A contract is a legally enforceable agreement between two or more parties that creates mutual obligations to do or not do something.
In a court case, a contract appears as a written or oral promise that the plaintiff claims the defendant broke (breach of contract). The court examines whether the parties actually agreed, whether something of value was exchanged (consideration), and whether the terms are clear enough to enforce. Evidence of the contract—such as a signed document, emails, or testimony about a handshake deal—is presented to prove its existence and terms.
If you are sued for breach of contract, the court will decide whether you made a valid promise and failed to keep it, which could result in you having to pay damages or perform the promised action. Conversely, if you are the plaintiff, you must prove that a contract existed and that the other side violated it to get a remedy.
Many people think a contract must be written and signed to be valid, but oral contracts can be enforceable in many situations. However, certain types of contracts (like those for real estate or agreements lasting more than a year) legally require a written document under the fraud laws.
Get the actual rule
This page explains the concept. When it matters to your case, read the rule that governs it in your court — we hold Texas, federal and Washington court rules word for word, and every state's official resources are on the state pages. If someone cites a case at you, check that it exists first.
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General explanation, not legal advice, and not specific to any state — procedures and deadlines vary by jurisdiction and court. If you can get a lawyer or free legal aid, do: every real option.