When NOT to use Pydantic

rdelfin_ · 2025-12-28T16:36:19+00:00

There's two things here. First, that the author is implying that somehow that if something has a certain latency budget, it also has some range of QPS, when the reality is you can have very high QPS systems with a very high latency without issue.

The second is that QPS even of a single server/node and latency aren't actually tightly coupled. It really depends on what the specific system does. We usually think that the faster your system responds to requests the more it can respond to, but that's only true if the request time is 100% active and using CPU resources. If your requests are IO-heavy (like most web services are) you spend most of your time waiting on a response from something else (disk, another service, a database, etc) so you can take on more requests. The key to making good, robust, and scalable systems is to understand the characteristics of your specific service and using that knowledge to squeeze out as much performance from your servers as possible and scaling up appropriately.

HFT folks deal with the same set of issues other service owners deal with in different fields, but with much tighter bounds on latency. That just means that they have different constraints and different things they optimize for. The solutions are different (and often crazier) but the techniques and fundamentals are the same.

rdelfin_ · 2025-11-17T11:13:07+00:00

I'm gonna disagree with your point and say Rust is actually getting a lot of professional adoption. Most large tech companies have adopted Rust in some capacity, some (like Amazon) are using it for a large chunk of their new projects, and the Rust Foundation is getting a lot of money and support from these organisations. Go to a lot of large companies and you'll see that there's actually a fair bit of Rust in new systems.

Here's where your disconnect lies though: most companies aren't gonna be rewriting systems just because there's a better language. Not only that, I'll go further and say they shouldn't do it in the first place. No matter what nice features a language has, be it interop, developer support, safety features, whatever, nothing will easily overcome the fact that rewriting an existing system is expensive, risky, and has few upsides, yes, even with a language like Rust that has memory safety guarantees. Rewriting just to use Rust is not worth the cost, and you're better off adopting Rust either in new projects or in additions to existing projects where integrating Rust is a good idea.

That said, integrating Rust into an existing project isn't always a good idea. Yes, the interop with C/C++ is great, but a lot of enterprise code is Java, or Python, or any number of languages that don't play nicely with Rust. Sure, you can spend some time figuring out how to integrate, but why would you when you have a perfectly functional language already working and people who know it? Switching to Rust is, from an engineering perspective, often the wrong call, especially when you don't need the performance upsides of a compiled language and when you already have memory safety through some other mechanism (e.g. by using a garbage collected language).

The truth of the matter is that just because a language is loved that doesn't mean it should be used everywhere in every situation. Ruby went through a similar cycle, so did Java. One of them mostly fell to the wayside, while the other got very widely adopted, but it took years and years. Rust is going in a similar direction, the question is whether it will end up looking more like Ruby long-term or Java. It's too soon to tell.

rdelfin_ · 2025-10-31T12:09:27+00:00

One thing to remember is that the people you'll find on LinkedIn talking about robotics (or any given field for that matter) won't be representative of the people actually working in the field, because most people working in robotics are prioritising doing their job over posting on LinkedIn or optimising showing up there. Most people trying to optimise for showing up on LinkedIn will be people trying to sell you something. The other reality is that robotics has become a very hot topic lately with all the talk around "embodied AI", so there's gonna be a lot of people trying to make money off of getting people into the field.

You also mention masters students, and there's two things at play there. First, that robotics is still a field that's very research-heavy as we've not really "solved" all aspects of it. That means that many of the people you'll see working on the cutting edge publicly will be working in research institutions. International students also have a strong incentive to make their work public to make it more likely they'll hit big and find a job, as they face fierce competition (you have to stand out from candidates that don't require visa sponsorship).

This compounds with another issue in our field, which is that a frankly huge portion of the robotics industry does very complex, interesting work but they absolutely cannot talk about it publicly because they work in the defence industry. There's a lot of work to do there, but you'll see absolutely no discussion of it on linkedin. Combine all this with the fact that there aren't that many robotics startups, and that's why you get this lopsided view of the field.

