Otdfbt

I think this diagram from a Quora answer covers it nicely:

• Contraption:

A machine or device that appears strange or unnecessarily complicated, and often badly made or unsafe.

A few options:

makeshift

noun

a usually crude and temporary expedient

source: Merriam-Webster dictionary

jury-rig

transitive verb

to erect, construct, or arrange in a makeshift fashion

source: Merriam-Webster dictionary

jerry-built

adjective

1 : built cheaply and unsubstantially

2 : carelessly or hastily put together

source: Merriam-Webster dictionary

jerry-rigged

adjective

organized or constructed in a crude or improvised manner

source: Merriam-Webster dictionary

They are closely related in meaning; Merriam Webster disambiguates: 'Jerry-built' vs. 'Jury-rigged' vs. 'Jerry-rigged'. jury-rigged is makeshift, but not necessarily of low quality. jerry-built is low quality, but not necessarily makeshift (and not in common use, at least not in AmE). jerry-rigged combines the two together to imply both.

Depending on context, there may also be appropriate jargon, such as hack in programming (an improvised work-around to a problem, may be sloppy), or homeowner special in real estate (a modification made to a home, usually poorly implemented, that is in violation of good sense, good taste, and/or building codes).

Specifically related to software, I would say:

hack

A hack is often used by programmers in English (in the US at least) to describe code that may function as desired, but is not up to standards and may have expected or unexpected negative consequences.

A "hack" implies something that was quick, dirty, and technically is functional, but should be corrected and done properly as soon as possible. Hacks are often intended as short term solutions but have a nasty habit of living on far longer than planned.

Sources

• terminology - What is a hack? - Software Engineering Stack Exchange


• 25.3. Hack and Workaround Management 101 - Web Design in a Nutshell, 3rd Edition [Book]


• A Dirty Hack – Joseph Gefroh – Medium


• Dirty Hacks Are OK - Bozho's tech blog

In modern computing terminology, a "kludge" (or often a "hack") is a solution to a problem, the performance of a task, or a fix to a system that is inefficient, inelegant ("hacky"), or even unfathomable, but which nevertheless (more or less) works.

> Kludge - Wikipedia

I suggest BODGE

bodge

VERB

[WITH OBJECT]

British informal

Make or repair (something)
badly or clumsily.

‘the door was bodged together from old planks’

https://en.oxforddictionaries.com/definition/bodge

The British English for this is 'lash-up'. This implies that the solution is improvised on the spot with whatever is available, but doesn't necessarily mean that it is a bad or inadequate solution.

What comes immediately to my mind is...

half-assed

From Merriam-Webster: "lacking significance, adequacy, or completeness"

From Dictionary.com: "insufficient or haphazard; not fully planned or developed"

From Sharry Bobbins

Here's a way of expressing your idea that I have recently come up with in the context of DIY home repairs. I've been wrestling with a problem house and more recently have been househunting, and have been using it a lot.

mickey mouse

I doubt this will be in a dictionary for the usage I've been giving it, but everyone I've tried it with has understood exactly what I meant.

An example sentence, talking about a "staircase" leading to a primitive cellar (it's sturdy but so steep you have to turn around and go down like you go down a ladder):

• Apologies for the steep stairs -- there wasn't enough head room because of the beams right there. It's a little mickey mouse, but it works for getting into the cellar.




• I think the seller finished the attic himself. Look at how mickey mouse this paneling is.

Kludge is the one that immediately came to mind.

Specifically for software there is cruft.

It is used particularly for defective, superseded, useless, superfluous, or dysfunctional elements in computer software.

If you need a verb, to cobble up may fit.

I get what you are trying to convey but personally being somewhat of a tinkerer it wouldn't fit exactly

Tinkering

verb [ I usually + adv/prep ] UK ​ /ˈtɪŋ.kər/ US ​ /ˈtɪŋ.kɚ/
​
to make small changes to something, especially in an attempt to repair or improve it:

He spends every weekend tinkering (around) with his car.
I wish the government would stop tinkering with the health service.

Tinkering

So sometimes tinkering will result in an improvement, gain of knowledge or something else even an innovation, but this part got me thinking that tinkering is presented as a negative thing.

Das ist keine Software, das ist ein Bastel(ei).

Ce n'est pas du logiciel, c'est un bricolage.

(That's not software, that's a ____ )

What your are trying to convey here is that, that software is poor design and quality. Even more is like someone es getting offended just by looking at the code(been there), in which case I'd use the word

MishMash

mishmash
noun [ S ] UK ​ /ˈmɪʃ.mæʃ/ US ​ /ˈmɪʃ.mæʃ/ informal
​
a confused mixture:

The new housing development is a mishmash of different architectural styles.

Synonyms:

Farrago - us formal disapproving

Hodgepodge - us

Hotchpotch - mainly uk

Ragbag

MishMash

Farrago

Meanwhile I believe that Farrago will fit very well as it is a formal disapproval.

Word forms: plural farragoes , plural farragos; countable noun

If you describe something as a farrago, you are critical of it because you think it is a confused mixture of different types of things.

[formal, disapproval]

EG: His own books and memoirs are a farrago of half-truth and outright invention. [+ of]

Farrago

Tinker-toy?

Usually, these describe the materials in an unfinished (still being tinkered with) state, but I'd imagine that the phrase is usable for less serious endeavors.

thrown-together

might work here in the sense of "assembled fast" e.g. "a quickly thrown-together software application"

From macmillandictionary.com:
to make something quickly because you do not have much time

You can call something a hack, as other answers said, but it has strong connotations that it might not work properly.

You could instead say that this solution has been hacked together. Emphasize on the lack of nice paint and finish by adding a time span: hacked together very quickly / in one afternoon.

You may also want to stress how little effort has been spent on the presentation and polishing of the product, and as such call it a quick and dirty effort.

These two words imply less a connotation that this is not a proper solution, but rather try to emphasize that while proper (or even just sufficient), it might lack beauty or elegance. Compare this to a sausage factory (an unappealing process to generate something familiar).

"tweak"
(noun) (informal) a fine adjustment to a mechanism or system.
Source https://www.google.com/search?q=tweak

Specifically about your example sentence -- at the office, I'd usually complete that sentence:

That's not software, that's a prototype.

This is a way to say, "That solution might seem to work, but we can't deliver it to customers."

Software developers are supposed to know the difference between prototyping and professional development, so depending on the context, this can be a subtle, or not-so-subtle jab.

The non-ironic case is when a prototype was created deliberately, and non-technical folks naively want to use it as-is.

Kludge or hack convey the same meaning, but are more aggressive. Prototype is more polite but definitely conveys the point that the software is not built on sound architecture.

Skunkworks - an experimental laboratory or department of a company or institution, typically smaller than and independent of its main research division. Although, skunkworks usually describes the effort involved in tinkering.