A short, friendly way to say congratulations.

to say 說 congratulations 恭喜 的一種 a short, friendly way 簡短、親切的說法

You throw it at someone when something good has happened for them: they passed a test, got a new job, got married, had a baby, won a match.

when something good has happened for them 當某人有好事發生時 — they passed a test 通過了考試、got a new job 找到新工作、got married 結婚、had a baby 生了小孩、won a match 贏了比賽 — you throw it at someone 你就會這樣對他說

In speech, texts, and casual cards it is extremely common; younger speakers use it all the time. Though actually it still feels too light for a formal letter, a speech at a ceremony, or anything official — there you want the full word congratulations.

in speech, texts, and casual cards 在口語、簡訊和輕鬆的卡片裡 it is extremely common 非常常見；younger speakers 年輕人 use it all the time 常常在用。Though actually不過事實上, for a formal letter, a speech at a ceremony, or anything official 對正式的信件、典禮致詞，或任何正式場合來說，it still feels too light 感覺還是太輕，there you want the full word congratulations 這時候要用完整的 congratulations 才行。

It works as a little shout on its own (Congrats!) and as a noun (He sent his congrats). People almost never say congrat in the singular in ordinary English.

on its own 單獨使用 it works as a little shout 可以當作一聲歡呼（Congrats!），and as a noun 也可以當名詞用（He sent his congrats）。in the singular 用單數形式 congrat, people almost never say 幾乎沒人會這樣說 in ordinary English在一般英文裡。

A very usual pattern is congrats on + the thing: Congrats on your new baby.

A very usual pattern is一個很常見的固定用法是 congrats on + the thing「congrats on + 事情」：Congrats on your new baby恭喜你生小孩。