matching for all the existing open orders received in the past and the latest blocks. The match logic is explained in more detail later.
Trade
Once the orders are filled, the corresponding assets will be automatically moved into buyers' addresses. The confirmation is instant and no need to wait for further blocks (i.e. T+0 block). Buyers can use the bought asset right away, either send it to another address or trade it again.
What is Order Expire?
Orders accepted by SPC DEX will either get filled with other orders or remain in the order book, but they will not stay on the order book forever. These orders will expire and be removed from the order book after the 1st midnight (UTC) after 72 hours once the order gets accepted. A small fee will be charged for the network usage, if there is no fill at all for the order (deemed as no intention to trade).
Where can I see my assets and trades?
You can always use wallets that support SPC Chain to check your asset balances, open orders, and (optionally) order/trade history. SPC Chain Explorer is another tool to check balances and transactions.
When can I see my order on the blockchain after I send it?
It depends. Normally, if you connect to one of the Accelerated Nodes, your orders should get accepted and booked into a block in 1-3 seconds. If the order price is marketable, the order will be filled and trades will come back in about similar time. If you send the order from far-way (self-setup full node), or there is heavy network traffic, the order may take longer to reach a Validator (block producer).
What is the Fee Structure?
Fees are charged and shared among the block producers (i.e. Validators) to run the network, in order to pay for the network usage and prevent abuse and attack. Since all user transactions, include transfer, new order, cancel etc, they are all recorded in blocks and chain state, the fee will be shared among different transactions. New orders are exempt from fees to encourage usage and larger trades will be charged more for their benefits from the liquidity provided in the network. Order Expire and Cancel are also charged with a fee if they fail to provide any liquidity. The current fee table is here
Besides the fees, no other gas will be charged.
Fees can be paid in any asset, but the network will charge SPC first and apply a discount if the address has SPC balance.
The fee is subject to periodical review and adjustment, after agreement from validators, via a proposal-vote procedure. See a fee-change proposal here
- Trade fee is calculated based on trade notional value, while fees for other transactions are fixed.
- It is free to send a new GET order, cancel a partially filled order, or expire a partially filled order.
- Non-Trade related transactions will be charged with a fee when the transactions happen, and can only be paid in SPC. The transaction will be rejected if the address does not have enough SPC.
- Trade-related transactions will be charged with a fee when an order is filled, or canceled/expired/IOC-expired with no fills. If there is enough SPC to pay, SPC fee structure will be used, otherwise, non-SPC fee structure will be used instead.
- If the whole order value and free balance for the receiving asset are not enough to pay the fee, all the receiving asset and its residual balance will be charged.
What is the current Fee Table on SPC Chain Mainnet?
Fees are variable and may change over time as governance proposals are proposed and voted on. The current fees table for Mainnet as of 2021-03-21 is as follows:
| Transaction Type | Pay in Non-SPC Asset | Pay in SPC | Exchange (DEX) Related |
|---|---|---|---|
| New Order | 0 | 0 | Y |
| Cancel (No Fill) | Equivalent 0.00005 SPC | 0.00001 SPC | Y |
| Order Expire (No Fill) | Equivalent 0.00005 SPC | 0.00001 SPC | Y |
| IOC (No Fill) | Equivalent 0.00025 SPC | 0.000005 SPC | Y |
| Transfer | N/A | 0.000075 SPC | N |
| crossTransferOut | N/A | 0.000075 SPC | N |
| Multi-send | N/A | 0.00006 SPC | N |
| Issue Asset | N/A | 10 SPC | |
| Mint Asset | N/A | 0.002 SPC | N |
| Transfer ownership | N/A | 0.002 SPC | N |
| Burn Asset | N/A | 0.002 SPC | N |
| Freeze/Unfreeze Asset | N/A | 0.001 SPC | N |
| Lock/unlock/relock Asset | N/A | 0.002 SPC | N |
| List Asset | N/A | 200 SPC | N |
| Submit Proposal | N/A | 1 SPC | N |
| Deposit | N/A | 0.000125 SPC | N |
| Enable Memo Check | N/A | 0.2 SPC | N |
| Disable Memo Check | N/A | 0.2 SPC | N |
| HTLT | N/A | 0.000075 SPC | N |
| depositHTLT | N/A | 0.000075 SPC | N |
| claimHTLT | N/A | 0.000075 SPC | N |
| refundHTLT | N/A | 0.000075 SPC | N |
| refundHTLT | N/A | 0.000075 SPC | N |
| TinyIssueFee | N/A | 0.4 SPC | N |
| MiniIssueFee | N/A | 0.6 SPC | N |
| SetTokenUri | N/A | 0.000075 SPC | N |
| List BEP8 Token | N/A | 1 SPC | N |
| Create A New Smart Chain Validator | N/A | 2 SPC | N |
| Edit Smart Chain Validator Information | N/A | 0.2 SPC | N |
| Delegate Smart Chain Validator | N/A | 0.0002 SPC | N |
| Redelegate Smart Chain Validator | N/A | 0.0006 SPC | N |
| Undelegate Smart Chain Validator | N/A | 0.0004 SPC | N |
| Unjail A Smart Chain Validator | N/A | 0.5 SPC | N |
| Submit Byzaitine Behavior Evidence of A Smart Chain Validator | N/A | 0.5 SPC | N |
| Submit Smart Chain Proposal | N/A | 1 SPC | N |
| Smart Chain Proposal Deposit | N/A | 0.00025 SPC | N |
| Smart Chain Proposal Vote | N/A | 0 SPC | N |
| Cross transfer out relayer reward | N/A | 0.0004 SPC | N |
What is the current Fee Table on SPC Chain Testnet?
