--- title: Unilateral vs Bilateral Contracts: The Difference | Aavenir url: https://aavenir.com/unilateral-vs-bilateral-contracts/ description: What unilateral and bilateral contracts are, how they form, examples of each, the key differences and what each means for obligations and compliance. updated: 2026-11-07 --- [Home](https://aavenir.com/) / [Blog](https://aavenir.com/blogs/) / Unilateral vs bilateral contracts Contract basics # Unilateral vs bilateral contracts: what is the difference? One side promises in exchange for an act, or both sides promise in exchange for each other. That small difference changes when obligations begin. MR **Mohamed Reza**Feb 17, 2025 ยท 4 min read Contracts set out the rights and obligations of the parties to a transaction. One useful way to classify them is by who makes a promise. In a unilateral contract, only one party promises, and the promise becomes binding when the other party performs a specific act. In a bilateral contract, both parties promise something to each other. Knowing which one you are dealing with matters for compliance, for securing your rights and for avoiding disputes. This guide explains both types with examples, sets out the key differences and covers how to manage the obligations each creates. It is general information, not legal advice, and the rules vary by jurisdiction. Key takeaways - A unilateral contract is a promise in exchange for an act - A bilateral contract is a promise in exchange for a promise - Most business agreements, from supplier deals to software subscriptions, are bilateral - Unilateral contracts suit rewards, guarantees and incentive programs - Both types create obligations that need clear terms and tracking ## What is a unilateral contract? A unilateral contract is a one sided agreement. One party, the promisor, commits to do something if another party performs a specified act. The other party is not obliged to act at all. If they do, the promisor must keep the promise. ### Examples - **Bug bounty programs:**a software company promises a reward to anyone who reports a qualifying security flaw. The obligation arises only when a valid report is submitted - **Referral programs:**a business offers a discount or credit to customers who bring in a new buyer - **Money back guarantees:**a company promises a refund if a customer is dissatisfied and makes a claim within the stated terms - **Rewards and contests:**a published reward for returning lost property, or a prize for completing a challenge - **Sales bonuses:**a bonus promised for hitting a defined target Insurance policies are sometimes described as unilateral in character, because the insurer's duty to pay depends on an insured event, but in most cases premiums and coverage create commitments on both sides. Classification can depend on how the agreement is written and the law that applies. ### Key characteristics - **One obligation:**only the promisor is bound, and only once the act is completed - **Acceptance by performance:**the other party accepts by doing the act, not by signing - **Clear terms:**the act required and the reward offered must be stated precisely Businesses use unilateral contracts to encourage actions without asking for an upfront commitment. They are flexible for the acceptor, focus effort on a defined goal and cost the promisor nothing unless the condition is met. ## What is a bilateral contract? A bilateral contract is an exchange of promises. Each party commits to do something for the other, and both are bound from the moment the contract is formed, before either has performed. ### Examples - **Supplier agreements:**the supplier promises to deliver goods or services, and the buyer promises to pay - **Software subscriptions:**the provider promises access and support, and the customer promises to pay fees and follow usage terms - **Employment contracts:**the employee promises to work, and the employer promises to pay salary and benefits - **Leases:**the landlord promises use of the property, and the tenant promises rent and care of it - **Master service agreements:**both parties commit to a framework of terms for future work ### Key characteristics - **Mutual obligations:**both parties owe performance - **Binding on formation:**the promises are enforceable once the contract is agreed - **Negotiated terms:**price, scope, service levels, liability and termination are usually negotiated Most of the agreements an enterprise manages are bilateral. See [master service agreement](https://aavenir.com/glossary/master-service-agreement/). ## What are the key differences? | Aspect | Unilateral contract | Bilateral contract | | Who promises | One party | Both parties | | --- | --- | --- | | How it is accepted | By performing the act | By agreeing to the terms | | When obligations start | When the act is completed | When the contract is formed | | Can the other party walk away? | Yes, they never had to act | No, both are bound | | Typical uses | Rewards, guarantees, incentives | Supply, services, software, employment, leases | | Main risk | Unclear conditions lead to disputes about whether the act was done | Missed obligations and breach on either side | **Know every obligation in every contract**See Aavenir AI classify agreements and extract the obligations owed by each party, for your