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Someone from the @TrustlinesFound community this week asked how UBI on #Trustlines would differ from @CirclesUBI. It’s funny because I’ve been asking the same question myself since discovering Trustlines existed. Actually, this is what led me to Trustlines in the first place.
I want to thoroughly address this. I’ve been a fan of both projects for some time. In fact, after feverishly googling “crypto ubi” a few years back, @CirclesUBI was one of the first projects that sent me down the blockchain hole 
I actually think the monetary theory behind Circles vs Trustlines is the most interesting part. Wrote a paper on this for a conference last year (already outdated, but PM if you want to read it). Basically I think mutual credit and UBI are complementary.
TLDR, #Trustlines and #CirclesUBI have different scope but are based on the exact same idea: #Rumplepay by @rfugger. (aka the "original Ripple" which predates blockchain, and itself was inspired by LETS systems)
Side note, notice that “original Ripple”/”Ripple classic”/ #Ripplepay has not long ago been renamed to #Rumplepay. So we officially have permission to stop being confused about the red herring @Ripple connection. (Also, what a cute name)
Even though #Trustlines & #CirclesUBI are based on the same concept, there are several differences in implementation. I’m highlighting here what I think are the most relevant differences so far:
1) #Trustlines is an agnostic tech stack on which you can do pretty much anything related to p2p credit, e.g. users can use mutual credit and co-create UBI within the same platform...
... #CirclesUBI was created for a specific vision (to distribute UBI), so even though it's based on the idea of p2p credit, you can't really use it for decentralized mutual credit (basically, there would be a cap on the amount of credit you can create).
2) On #Trustlines, users actively set credit limits for each new trustline. But #CirclesUBI, users can’t set credit limits (at least not from the web app). Instead, each connection is assigned a default credit limit (“trust limit”), expressed as a percentage of your balance...
...(50% currently). That means your credit limits are actually dynamic depending on your balance at any point in time. Theoretically you can launch a currency network on Trustlines with default or dynamic credit limits, but nobody did that yet.
3) On #Trustlines, you cannot hold someone’s debt without their permission—Every trustline must be signed by both parties...
...On #CirclesUBI, users can trust anyone, meaning you can hold anyone’s tokens (accept their money) even if they would rather not let you. Doing this would be like holding or buying the debt of strangers.
4) Any entity can create credit on #Trustlines: a person, business, community, organization, etc. But you’re supposed to be a *person* to mint currency on #CirclesUBI (org accounts aren't available yet).
5) If you want to close a trustline, you can ripple an outstanding debt to another trustline as long as there's a path. Don't think that’s an option if you cut off trust while holding someone's circles, though maybe it will be an added feature.
6) With #Trustlines you can participate simultaneously in as many different currency networks as you want, e.g., you can transact with Euros, USD, ETH, Hours, etc. using the same account...
...For #CirclesUBI, there's only one denomination: Circles! (Theoretically there can be many Circles hubs each with its own denomination, but you probably wouldn’t join more than one.) Interestingly, whoever pays my transaction fees seems to think that 1 CRC = 1 xDAI.
7) #CirclesUBI launched on xDAI. #Trustlines runs on Trustlines Blockchain. Also Circles uses a web app, @trustlines_app is a mobile app. But both projects are open-source, so you could theoretically copy either one and launch on whatever EVM blockchain you want with any UI.
8) On #Trustlines, information about credit relationships and balances are stored within the currency network smart contracts, and trustlines/balances are updated only when the user makes a transaction...
... #CirclesUBI uses the ERC-20 standard to mint personal tokens for each user on a regular basis.
9) On #Trustlines, anyone can set up a relay server and provide their own pathfinding service—The default relay server uses Dijkstra’s algorithm. #CirclesUBI uses a max flow algorithm. Theoretically you can set up your own (but need more details on how exactly @CirclesUBI)
Final note: Yes, you can implement something like Circles using Trustlines Protocol, though it would look a little different. UBI is one of the top use cases, though nobody has tried to do it yet https://docs.trustlines.network/docs/resources/wp_content/use_in_the_real_world.html#universal-basic-income
Congrats to the @CirclesUBI team on the launch, it’s very cool to see so many people excited to try UBI with an alt currency. Thanks @isthisanart_ for answering my questions, please correct me if I got anything wrong. Also thanks Jannik & Côme for helping puzzle through this! :)
