It's a truism that (many) developers are not good writers. And it's not just style or composition, it's grammar. This has always puzzled me, since if a programmer makes a grammar mistake (using a backtick instead of an apostrophe, for instance), the program won't run. Maybe the problem is that they don't pay attention to the red squigglies in Word.

Arguably the worst error I see is wrongly using an apostrophe when "its" is possessive. Here's a sentence to illustrate. Every apostrophe is correct.

Harvey's car's in the shop to have its radiator fixed before it's blown to bits.

Expand the contractions and the differences between possessives and contractions are clear. Harvey's car is in the shop to have its radiator fixed before it is blown to bits.

Here are three rules that, if followed, would take care of about 70% of the most grievous errors I see in blog posts, emails, business proposals, and technical documentation.

I even made a fancy PDF.

Grammar for Developers - Apostrophes

3 Simple Rules

  1. Never make a pronoun possessive using an apostrophe
  2. Always make a noun possessive using an apostrophe
  3. Never use an apostrophe with a verb

3 Common Mistakes

Right: Unit testing has its benefits.
Wrong: Unit testing has it's benefits.

Right: Carol's code is clean. Her code's style is precise.
Wrong: Carols code is clean. Her codes style is precise.

Right: He runs that backup every day.
Wrong: He run's that backup every day.


A noun is a specific person, place, thing or idea: Carol, France, house, radish, memory, Chipotle.

A pronoun is a generic, non-specific person or thing. These are the common pronouns: it, he, she, her, them, they.

A verb is an action taken by the subject. He codes. She tests. They demonstrate.