Unilateral Amendment Clause

What is a unilateral amendment clause?

A unilateral amendment clause is the part of a contract that lets one side change the terms on its own, without the other side signing anything. In vendor contracts, that side is usually the vendor. "Unilateral" just means one-sided.

It is the clause behind the familiar line "we may change these terms at any time." It also goes by "modification clause" or "changes to these terms."

Vendors use it because they serve thousands of customers on the same terms of service. Signing a new deal with each customer for every update would not work. The clause lets them update one document for everyone.

What it looks like in a vendor's terms

A typical clause reads like this:

We may modify these Terms at any time. We will post the updated Terms on our website and, for material changes, notify you by email. Changes take effect on the date shown. By continuing to use the services after that date, you agree to the updated Terms.

• "Modify these Terms at any time": the vendor gives itself the right to change the deal.
• "Post the updated Terms": the new version goes live on a web page, often with no other announcement.
• "For material changes, notify you": only changes the vendor sees as important get an email. See material change.
• "Take effect on the date shown": the effective date, when the new rules start to apply.
• "By continuing to use": you are treated as agreeing just by staying. See continued use as acceptance.

The GitHub Terms of Service are a real example: GitHub says it may "amend these Terms of Service at any time" and gives 30 days' notice of material changes.

Why courts do not accept it without limits

Basic contract law says one side cannot rewrite a deal alone. As the ABA's Business Law Today puts it, a proposed change is treated as an offer that binds no one until it is accepted. Acceptance generally needs notice and some sign of agreement.

US courts have applied this to online terms. In Douglas v. U.S. District Court (9th Cir. 2007), a long-distance phone provider posted new terms on its website, including an arbitration clause. The customer was never told. The court held he was not bound, because he could not accept an offer he did not know about.

There is a second problem. If a vendor can change anything at any time with no notice, some courts may find its promises were never real. Morgan Lewis says one-sided changes "can render the contract illusory and unenforceable," meaning the promises may not count as a real contract. It also says terms of use cannot be updated retroactively, so new terms should not reach back to the past. See retroactive terms changes.

The result depends on the state, the facts and how the notice was given. A clause with clear notice and a fair chance to leave is on much firmer ground than one that says "at any time, without notice."

A good version and a bad version

The weaker version for you lets the vendor change anything by posting and expects you to keep checking. The AWS Customer Agreement says changes take effect on posting, or as stated in an email, and that it is your responsibility to check the site regularly.

A better version limits when and how changes apply. The Atlassian Customer Agreement says that for paid subscriptions, most changes take effect at your next order or renewal. Changes needed for legal compliance or product updates can apply sooner, and then you may end the rest of your term for those products and get a refund of prepaid fees.

Signs of a good clause:

• Advance notice, by email, of a stated number of days.
• Changes apply at renewal, not mid-term.
• A right to cancel with a refund if you object.
• No changes that apply to past events or disputes.

A real change we caught

Venpo flagged a change that brought this clause into a data contract: Hotjar's DPA can now change without your signature. A data processing agreement sets the rules for how a vendor handles personal data for you. Hotjar's DPA, now published by Contentsquare, used to say changes needed the written agreement of both sides. Since June 2026 it says Contentsquare can change it "at any time and in its sole discretion." Once a DPA can change one-sidedly, the data protections you checked at signup can shift later.

Why it matters to you

This clause is how most other changes reach you. Price rules, AI training, data retention, liability caps and dispute terms can all change through it.

It also limits the value of any review you did at signup. You checked one version. The version that binds you a year later may be different. If you told your own customers how their data is handled, a vendor change can make those statements wrong.

What to check

• Whether the vendor can change the terms by posting alone, or must email you.
• How many days of notice it promises, and for which changes.
• Whether changes apply mid-term or only at renewal.
• Whether you can cancel and get a refund for unused prepaid time if you object.
• Whether the clause also covers linked documents, such as the DPA or acceptable use policy.
• In a negotiated contract, ask that changes bind you only if both sides sign, or only from your next renewal.

Contract amendment

A contract amendment is a formal change to a contract that both sides agree to, usually by signing a short document. It is the opposite of a unilateral change.

An amendment typically names the original agreement, lists the exact sections it changes, states when the change starts and carries both signatures. Larger contracts, such as a master service agreement, often say they can only be changed this way.

An amendment is not the same as an addendum. An amendment edits terms that already exist. An addendum adds something new, such as a security exhibit, while leaving the rest in place. See amendment vs addendum.

If you signed a negotiated contract, check whether it says changes need a signed amendment. If it does, a vendor's later update to its online terms may not override what you signed. Look for wording like "may be modified only in a writing signed by both parties."

How Venpo helps

A unilateral amendment clause means your vendors can change the deal at any time. Venpo watches their public terms, privacy policies, DPAs and other legal pages and emails you a plain-English alert when one changes, with what changed and why it matters.