I was working in a start up until July, and I resigned to move to another continent. This start up is selling a specific product available in a SaaS Platform for retailers, no other company is doing the same thing right now as far as I know.

I found a new job in my new country since September for a consulting firm. When I first arrived my boss asked me to explain to him what I have done before so he can see which kind of clients could be interested in my profile.

Now he has told a prospect what I was doing previously, they want me to build the exact same product for them. I feel very uncomfortable, I don't want to copy my former company's ideas. I offered my boss (twice) to contact my former employer and build a partnership with them but my boss is clearly not interested.

I think this will be very costly to setup for just one client and not worth it anyway, and my boss asked me to send him costs/time for a proof of concept so I will send him big numbers in order to discourage them for starting the project.

What can I do if they still want to do the project anyway? Is it even legal?

Edit: To clarify the subject, I was the lead data scientist and know everything about the machine learning models that are used there. The product is completely based on these models, I am sure that these models are what my former company would like to protect the most. It is a very specific product that no other company sells.

Also my former contract says that every work I have done there belongs to the company in the country I used to live in AND abroad.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – user44108
    Nov 9, 2019 at 8:35
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    good question, great answers also. This is a great situation to re-think what you previously did and do it even better than what was done. The second time is always more robust than the first. And this further separates the solution you are about to write from the one you wrote. Nov 10, 2019 at 5:34
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    Was your employer aware of the system you built at the last job during the interview process? Was you having this knowledge part of the reason they hired you?
    – corsiKa
    Nov 10, 2019 at 17:46
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    Yes, use the opportunity to make it better than you did before! And, get your new employer to give you the freedom and resources to make it happen as such. Nov 10, 2019 at 20:40
  • @corsiKa no it never came up in the interviews.
    – anonymous1
    Nov 10, 2019 at 21:16

6 Answers 6


I'm not sure things are quite as cut-and-dried as you make them out. To the point where it's possible to proceed with a modified version of the project without ethical issues.

Let me explain with a few examples:

"I used to work for a company as an administrator/developer for an Inventory Management System. The new company I'm with want me to program an in-house IMS. Is it wrong to use my knowledge of IMS's to program our own version?"

No. Obviously not. I mean, it'd be one thing if you were copying their software, screen-for-screen... but merely writing a new IMS system? You're simply a developer that has deep experience in a very selective domain space. It'd be like someone with in-depth experience on Content Management Systems, or Logistics Routing Algorithms, or Computer Audio Effect Manipulation.

"I used to work for a company where I wrote an IMS. Now the new company I'm with wants me to write a different IMS. Is that wrong?"

No. You've got specific domain experience that you're leveraging - because unless you're copying actual code/specifics from your old project or duplicating things screen-for-screen - you're simply writing a new piece of software using domain experience. And just as importantly, you're not going to remember all the specific details about every facet of the first IMS. The two may be similar, but they certainly won't be the same software.

"I used to work for a company where I wrote an IMS. Now the new company heard about my previous IMS and wants me to write it again for them. Is that wrong?"

Which brings us to your situation. Except... you don't have to write the exact same IMS. Instead, the client wants an IMS. So sit with them, get requirements from them, work with them on screen layouts and such. Because at that point, you're not copying from your prior job, you're simply leveraging experience in a very specific domain space. And if the requirements/collaboration come from the new client, its very unlikely the new software will be a clone of the old.

If it helps, think of it this way: is it possible for your current employer to have another developer do it, if less efficiently/quickly? If so, then you're not talking about an ethical situation - you're talking about one where your experience is what's letting you tackle the project quicker than just a random dev.

