Software Development Contractとは何ですか？

Software development contracts come in two primary structures. Fixed-price contracts specify a defined scope of work for a fixed total price — the client knows the cost upfront, but changes to scope require formal change orders and the developer bears risk if the project takes longer than estimated. Time-and-materials (T&M) contracts bill by the hour or day with an estimated budget — more flexible for evolving requirements (common in Agile development), but the client bears cost uncertainty. Most real-world engagements blend both: a fixed-price discovery or scoping phase followed by a T&M or sprint-based build.

The most critical provisions in a software development contract concern intellectual property ownership. Without an explicit IP assignment clause, the developer — not the client — may legally own the code under copyright law in many jurisdictions. The contract must clearly state whether the client receives full ownership of all work product (a 'work-for-hire' or 'assignment of rights' clause), or only a license to use the software. Related provisions include: which party owns the underlying development tools, frameworks, and pre-existing code the developer brings to the project; whether and how the developer can reuse components in future projects for other clients; and what happens to source code in escrow if the developer goes out of business.

Other essential contract provisions include: detailed scope and requirements documentation (vagueness is the primary source of disputes), acceptance criteria (how deliverables are tested and approved), payment milestones (tied to deliverables, not arbitrary dates), warranties and defect correction periods, confidentiality obligations, termination conditions, and governing law and dispute resolution (arbitration vs. litigation).