Memo Length Reduction
Reducing Memo Size
Given the complexity of memos, they can become very long, beyond the limits of chains like Bitcoin. Various methods have been developed to significantly shorten memo length.
Example:

SWAP:ETH.ETH:0xe6a30f4f3bad978910e2cbb4d97581f5b5a0ade0:1612345678:thor1el4ufmhll3yw7zxzszvfakrk66j7fx0tvcslym:10
can be reduced to
=:e:dx:161e6:t:10

SWAP:ETH.USDT0xdac17f958d2ee523a2206206994597c13d831ec7:0xe6a30f4f3bad978910e2cbb4d97581f5b5a0ade0:10012345678:thor1el4ufmhll3yw7zxzszvfakrk66j7fx0tvcslym:10
can be reduced to
=:ETH.USDT:dx:100e7:t:10
The examples below use the following features to reduce memo length:
Shortened Asset Names
Native asset names can be shortened to reduce the length of the memo. The exact list is here.
Shorten Asset  Asset Notation 

r  THOR.RUNE 
a  AVAX.AVAX 
b  BTC.BTC 
c  BCH.BCH 
e  ETH.ETH 
g  GAIA.ATOM 
n  BNB.BNB 
s  BSC.BNB 
d  DOGE.DOGE 
e  ETH.ETH 
l  LTC.LTC 
Example Swaps:
=:ETH.ETH:0x388C818CA8B9251b393131C08a736A67ccB19297
is reduced to=:e:0x388C818CA8B9251b393131C08a736A67ccB19297,
Swap for Ether.=:r:thor1el4ufmhll3yw7zxzszvfakrk66j7fx0tvcslym
 Swap to RUNE.
Asset Abbreviations
Assets can be abbreviated using fuzzy logic. The following will all be matched appropriately. If there are conflicts, then the deepest pool is matched to prevent attacks.
Notation 

ETH.USDT 
ETH.USDTec7 
ETH.USDT6994597c13d831ec7 
ETH.USDT0xdac17f958d2ee523a2206206994597c13d831ec7 
THORNames
THORNames allows a custom name to be assigned to an address, like an alias, so the address does not need to be specified.
Example:
thor1nt2d4kmj0xd6xxm3m82tac3d20y05dm0vv7ur3
can be specified astr
.
See the THORName Creation Guide to create your own. This is used greatly to specify the affiliate address.
Shortened Functions
Memos contain functions such as Swap or Add, which describe the user's intent and are sent along with specific parameters. Functions can be reduced in the following way:
Function  Abbreviated  Recommended 

Swap  s  = 
Add / Deposit  +  
Withdraw  wd   
Loan Open  Loan+  $+ 
Loan Close  Loan  $ 
THORName  name, n  ~ 
Limit Order  Limitto  lo 
Example:
SWAP:e:0x388C818CA8B9251b393131C08a736A67ccB19297
is reduced to =:e:0x388C818CA8B9251b393131C08a736A67ccB19297
Scientific Notation
In THORChain memos and the state machine, asset amounts are expressed as Base in 1e8 format requiring many digits to express an amount. E.g. 0.01 BTC is expressed as 1000000
and 5 Ether is expressed as 500000000
.
To help save space in memos, scientific notation can shorten memos by specifying both significant digits and the amount of trailing zeros. Note that using scientific notation in memos always leads to a loss of precision, so ensure enough significant digits are used to express the amount properly. For example, using 161e6
to represent 1612345678
results in a loss of precision.
Examples:
 In memo:
1e8
> THORChain reads:100000000
 In memo:
51e7
> THORChain reads:510000000
Full Memo Example:

SWAP:ETH.ETH:0x388C818CA8B9251b393131C08a736A67ccB19297:1612341234:thor19emplkuphjk2y9gkkv06m8vcstc0ufn4pevv5u:10
is reduced to
=:e:0x388C818CA8B9251b393131C08a736A67ccB19297:161e6:t:10