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Comment by andriosr | Hacker News Reader

Hi everyone,

I have been iterating a startup since the start of the year. And I'm using Clojure for everything I do.

The first product was a ledger service, but it ended up not fitting well as a managed service. We pivoted to a different idea and decided to open-source the ledger project.

It brings years of fintech experience, with the most common problems faced at scale for a ledger solved into the design.

I hope this will be helpful to some of the companies that are struggling with this kind of system.

Let me know if you have any questions :)

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Sequence has interesting applications for longer-term work I'm on, and/but I'm Baader-Meinhoffing [0] re more-immediate small-biz accounting ledger needs: I spent a good chunk of yesterday in gnu-cash and Frappe books [1] working to import/tag/script Chart of Accounts and transaction info from two banks while aiming to avoid (new-to-me) UI, code base, or Generally Accepted Accounting Principles rabbit holes.

Sequence is clearly an API and I ought stick with consumer packages @ immediate needs. I'll spin up the container to check it out in general; Please let me know if I'm mistaken / you recommend specifics it'd be helpful for me to check out and feed back on -

[0] - https://en.m.wikipedia.org/wiki/List_of_cognitive_biases#Fre... [1] - https://github.com/frappe/books

You're right. Sequence is a ledger API. These tools will give you higher abstractions on top of their internal ledgers. I think you are on the right track. If you want something extremely simple maybe the Ledger CLI [0] is worth looking at. Try to leverage these higher level abstractions. You don't need deep accounting understanding to import/tag/script a few transactions.

[0] https://www.ledger-cli.org/

Nice clean code! Thanks for open sourcing. I was a bit hoping to see how you were calculating amortization/interest charges in Clojure, but it appears to be only a pure ledger. Out of curiosity, were you using hashing to verify transaction chains? I saw code for MD5 hashes, but not where it was used.

Thanks! I have interesting ideas for amortization/interests, maybe they can get added at some point. Yes, the hashes are the ids used for Avoiding double-spending along with dynamodb conditional put. I’m on the phone now, will follow up with code once I get to the computer

Why did you go with a non-relational database?

Interesting question. No-SQL doesn't mean non-relational. DynamoDB is a relational database. It's up to you on how you design the table to accommodate your relations.

This is a great presentation about this: https://youtu.be/6yqfmXiZTlM?t=1447

DynamoDB is a key-value store. Key-value stores are not relational databases [1]

The link you posted is a really good resource for someone who wants to start using DynamoDB though.

[1] - https://aws.amazon.com/nosql/key-value/

You're right. DynamoDB is not a relational database. But data in DynamoDB can be relational just as in a regular relational database: https://docs.aws.amazon.com/amazondynamodb/latest/developerg...

That's really stretching the definition of a 'relational database'.

You can create relationships on flat text files. It doesn't mean that you have a relational database now.

Many have fallen for that marketing video stunt and later regret it.

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