not invented here
/nɒt ɪnˈvɛntɪd hɪər/
CommonThe bias toward building something in-house rather than using an existing external solution.
Sometimes there are legitimate reasons to build in-house, like security, control, or specific requirements. NIH is when the refusal isn't about logic. It's about pride or distrust of external work.
Real-world examples4 examples
| # | Example | What it means | Source |
|---|---|---|---|
| 01 | they spent six months building their own ORM because the existing ones 'weren't good enough'. NIH syndrome in full effect. | The team rejected mature tools and built an inferior replacement out of preference. | x, 2024 |
| 02 | our internal build tool is a worse version of webpack that only two people understand. pure not invented here. | A custom tool was built in-house that is inferior to the standard it replaced. | reddit, 2023 |
| 03 | why are we writing a custom auth system instead of using an auth provider. not invented here is going to kill this project. | Rebuilding security infrastructure from scratch is risky and unnecessary. | reddit, 2024 |
| 04 | every startup has that one engineer who wants to rewrite everything from scratch. NIH dressed up as technical vision. | The desire to rebuild existing tools is framed as innovation but is often just bias against external work. | x, 2023 |
Use it when
- A team rebuilds a well-known library from scratch for no technical reason.
- An organization refuses to use an industry-standard tool and maintains their own version.
- Someone rejects an open-source solution without evaluating it, just because it's external.
- A company spends months building something that already exists.
Do not use it when
- There are real technical, security, or compliance reasons to build in-house.
- The existing solutions genuinely don't meet the requirements.
Variations and related forms
Not invented here vs cargo cult programming
not invented here
Not invented here refuses to use external solutions and builds in-house instead.
VS
cargo-cult-programming
Cargo cult programming blindly copies external patterns without understanding them.
Origin and context
Emerged in corporate R&D contexts in the mid-20th century to describe organizational resistance to external innovations. Entered software culture broadly by the 1980s and became a standard term in developer discourse.
- First seen
- mid-20th century
- Confidence
- medium
Cite this page
Use this stable URL to reference the entry.
https://slang.fyi/not-invented-hereUpdated: 2026-08-29License: CC BY 4.0