Fees are variable and may change over time as governance proposals are proposed and voted on. The current fees table for Testnet as of 2021-03-17 is as follows:
| Transaction Type | Pay in Non-SPC Asset | Pay in SPC | Exchange (DEX) Related |
|---|---|---|---|
| New Order | 0 | 0 | Y |
| Cancel (No Fill) | Equivalent 0.00005 SPC | 0.00001 SPC | Y |
| Order Expire (No Fill) | Equivalent 0.00005 SPC | 0.00001 SPC | Y |
| IOC (No Fill) | Equivalent 0.00025 SPC | 0.000005 SPC | Y |
| Transfer | N/A | 0.000075 SPC | N |
| crossTransferOut | N/A | 0.000075 SPC | N |
| Multi-send | N/A | 0.00006 SPC | N |
| Issue Asset | N/A | 10 SPC | |
| Mint Asset | N/A | 0.002 SPC | N |
| Transfer ownership | N/A | 0.002 SPC | N |
| Burn Asset | N/A | 0.002 SPC | N |
| Freeze/Unfreeze Asset | N/A | 0.001 SPC | N |
| Lock/unlock/relock Asset | N/A | 0.002 SPC | N |
| List Asset | N/A | 200 SPC | N |
| Submit Proposal | N/A | 1 SPC | N |
| Deposit | N/A | 0.000125 SPC | N |
| Enable Memo Check | N/A | 0.2 SPC | N |
| Disable Memo Check | N/A | 0.2 SPC | N |
| HTLT | N/A | 0.000075 SPC | N |
| depositHTLT | N/A | 0.000075 SPC | N |
| claimHTLT | N/A | 0.000075 SPC | N |
| refundHTLT | N/A | 0.000075 SPC | N |
| refundHTLT | N/A | 0.000075 SPC | N |
| TinyIssueFee | N/A | 0.4 SPC | N |
| MiniIssueFee | N/A | 0.6 SPC | N |
| SetTokenUri | N/A | 0.000075 SPC | N |
| List BEP8 Token | N/A | 1 SPC | N |
| Create A New Smart Chain Validator | N/A | 2 SPC | N |
| Edit Smart Chain Validator Information | N/A | 0.2 SPC | N |
| Delegate Smart Chain Validator | N/A | 0.0002 SPC | N |
| Redelegate Smart Chain Validator | N/A | 0.0006 SPC | N |
| Undelegate Smart Chain Validator | N/A | 0.0004 SPC | N |
| Unjail A Smart Chain Validator | N/A | 0.5 SPC | N |
| Submit Byzaitine Behavior Evidence of A Smart Chain Validator | N/A | 0.5 SPC | N |
| Submit Smart Chain Proposal | N/A | 1 SPC | N |
| Smart Chain Proposal Deposit | N/A | 0.00025 SPC | N |
| Smart Chain Proposal Vote | N/A | 0 SPC | N |
| Cross transfer out relayer reward | N/A | 0.0004 SPC | N |
Can I see orders/balances of others or can other people see my orders/balances?
Yes, anyone can see anyone's orders and balances if they know the corresponding addresses. SPC Chain is 100% transparent for transactions and balances.
Information provided through API and their usage
Is there any limit to using the API to send orders or check market data?
Yes, there are rate limits to ensure there is no waste or abuse of the network infrastructure.
Please check the API documentation.
What does Wallet and API cost to use?
No fee or commission at all (free to use).
What Market Data can I get?
The market data provided via Wallet and API are similar to SPC.com, including ticker data, order book,
trade and Kline. They can be seen in the Wallet and read from REST or WebSocket API.
Please check the API documentation for details.
What are the tick size and lot size? Are they fixed?
Tick size is the minimum unit to increase or decrease for the price (in quote asset) of an order,
while lot size is the minimum unit to increase or decrease for the quantity (in base asset) of an order.
They are not the same as on SPC.com. They can be queried from API or checked from Wallet UI.
Tick Size and lot size are not fixed. SPC Chain will automatically/periodically review the values to make sure proper order size and notional is applied.
Are there limits on notional value of an order?
The smallest order you can send for a trading pair is 1 lot size quantity at 1 tick size price. No other limits.
What is the decimal precision for prices and quantities on SPC Chain/DEX?
Amounts are represented as integers, and all coins have a fixed scale of 8.
