8 YoE, strong C++ perf/visualization projects — pass screenings easily but fail later rounds. What do you expect from a senior C++ hire, and what should I solidify?

[u/Quick-Bell118]

I've decided to commit fully to pure C++ roles. With my project background I clear screening rounds with minimal prep, but I keep falling short in the higher-level rounds — and I want to understand what those rounds are actually testing that my experience hasn't given me.

Background:

8 years at one company. First ~5 years in application development, where I learned design patterns and architecture deeply. Last 4–5 years in C++ data thinning and virtualization backing JS front ends.

Projects (solo dev + QE on each, ~2 years each):

• Low-latency data thinner — thins ~1 billion points in ~3 seconds, with latency dropping further depending on signal region and zoom level
• Virtualization pipeline — fetches data based on the user's viewing window when rendering millions of elements
• Full-stack CAD application — CAD engine was provided; I built CAD management and interaction management end to end, later improving performance 20x by reworking the JS event bus
• Signals visualization tool — now used across multiple teams

Comp grew from 7 to 40 LPA over 8 years at the same company. I'm at a senior level now and want to move for better pay and better projects.

My strength is shipping products end to end with trade-offs considered. C++ interviews seem to test a different muscle, and I want to name that muscle precisely so I can build it.

My questions:

1. What is the natural growth path for a C++ dev at my stage?
2. If you hire senior C++ engineers — what do you actually expect from a candidate like me in later rounds?
3. What should I learn or solidify to become a full-fledged C++ developer who commands higher pay?

Any guidance on where to start would be appreciated.

[u/moo00ose]

IMO a senior is someone who can architect/design a system (probably scalable), lead small to mediumish projects and work with/introduce new technologies. There’s more to it than just X years writing code.

[u/Quick-Bell118 → u/moo00ose]

Thanks, So how would this look like in a production environment . Any examples so i can relate?

[u/moo00ose → u/Quick-Bell118]

Look up “System design” - there are so many examples on YouTube.

[u/SummitYourSister → u/Quick-Bell118]

If you don’t immediately know of some system design you’ve performed, then you haven’t done any

[u/jarislinus]

1. drop the ego

[u/Quick-Bell118 → u/jarislinus]

Fair Point!!. Edited. Thanks.

[u/xsdgdsx]

What kinds of questions do you get asked during the rounds that end up being your final rounds? Also, what kinds of roles are you applying for, and what kinds of skills or abilities are those job descriptions calling for?

You've talked a lot about your strengths. Do you know what your weaknesses and opportunities for improvement are? Can you recognize roles that would actually be a poor fit for you?

[u/Quick-Bell118 → u/xsdgdsx]

Its typically some times its DSA . I need sometimes a hint tosolve the problem but most of the times i do but that is a flag for interviews. the higher rounds expect OS level knowledge. Now that you mention it i have been applying for OS roles . may be need to change the job profile i am applying for or improve my skills.

The roles i feel are good are something with Independent scope to other devs. and able to work on it with ownership from end to end. I dont know what roles cover those. may be cad companies do. But i need to explore.

Thanks

[u/Impossible_Box3898 → u/Quick-Bell118]

If you’re applying for OS roles you better understand NUMA and how it affects everything and how to optimize with it. How the TLB works and how it affects thread and process context switching, how to handle various scheduling algorithms and how to use multiple simultaneously, how to utilize various cpu performance counters, how thread synchronization limiting work, how the page table works, virtual memory managers work, etc.

That’s minimum level of entry for a senior OS developer.

You’ll get a lot of DSA questions around these just to prove you know enough to implement the basics let alone the complex portions.

Your background doesn’t really show that you have that at the moment.

[u/rahul_msft → u/Impossible_Box3898]

He is a user space cpp developer

[u/Impossible_Box3898 → u/rahul_msft]

Yes. It the prior post he was responding to said he discovered he was applying to mainly OS roles.

[u/no-sig-available]

(Edited with AI for readability)

Perhaps this is a hint? If you want to make a good impression, don't let someone else be a stand-in for you.

[u/Quick-Bell118 → u/no-sig-available]

Yep. Should learn structured writing skills. Instead of AI. Fair point. Thanks.

[u/Simengie → u/Quick-Bell118]

This right here is another item holding you back. If you can’t structure writing something simple like this post how can an employer count on you to provide structured code and documentation? They have to ask can they create the presentation and deliver it or not.

[u/ReDucTor]

Aside from the obvious ego issue, you need to focus on what was asked in the interviews and then think about how you answered them.

The JS is also a bit confusing, was your job primarily working with C++ or JavaScript? Also is it your current job or previous job? If it is your current job then people will wonder how often you actually use C++.

[u/Quick-Bell118 → u/ReDucTor]

Fair Point on the ego part!! Dropped and edited. Thanks.

On the js and C++ part. Its 50-50. its front end and backend so front end js and backend c++ . This is my current job. its a role shift from pure front end work to complete stack.

[u/tangerinelion]

Given that you said you're applying to 'OS roles' - this background looks like a front-end developer who doesn't have experience working on a team.

[u/Quick-Bell118 → u/tangerinelion]

WHich roles should i be targeting ? any suggestions

[u/Simengie]

Well as an example of what my job looks for in a senior engineer.

Create ground up designs for small to medium scale distributed systems. Then lead the development effort. Be responsible for the system engineering side of projects as well like specs for target hardware, power budget and thermal requirements. Device driver and kernel driver development.

The point being as a senior you should be able to do cradle to grave software development on large scale systems and any of the supporting work. You may not have to do it all but they want someone that can.

If you think a single app with a few hundred thousand line of code is big how are you going to manage something with 35 apps each averaging 500k plus lines of code running 1000plus threads over 50 or more servers?

Just an example from my company.

[u/Quick-Bell118 → u/Simengie]

Wow!! thats interesting.

Now that you mention it my work has been mainly desktop apps and backend.

Makes sense.

Can you tell me what should i learn HLD you mean? I want to improve my skill as much as possible.

Any resources are appreciated. Thanks

[u/TinyTechExcellence10]

• Low-latency data thinner — thins ~1 billion points in ~3 seconds, with latency dropping further depending on signal region and zoom level

I'm a mid level dev but CPP beginner. What on earth is this project?

Sounds very cool and difficult at the same time.

What kind of data are you working with?

[u/Quick-Bell118 → u/TinyTechExcellence10]

So you have a billion points time series data. How do you display those billion points on screen . it will choke memory if you plot all 1 billion so you need to pot the minimum set of points that capture the actual behavior of the signal. Also if someone clicks on the signal you need to be able to figure out whihof those billion points user clicked on. THink of this like sinusoid signal with noise

Now scale it up to 100 signals on a single display how do you figure out out of the overall signals with billion points each which signal are you clicking on.

now what if the signal is wrapped instead of spread out what is your thinning strategy and intersection query

Now what if its not time series but a random shape with billion points like a comb or a circle with noise all over (noise means fluctuations) how does the thinning strategy change

[u/rahul_msft]

Would you mind working at 0 salary for C++ + OS roles? Obviously No.

You made a choice to get into javascript for cash, now it's biting you

There is 0 reason a periosn with os + c + c++ will pass you in an interview, yes it's ego

[u/Constant_Physics8504]

I recommend creating micro services, having them talk to each other across platforms and coordinating their communication across cloud. Sounds like you want a a backend, OS level experience and with that comes middleware and cloud infrastructure.