*Note: This all assumes a few things you should make sure of first:

  • That you aren't violating any sort of non-compete clauses in either of your contracts.
  • That the idea itself isn't under any sort of legal protection like a patent.
  • That what I'm describing in terms of 'domain specific knowledge' is applicable to your situation (your question was awfully vague, so it's tough to know for sure whether this is good advice.)
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    @anonymous1 It is not required for anyone to actually sit down with a client. Your boss could simply be guessing at what a client wants, or the client could be the employer itself. You are employed by an employer and as long as you are using your knowledge and experience, and not copying previous code or company-specific knowledge, that is OK.
    – Brandin
    Nov 8, 2019 at 9:22
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    @anonymous1 You should point out to your boss that the previous program was highly tailored to the specific needs of your previous employer. If you write "exactly the same thing", then it might be useless for the new client! There will be features that they don't need/want, and features excluded from your previous IMS that the new client does want. To paraphrase: "One Size Fits None". Nov 8, 2019 at 13:57
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    This answer is potentially dangerous. It is treading in contract law territory while clearly dismissing any limitations imposed by the obligations of the contract save for a few disclaimers at the end. We can all reason about to support a conclusion we desire, but that doesn't make it good advice when it's likely a legal question. OP should see a lawyer.
    – vee_ess
    Nov 8, 2019 at 21:33
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    Good answer, but you repeatedly say something you should look into (with lawyers) before advising others. IP is not only protected from a 1:1 copy. That is ridiculous. It’d mean you could change your variable names or use arrays instead of strings; free from fault. That’s a lie. Technology is not “code”, it’s a process. The OP has every right to have concerns. Generally people must recuse themselves from projects that have this conflict. You can’t develop a cure for cancer and then go elsewhere and develop that same cure and think your hands are clean.
    – vol7ron
    Nov 10, 2019 at 13:10
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    As it was explained to me: "you can take what's in your head, but you can't take anything you've written down". So you're absolutely able to go work somewhere else and use your previous knowledge to make a near-identical product - you just can't use the source code, or anything non-public about the original to do so. To that end, if you could (reasonably, or likely, even if you didn't) make a copy of the source code, then the former employer could reasonably assume you used it as the basis for the new version you're making. This could be bad for you - so be careful. Nov 10, 2019 at 19:50

What can I do if they still want to do the project anyway?

Obviously you cannot reproduce your former company's product line for line.

But there's no reason that you cannot build a new product from scratch which has all the same features as the prior product. That's perfectly legal and happens all the time.

And now, with your experience, you can build it better.

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    There is a small caveat that just because something happens all the time doesn't mean it's legal, okay, or honestly even a good idea. Of course in this case it happens to be =)
    – corsiKa
    Nov 10, 2019 at 17:49
  • Re: " there's no reason [...] same features". I'm not familiar with the subject, but certain features are said to be implementable in essentially only one way, and that way is covered by a patent. Whether that's true, or litigation is feared, there's one reason.
    – Pablo H
    Nov 11, 2019 at 12:45

It sounds like you have identified that there are two questions for you to answer: Is it legal? Is it ethical?

With regards to it being legal, you need to consult a lawyer with your contract from your previous employer in hand.

Please don't mistake the comments or answers you've received as valid legal advice.

Trade secrets are a protected form of IP, and they don't require filings as they are protected through contracts. The notion of not copying "line for line" just means you're likely clear from copyright law, not contractual obligations. A lawyer in your part of the world, knowing the specifics, and having your contract can tell you.

Just by not "copying actual code/specifics from your old project" doesn't necessarily mean that you're solely "writing a new piece of software using domain experience." Sure, the bulk of what you produce will be from your domain specific knowledge. This doesn't mean that there aren't any discoveries, mechanisms, or other specific knowledge that are property of your previous employer won't seep in. In fact, with the curse of knowledge I'd be willing to bet there will be something stolen at the end. A lawyer in your part of the world, knowing the specifics, and having your contract can tell you.

A few more questions you might consider:

  • If your previous employer were to take legal action and win, who would be liable? remember that you, not your new employer, are under contractual obligation
  • If your previous employer were to take legal action and win, who would own the new product given that it would be found you didn't have the rights to it to begin with? lots of companies wouldn't want you on this project because of this type of risk
  • If this is what they are asking of you already, what are they going to ask of you next?
  • If you find there are concerns and feel obligated to do it anyways, are they going to be emboldened in the future?

Is it even legal?

It is definitely not ethical to use the business secrets of your previous company while working in the new one.

It is perfectly fine to use the general know-how: how to use the programming languages, which tools are better suited for the development (IDE's, debuggers...).

About being legal, you need to discuss with a lawyer, because the laws vary wildly from one area to another.

Also, read carefully again the contract(s), NDA(s)... you had with the previous employer. They might have statements exactly about this, which you do not want to break.