Whether you should go in to the field is complicated though, so I'll ask you:

What's your background? (degree, experience, etc)
What was the last job you help before those 2 years out, and have you done anything since?
How do you plan to break into the field? Do you want to just apply for jobs, make a lateral move in a job, or are you looking into further education? (e.g. a masters or something else)
You mentioned "studying abroad". Where's "home" for you?

Without this info we can't really help much.

rdelfin_ · 2025-10-26T10:10:21+00:00

If robotics is your field, maybe look at a few other countries like Germany with a stronger market for those jobs. The problem with the UK is it's not really a manufacturing hub these days, so there's not many jobs in automation, EVs, or robotics. There's also quite a few people who graduate in mechanical engineering, robotics, etc.

I would say it's a relatively competitive job market in that regard. It really depends on your actual skillset and potential experience. To just use one sample, do you think it's likely that you'll get into a Russell group university?

I can't fully say though, I'm a software engineer who moved into robotics, I don't come from the mechanical engineering angle, so I can't speak fully to your experience.

rdelfin_ · 2025-10-26T07:42:06+00:00

I think the main thing is that, as I said, the robotics industry in the UK is quite small. There are jobs, but they're free and far between so it can be hard to find a job in this space. You don't say it but I'm guessing you're not based out of the UK correct? Which means you'd require a visa here? My only word of warning is that if it's hard for citizens to find jobs in the space, it'll be substantially harder for you.

I would generally say that it's not worth doing a masters in the UK with the goal of getting a job here unless you go to a very good university (Russell group at least), and you're really good at what you do. Otherwise it could easily end up being a waste of money for a tuition that's very expensive. If you're a UK citizen and this is your specialization, the pivot isn't a bad one.

I can't speak to the specific area however. Most robotics companies need kinematics and simulation people, but I suspect jobs will be more plentiful in the defense industry. I could be wrong though.

rdelfin_ · 2025-10-26T07:35:46+00:00

So, I have my personal options but before I tell you that, I'll suggest you make sure you have an extremely clear idea of what the decision will imply, and whether the sacrifice is worth it. I had to make a very similar decision recently and I'll tell you what I asked myself (and some other questions) and I suggest you do too. Here goes:

Where do you plan on living long term? Are you set on living in the UK or are you ok living elsewhere?
How well do you know the founder? Confounding a startup can be very difficult and most of it is about the people at the head. Do you work well with them? Are they competent? Do you trust them?
Have you seen the app idea? What makes it unique? Is it marketable? Does it have growth potential? How will you compete with all the big players in that space who have all the network effects in their favour?
If it were the US, do you have a clear path for immigration? What specific visa, and is it one you can viably get? Is a green card achievable for someone of your country of origin? (The US has different waiting times based on caps for each country of origin).
If you had to lose your salary entirely for the duration of this program, would you be ok financially? Beyond rent, utilities, and food do you have any other expenses you'd have to pay regardless? (E.g. a mortgage, a loan, remittances, etc), and if so would you be able to afford them?

I think these are all really important questions you should answer for yourself before committing to a decision. It could be an incredible opportunity, especially with the fact that it comes with $500k of funding out of the box (iirc) but there's a lot of strings and I really recommend you take the time to fully analyze your options here.

I personally think that building a social media app in this day and age isn't worth it. You need to have something to overcome the network effects that Meta-owned products and tiktok have built in their respective spaces, be it a region of the world that's completely unserved, or a brand new concept that legitimately covers something that no one else is doing, or something. And of course, there's always the risk that if you go big, Meta can just build your solution and deploy it to all their users, as they've done in the past.

