Methods and systems for improved indexing of non-standardized, custom smart contracts. The improved indexer identifies custom landmarks (e.g., portions of bytecode indicative of custom smart contract transactions or particular functions in those transactions) that are indicative of transactions involving custom smart contracts (as well as the various attributes of those custom smart contracts). The indexer does this by first collecting bytecode for a subset of known transactions involving the custom smart contracts. The indexer then compares the bytecode of the custom smart contracts in the subset to identify the landmarks or probabilities that portions of the bytecode correspond to landmarks. Once these landmarks are identified (or a probability of the landmark is above a certain threshold), the indexer may designate these as known landmarks. The indexer may then compare the portion of the bytecode corresponding to the known landmark to raw bytecode. Upon detecting a match (or a probability of a match above a certain threshold), the indexer may identify the transaction and/or attributes of the transaction.