Sometimes, contracts limit the job choices of the employees, after they leave the company. E.g. not allowed to work in the same sector / business for a number of years after leaving the company.

What can I do if they still want to do the project anyway?

You have three choices:

  1. You agree, and you give them what they want.
  2. You do not agree. In this case, you should be prepared to find another job, they are likely to not take it lightly. Even if they will not fire you, your prospects mid- and long term would not be bright.
  3. You try to find a workaround - and this might the best thing you can do at the moment. You create a system with a similar functionality, but you make sure that the implementation is as different as possible, to avoid legal problems. The most important, do not use the know-how which is specific only to your previous company - create other architectures, other data flows... - you know better how to build it differently.

my boss asked me to send him costs/time for a proof of concept so I will send him big numbers in order to discourage them for starting the project

Well, that is a very good strategy, to discourage them by showing them the costs. You are quite lucky, to have the boss on your side.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – user44108
    Nov 11, 2019 at 7:23

Is your boss preparing to pay you some obscene amount of money?

I'm saying that because your old company is not just you. You had a boss, and probably other colleagues in your team doing other footwork to get the entire system setup.

Your boss is now asking you, a single person, to re-create the product of a company. Logically, that isn't going to happen.

If you took the most expensive part of a car, how much work is it to rebuild that car around this most expensive part (most likely the engine)? Something tells me your boss probably doesn't understand your previous job at all and somehow thinks you can replace an entire company. Of course, if he's really serious, then start planning out the staff you need (just replicate the entire company structure of your previous job) and see if he's still willing to support the project.

You honestly didn't expect to re-create the product on your own, did you? Even if you're the mythical 100x programmer, what about the legal requirements? You're in a different country. How do the privacy laws apply to you now? Should you patent/license/trademark the product? How do you even do that in this new country? etc, etc. You're not doing this on your own.

  • I know very well that I can’t do this by myself, I only know about the ML part. he wants to add colleagues to the project. Definitely he does not understand how that works (sales person with no technical background) and think this will be quick because I’ve done it before. I tried to make him understand that things will not be that easy but he just answers that we don’t have to rebuild everything but just a minimal viable product
    – anonymous1
    Nov 8, 2019 at 7:19
  • Keep talking to him. Let him know that you're working from memory. Ask the boss to do a day of work from "scratch" (no access to company resources; just his memory) and see how well he does. I bet he couldn't remember a single client's e-mail or phone number. How are you going to remember the functioning details of the product with no source code?
    – Nelson
    Nov 8, 2019 at 8:40
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    You are taking a much too literal reading of what OP's manager has asked and are now dismissing every reasonable interpretation because it doesn't stick to the overly literal interpretation you're using. OP's manager did not ask for a perfect-memory-no-help-allowed-one-man-company-project, and the suggestion that this is the only possibly thing the manager could've asked for is quite frankly ludicrous.
    – Flater
    Nov 8, 2019 at 11:33
  • @Flater Likewise consider that you might be taking too loose an interpretation!
    – vee_ess
    Nov 8, 2019 at 21:47
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    I didn't write this answer out of some imagined scenario of a manager having false expectation. I wrote this out of actual anecdotal experience of managers genuinely believing as such and myself foolishly thinking "they must be more reasonable". Take it with a grain of salt because I'm not psychic and don't know what the OP's manager is thinking, but I've personally been in this situation before. It is VERY shocking...
    – Nelson
    Nov 9, 2019 at 3:58

This can range from completely harmless to very shady.

  • Re-applying knowledge from your education/training resulting in the same product with well-known features and technologies (you are a "person skilled in the art") is no problem.

  • Obviously everything which required a collective work of a team and/or higher qualified persons (e.g. you were the programmer, and a data scientist e.g. PHD in math guided you and selected the machine learning approach to use) which your former employer sponsored is probably off-limits, for two reasons:

    • Intellectual property of your previous employer
    • You won't be able to maintain this (in the sense that you can react meaningfully to events)
  • Completely off-limits (and I heard of a person who has gone to jail for this) is everything where the knowledge of implementation itself may be a disadvantage for your former employer (trading algorithms in hedge funds).

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