KISS
/kɪs/
CommonKeep It Simple, Stupid. The best solution is usually the simplest one that works.
The 'Stupid' in KISS is directed at the designer, not the user. It's a reminder to check yourself before adding layers. Some versions use 'Straightforward' instead.
Real-world examples4 examples
| # | Example | What it means | Source |
|---|---|---|---|
| 01 | you don't need a state machine for a two-step form. KISS. | The proposed solution is much more complex than the problem demands. | x, 2024 |
| 02 | new engineer asked why we use a flat JSON config instead of a YAML schema with inheritance. KISS. we've had zero config bugs in 3 years. | Simple solution working reliably over time justifies not adding complexity. | reddit, 2023 |
| 03 | I fight the urge to add abstractions every day. KISS is a discipline not an instinct. | Keeping things simple requires active effort, especially for experienced engineers. | x, 2024 |
| 04 | the KISS principle saved us. rewrote the service as a single function. deploys in 3 seconds. 0 incidents in 6 months. | Radically simplifying a service led to measurable reliability and operational gains. | x, 2023 |
Use it when
- Someone proposes a complicated solution when a simple one would work.
- A code review where the implementation is hard to follow for no reason.
- Arguing for a simple deployment over a complex pipeline.
Do not use it when
- The complexity is genuinely required by the problem.
- You just mean you prefer less code.
KISS vs DRY
KISS
KISS says don't add complexity without reason.
VS
dry-principle
DRY says don't duplicate knowledge across the codebase.
Origin and context
Attributed to Kelly Johnson, lead engineer at Lockheed's Skunk Works in the 1960s. He handed engineers a set of basic tools and said an aircraft should be repairable with those tools in the field. The principle moved into software engineering and became standard vocabulary.
- First seen
- 1960s
- Confidence
- medium
Cite this page
Use this stable URL to reference the entry.
https://slang.fyi/kiss-principleUpdated: 2026-08-28License: CC BY 4.0