How to compare software development quotes line by line

In short: two quotes for the same software project can differ by a factor of two or more, and the cheaper one is rarely the better deal. The difference usually comes from what each vendor assumed was in scope. To compare quotes line by line, give every vendor the same written scope, then check each quote against the same eight lines below. In one real case, quotes of $18,000 and $47,000 for the same mobile app were explained by 60% of the product being missing from the cheaper one.

Why quotes differ so much

Without a written scope, a vendor quotes what they imagine. The gap between what they imagined and what you meant gets settled later as a change request, at your expense. That is not dishonesty; it is what happens when the brief is a conversation. In the case above, the cheaper quote had scoped no offline mode, no role management and no admin back-office. The specification, which took eight days to write, turned an unreadable decision into an obvious one.

Step 1: make the quotes comparable before you compare them

1. Write the scope once: ranked requirements, roles, data to migrate, and an out-of-scope list. The PRD template shows how.
2. Send the same document to every vendor, and ask them to quote against it, listing assumptions.
3. Ask for the quote broken down by feature or phase, not as one number.

Step 2: the eight-line comparison grid

Line	What to look for
1. Scope coverage	Every must-have requirement appears. Missing lines are the most common reason for a low price.
2. Roles and admin	Back-office, roles and permissions are priced, not "included".
3. Data migration	Who migrates and cleans existing records, and is it a priced line?
4. Non-functional work	Security, performance, backups, monitoring. Often absent from low quotes.
5. Testing and acceptance	Who tests, against which written criteria, and how many rounds of fixes are included?
6. Assumptions	A good quote lists them. A quote with none has hidden them.
7. Change process	How a change is costed and approved.
8. Ownership and exit	Code, accounts and documentation handover. See the contract checklist.

Reading the numbers

• Both quotes are cheap: the scope is probably smaller than you think. Check line 1.
• One is much lower: find the missing 30–60% of the product before celebrating.
• One is much higher: ask what is included that the others left out, and whether you need it in version one.
• Similar prices, different timelines: the team size or the amount of testing differs.

When the estimate itself is wrong

A founder arrived with a vendor estimate of 45 days for a multi-tenant SaaS backend. The estimate assumed a single-tenant data model; the multi-tenancy the product needed had not been priced. The gap was about 25 developer-days. Ask each vendor to state their architectural assumptions in writing, especially tenancy, roles and integrations.

If you want a neutral check

I write specifications and review quotes without bidding on the build, so the reading stays neutral. The Technical Specification & PRD offer produces the document vendors quote against. For one vendor proposal and one decision, the Architecture Power Hour is one prepared hour with a written decision record.