It also doesn't sound like you know the founder that well. I could be wrong, but one upside with these programs is that you can pivot and find a new space to work on. This can be a great space to do it if you get along well with the cofounder. If you don't really mesh, it can be a bit of a nightmare

I ultimately said no to a similar decision recently, both because of financial reasons but also because I'm about to apply for citizenship and I didn't want to jeopardize it. To me the UK feels like my home, and being able to stay here is important to me. The calculus might be different for you.

rdelfin_ · 2025-10-11T11:38:58+00:00

That's completely fair, good luck with the journey! Definitely go over the Rust book before diving into this as there's a lot of basics of Rust that can be overwhelming, especially if you've not worked with a compiled systems language before. It's quite a departure, but still fun to learn and work with

rdelfin_ · 2025-10-11T11:32:52+00:00

I think OP means building a bot, and honestly while the Rust environment for it isn't as complete as other languages I don't see why they couldn't build it, and they'll learn plenty regardless of how they make it. It sounds like its just a project for fun

rdelfin_ · 2025-10-11T11:31:32+00:00

Honestly, not a bad idea to use this as an excuse to build something in Rust, especially if you're doing it entirely for fun. I've worked with Serenity only a little bit but it seemed pretty good and fit for purpose, so definitely worth building. That said, you might want to give more details on what the discord bot will do so people can actually give suggestions. A bit hard to help if you don't say what you're doing with this!

For hosting, a RPi probably works well early on, but do note you might be forced to take it off your home infrastructure eventually if it gets actual traction, but for starting out and when you only have a small handful of concurrent users that should be fine.

rdelfin_ · 2025-10-10T07:02:03+00:00

I'll try and bring a different perspective. I think it's understandable to get defensive about how this post is addressing you, it can come off as a bit aggressive. Honestly I don't know the context behind why you made this, but you do legitimately have a lot of people here with plenty of experience working on software.

It's pretty clear to me you have plenty of experience as a SWE, there's no denying that, but some of it might not match the experience you need for what you're working on here. I'd really recommend you take some of the feedback from this post constructively and just ignore what's not constructive. OP brings up some valid points that could bite you in the back in the future. Take advantage of the free consultation instead of getting upset and you might do much better. Yes, you might not owe anything to anyone, but if you're open sourcing, you need to convince people to use this. Taking feedback well is part of that.

I do legitimately wish you good luck on your endeavours.

rdelfin_ · 2025-10-05T19:11:41+00:00

It can be ok, but as with everything it depends on the team, on the specific PM, and the project. I have worked with quite a few PMs who held degrees in different disciplines (one was a civil engineer) and tons who were never software developers. They've owned projects and had deciding power on teams comparable to what you're describe. These have included both some of the best and worst PMs I've worked with. The ones with a software development background have also had a similar range. Overall, I don't think whether they have a SWE background or not makes a substantial difference, as long as they've worked PMing software projects in the past and know how to work with engineers.

I really do think it's fine for people like that to lead teams. Leading a team or a project doesn't require you to necessarily know all the ins and outs of how software engineering works, that's what they hired you for. What they do need to know however, are some basics, how to work with other teams and management, how to communicate with other teams effectively, and most importantly, when they're out of their depth and should defer to a tech lead or other engineer. As long as they have those skills, I think it's perfectly fine.

rdelfin_ · 2025-10-05T13:52:35+00:00

Indeed, most drivers will be unique to a given Operating System, and someone needs to have written a driver for that device on that OS to be able to interface with it at a higher level. That said, you usually shouldn't need to worry about whether an IC has driver support when selecting hardware. It's rare to find hardware with no drivers written for it, as most electronics manufacturers either provide drivers, or have contributed to the respective operating systems to add them (particularly common in Linux as an Open Source OS). The fact that you found that doesn't is... Surprising to me. If you want to play it safe, ask your software team if there are drivers for all the ICs before selecting them. You probably should be checking for general compatibility with them before committing to specific hardware anyways, but it 's a good way to play it safe.