team to approve. Schedule a demo ## Why does the distinction matter? ### Compliance and rights In a bilateral contract you owe performance from day one, so you need to know your obligations as well as the other side's. In a unilateral contract your obligation is conditional, so the condition must be clear enough that you can tell when it has been met. ### Avoiding disputes Disputes in unilateral contracts usually turn on whether the act was performed as required: was the bug in scope, was the refund claimed in time? Disputes in bilateral contracts usually concern whether a promise was kept: was delivery on time, did the service meet the agreed level? Precise drafting prevents both. See [breach of contract](https://aavenir.com/glossary/breach-of-contract/). ### Revocation Questions about when a promisor can withdraw a unilateral offer, especially once the other party has started performing, depend on the governing law. Legal teams should set out revocation terms clearly in programs such as rewards or bounties. ## How should teams manage both types? Whatever the type, the work is the same: store the agreement where it can be found, record the obligations and conditions, assign owners and track performance. A contract repository that classifies agreements by type, and extracts who owes what, makes that practical across thousands of contracts. In [Contractflow](https://aavenir.com/solutions/enterprise-contract-management-software/), Aavenir AI reads each agreement and extracts obligations for both parties, and [Obligationflow](https://aavenir.com/solutions/contract-obligation-management-software/) assigns them to owners with reminders. A person approves every extracted result. ## The bottom line A unilateral contract binds one party when the other performs an act. A bilateral contract binds both parties from the start. Most enterprise agreements are bilateral, but both types need clear terms and tracked obligations to avoid disputes. ### In this article - What is a unilateral contract? - What is a bilateral contract? - What are the key differences? - Why does the distinction matter? - How should teams manage both types? **See obligations extracted for both parties**Bring a sample agreement. Aavenir AI will list who owes what, for your team to approve. Share [in](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Faavenir.com%2Funilateral-vs-bilateral-contracts%2F)[X](https://twitter.com/intent/tweet?url=https%3A%2F%2Faavenir.com%2Funilateral-vs-bilateral-contracts%2F&text=Unilateral%20vs%20bilateral%20contracts%3A%20what%20is%20the%20difference%3F) Frequently asked questions (FAQ) ## Frequently asked questions ### ### What is an example of a unilateral contract? A bug bounty program is a common example: a company promises a reward to anyone who reports a qualifying flaw, and the obligation arises only when a valid report is made. Referral rewards and money back guarantees work the same way. Learn about [contract obligations](https://aavenir.com/glossary/contract-obligations/). ### ### Is a supplier agreement unilateral or bilateral? Bilateral. The supplier promises to deliver goods or services and the buyer promises to pay, and both are bound once the contract is formed. Most enterprise contracts, including software subscriptions and service agreements, are bilateral. See [vendor contract management](https://aavenir.com/glossary/vendor-contract-management/). ### ### Why does the contract type affect obligation tracking? In a bilateral contract both parties owe performance from the start, so you track your own duties and the counterparty's. In a unilateral contract the promisor's duty is conditional, so you track the condition. See [contract obligation tracking](https://aavenir.com/use-cases/contract-obligation-tracking/). Have a question we have not answered? [Ask the Expert](https://aavenir.com/contact/) ## Keep reading [Contract basics What are agile contracts? What agile contracts are, the main types from incremental delivery to time and materials, their benefits and risks, and how to manage them well in 2026. Read more](https://aavenir.com/what-are-agile-contracts/)[Contract risk management Five bad practices to avoid if you want to manage contract risk Five common contracting habits that raise risk, from drafting by hand to forgetting signed contracts, and the better practice that replaces each one. Read more](https://aavenir.com/top-5-bad-practices-to-avoid-in-order-to-better-manage-contractual-risk/)[Contract repository What is a contract repository, and how do you create one? What a contract repository is, how it differs from shared folders, six reasons every business needs one and a step by step plan to build it in 2026. Read more](https://aavenir.com/what-is-a-contract-repository/) Schedule a demo ## See your contracts run on one record. - **1****A 30 minute walkthrough**Built around your team, whether that is procurement, legal, IT or finance. - **2****Your contracts, not ours**Bring a few sample agreements and watch Aavenir AI extract and review them. - **3****ServiceNow or standalone**We show the deployment that fits the systems you already run. Prefer to talk first? [Contact the team](https://aavenir.com/contact/). The form did not load. [Contact the team](https://aavenir.com/contact/) instead, or refresh the page.