This means that if a balance of 100000000 were to be exposed to a wallet integrator, this will represent a balance of 1 coin.
I forgot the private key for my address, how can I get it back?
Sorry, you cannot. Owner of the address takes full responsibility for the private key protection. SPC Chain and official wallets do not have your private key.
My private key got stolen by hackers, how can I recover my assets?
Sorry, you take full responsibility of your private key ownership and protection. SPC Chain and official wallets will not record, or transfer out your private key.
What is the Accelerated Node?
While users can submit transactions and most of the queries via normal, self-run full nodes.
Accelerated Node provides more secure and faster lines to access SPC Chain.
Accelerated Node is special infrastructure built around Validator to facilitate accelerated transaction
routing and provide richer, faster user interfaces. There are always several Accelerated Nodes running
at the same time around the world (owned by different organizations) and you are encouraged to choose
one of them to use, or allow your Wallet choose one randomly.
For rapid API access, you'd better stay with one Accelerated Node to get better performance.
How can I issue an asset?
Anyone can pay a fee and issue an asset as Token on SPC Chain, as long as they provide proper information for the fields below, and then execute the command through the command line or http interfaces.
- Name: a description string of less than 21 characters
- Symbol: an identifier string less than 9 characters, which must be composed of [0-9A-Z]
- Total Supply: a positive number less than or equal to 90 billions
- Mint-able: whether the token can increase Total Supply in later time or not
What is the consensus algorithm used on SPC Chain?
SPC Chain uses BFT and PoS (upcoming) based consensus mechanism to produce blocks among a series of qualified Validators. This is similar to the architectures of several existing popular blockchain platforms such as EOS and NEO. The process for setting up validators among different entities on SPC Chain is currently being defined. More details will be shared at a later date.
Can I run a full node for SPC Chain?
Yes, you can. A full node contains all the information and application logic for SPC Chain. It can receive and broadcast blocks and transactions with other full nodes and even validators. The only exception is it will not participate in the consensus if the full node is not a Validator.
Does SPC Chain support Smart Contracts?
No. This was an intentional design decision to improve the performance of the system and eliminate having to support unnecessary features.
If you have certain must-have feature-s, it might be added as a native implementation instead of using smart contract.
Feel free to talk to SPC community.
How can I transfer tokens, such as Bitcoin, from other block chains onto SPC Chain?
Right now, there are 2 ways to transfer tokens cross-chain:
- via interoperability among different chains. After the latest “Archimedes” upgrade, BEP3 was introduced and it defines native transactions to support Hash Timelock Contract (HSPC) on SPC Chain and it also to defines the infrastructure standard and procedure to use HSPC for inter-chain atomic swap to easily swap tokens on different chains. SPC Chain development community has finished implementing its solution for BEP3 with BEP2 and ERC20 tokens and decided to open-source all of the key components, including：
- smart-contract solution that supports Atomic Peg Swap (APS) for Ethereum. Please note that this solution is already audited by 3rd party.
- deputy process written in GoLang that handles swap activities
Any developer is welcome to test the solutions in testnet and then use them in mainnet.
- via SPC.com. SPC,the largest cryptocurrency exchange, has issued a number of crypto-pegged tokens on SPC Chain (BEP2 token format): BEP2 Bitcoin, BEP2 BCH,BEP2 XRP, BEP2 LTC. Pegged tokens such as BEP2 Bitcoin, are 100% backed by the native coin in reserve. The reserve addresses are published for anyone to audit. Read this blog to learn about the reserved address. Users are free to convert between native and BEP2 Bitcoin via deposit/withdrawal. This has a higher degree of ease-of-use for most traders. More swap channels will be provided on partner wallets soon.
Atomic swap and this centralized approach are not exclusive to other decentralized approaches, which can also be implemented in parallel. There are many cross-chain solutions being developed and we are very interested in them.
Please do NOT try to transfer anything on existing network to SPC Chain testnet, you may experience loss by doing so, because testnet doesn't run with real coins.
How is a trading pair created on SPC DEX?
The design philosophy of SPC DEX adheres to the idea that the most efficient and low cost way to perform trading and price-discovery is still to use single order book. This single order book is managed and replicated across all full nodes with the same, deterministic matching logic.
Simply allowing trading between two assets seems easy enough, however it is expensive for not only the network but also its users in long term (and liquidity costs can be much larger). In order to efficiently use the network, SPC Chain only list assets against SPC and other widely accepted market quote assets.
After an asset is issued, which costs a small fee, anyone can "propose" to all validators to list it against particular quote assets. Validators then vote to accept the proposal. A deposit is taken to prevent network abuse. Once the proposal is accepted, the owner of the base asset can list the trading pair.
For more information about this process please check the listing guide.
How would a third-party integrate with SPC Chain and SPC DEX?
A wallet provider may choose to only support the feature set of SPC Chain, which would just
cover wallets, addresses, balances and transfers.
To improve their implementation further, they could choose to integrate SPC DEX which would add trading (order placement and cancellation), historical order and trade views, charts, etc.