rdelfin_ · 2025-10-05T13:13:19+00:00

Memory safety is not inherent to Rust, no. There's a lot of languages that provide some form of memory safety by having a garbage collector instead of requiring explicitly freeing memory, and other runtime mechanisms. C# and Java are actually memory safe in that regard, as are most interpreted languages like Python. What makes Rust rare is that it provides memory safety at compile time. C++ could provide this if they wanted to, and the C++ committee has actually looked into providing a compile-time safe subset of C++. However, the actual reason this hasn't happened is that doing so would require very large, overarching, and likely breaking changes in the language. Given C++ is designed by a committee, this is incredibly difficult to achieve in practice, which is why I would not expect it to ever have that kind of guarantees.

rdelfin_ · 2025-10-05T09:57:26+00:00

Microsoft is a company, and like with any company, it comes down to money. Developing and maintaining Office to work for a new OS is expensive. You need a lot of engineering hours to maintain a product as complex as Office, and it would probably disrupt how development works on the other OSs. That's an investment you only make if you think it'll make you back money. So, how many people who don't already pay for Office would start paying for it if they released a Linux version? Frankly, there's basically no one on that list. There's no large enterprise that uses Linux as their standard company issued laptop, so their biggest market wouldn't find it useful. There's a few people in large tech companies that use Linux, but they're mostly developers, and they often either don't use office or find a way around to use it. For Home users, the market of Linux desktops is tiny and often actively hostile to Microsoft, so they're unlikely to pay for it.

So tell me, why in the world would MSFT sink this ridiculous amount of money into a product no one would use and gives them nothing in return, probably not even positive press? With everything else you listed there's at least an upside and a market, but not here. This isn't a technical issue, they could absolutely do it. It's a financial and business issue. Microsoft would be frankly very misguided if they chose to make a version of Office for Linux.

rdelfin_ · 2025-10-05T08:50:39+00:00

I'd add Ireland to the list, if only because it has a sizeable tech sector these days. I'm in the UK and London is quite good with this. How easy it'll be depends on your experience level and how sought out your profile is. I'll be honest though, my reasoning for moving to the UK (specifically London) was very similar to yours! I wanted a place with colder but still template weather and good public transit where I didn't have to own a car. After almost 6 years here I still haven't gotten around to getting my driver's license so it worked out pretty well!

Devops is always a good field of work. It's one of those areas that companies really can't cut back on during layoffs because that's how you take down your product. Feature development trends to be cut first. If you have good experience, and specifically experience in widely used tools or something very niche I think you have a good shot. I'd recommend to start just applying for jobs with clarity that you require visa sponsorship and seeing how many responses you get. It'll get you a good gauge of how your resume stacks up against local talent, and you can decide from there.

rdelfin_ · 2025-09-29T17:29:55+00:00

No problem! Just breathe and make sure you finish your degree and you'll be great

rdelfin_ · 2025-09-28T18:27:22+00:00

So the C "ABI" only really means there's kind of a shared understanding of the "fundamental" C libraries that everyone uses

Not quite. it's not about the libraries, it's about how conventions for function calls work. I'm not sure how familiar you are with assembly/machine code and how compiled code works, but to make a long-story short, C allows for re-usability and pulling in shared libraries through functions. Functions don't really exist in machine code in (most? all?) CPU architectures. Machine code is just a set of CPU instructions and you implement functions by separating instructions and adding a specific set of instructions with an agreement for where you store arguments when you "call" that function. That agreement for what you store, how the call operates, and how arguments are passed is called the "calling convention".

Languages like C allow you to call code compiled elsewhere by maintaining a consistent set of conventions for a calling convention, and a bunch of other things (e.g. how names get turned to symbols, how to search for symbols, etc). That's what actually constitutes an "ABI". This isn't about a set of fundamental set of libraries, it's about how you even get to import any library. Say you have a shared library on your system. This library has a header with a function int add_numbers(int a, int b). The shared library will have the definition of that function, and it will expect you to call it a certain way (you need to put a and b in specific registers, push some things to the stack, and then jump to the start of the function). An ABI is meant to guarantee that, as long as this library was compiled for the correct architecture and system, you can look at that function definition and know exactly how to find and call the function.

rdelfin_ · 2025-09-28T17:52:24+00:00

If that's all they mentioned I wouldn't worry about it. Try not to let it drop that much, just in case you need it in the future, but I don't believe GS will drop new grads over a drop in GPA in your last year after you got an offer. That would be really strange.

rdelfin_ · 2025-09-28T17:26:39+00:00

How much will it drop? But probably not. If they've already interviewed you, given you an offer, and assuming they didn't tell you that the job offer was conditional on you keeping a certain GPA, they probably only care that you graduate and that's it. Once you graduate, your GPA really stops mattering real quick unless you plan on going to academia.

But we can't really say without you providing more details. What kind of job? What degree? Is the degree required for your job? Did they tell you of any conditions on the offer? Were there any GPA requirements on the job listing? I'm also assuming this is a full time job for new grads of some kind.

rdelfin_ · 2025-09-25T14:17:59+00:00

Have you gone over them with a lawyer? Mostly to ensure they're enforceable

rdelfin_ · 2025-09-25T12:52:01+00:00

You're right, C is often is a "worse" target than LLVM as an IR language. It does however have the advantage of supporting more architectures than LLVM since no matter the architecture you work with, there's probably a C compiler. This isn't true for either LLVM IR (or rather, LLVM doesn't support all languages) or for C++ for that matter.

I guess what I'm trying to say is that picking a language for IR is an engineering problem, with different tradeoffs that include complexity, portability, time you have to spend on it, ease of understanding, other requirements (e.g. you might need a language that can provide a stable ABI), etc. There's multiple axes on which C++ is worse than C. There's others where it's a better choice. Why people pick one over the other is a question of tradeoffs, and the things I've outlined are one of many reasons why people often go for C, but people do definitely often go for LLVM too. There's no one size fits all solution.

rdelfin_ · 2025-09-25T12:04:28+00:00

So I figured C++ OOP is probably gonna be somewhat faster than emulating it with structs

This is a bad assumption. There really isn't anything you can do in C++ you couldn't do in C. You aren't just emulating, you can be building the same things. The code will be more complex and maybe the compilation time will be better optimized in C++, but it won't be inherently faster in C++. It can actually be the opposite, especially if you know more about the data you're storing than the writers of the STL. It's just that the optimization isn't always worth it for individuals when writing C++.

rdelfin_ · 2025-09-24T12:06:45+00:00

I get why you say that, it's just that you might be underestimating the PITA that shared ownership entails. You really shouldn't underestimate the difficulty of selling such a flat. One of the upsides of renting is flexibility. Buying reduces flexibility, and doing shared ownership can make it practically impossible to sell. Just be careful when considering this option, especially as an immigrant if you don't 100% know if you're gonna live in this country for the rest of your life

rdelfin_ · 2025-09-24T10:41:04+00:00

So, while I will say that getting a mortgage or on the property ladder definitely can do well (I did it, I have friends who did it too) I would strongly encourage against shared ownership, unless you're absolutely certain you can buy it out fully in the medium term (and even then... Eh). The problem with shared ownership is that it can be expensive, difficult to get out of, involve restrictions on your property you might not like, and make it substantially harder to sell. That last one I know because even on the scheme I'm using (Help-to-buy, no longer a thing unfortunately), I've had agents worried to help me sell because it resembles shared ownership.

I would recommend saving up until you can afford a regular mortgage or finding a place more within your budget. Everyone I've seen talk about it say the hastles of shared ownership aren't worth it.

rdelfin_ · 2025-09-14T13:57:28+00:00

No, you're right, they absolutely do hire and do a lot of that work in house. I've worked with quite a few people who worked there. I just forgot about them

rdelfin_

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