Web App Development Cost: Scope Matrix

Published by Bles Software, a custom software and AI company based in Yehud-Monoson, Israel, building web apps, AI agents and API integrations for clients in Israel, the US, the UK and the EU.

A web app scope matrix, with the build-or-buy call on every row

Web app estimates vary by a factor of ten because "web app" covers a form that emails you and a multi-tenant product with audit logs. This page is a matrix instead of a range: four scope tiers, the decisions that move you between them, and then a component by component build-or-buy call with the published price of buying each. Prices were read on 9 October 2026.

Place yourself on the matrix first. The tier you are in is set by three questions and nothing else: does it have accounts, does it take money, and does somebody else's compliance team have to approve it.

The four tiers

Moving from tier one to tier two is the biggest single jump in this matrix, and it is not the sign-in box. It is the permissions model: every screen, every API route and every export now has to answer "who may see this" consistently, and that question is answered in every file you write afterwards. Moving from three to four is the second biggest, and it is not a feature at all, it is the obligation to prove things to a stranger.

The components, and what buying each one costs

Most of a tier two or three app is assembled, not written. Here is what the assembly costs at list price, which is the number to put against your own hours.

Identity. Auth0 is free to 25,000 monthly active users, then Essentials from $35 a month for business-to-consumer and $150 a month for business-to-business at 500 MAU, and Professional from $240 and $800 a month respectively at the same user count [1]. Clerk is free on Hobby to 50,000 monthly retained users, then $25 a month on Pro or $20 billed annually, and $300 a month on Business or $250 annually, with per-user pricing of $0.02 a user-month above 50,000 falling to $0.018 above 100,000 [2]. AWS Cognito includes 10,000 monthly active users free on Lite and Essentials, then charges $0.0055 per MAU on Lite for the first 100,000 above the free tier and $0.0046 after, $0.015 per MAU on Essentials and $0.020 on Plus with no free tier [3].

Read the unit, not the price: Auth0 and Cognito meter monthly active users, Clerk meters monthly retained users [1][2][3]. For an app where people sign in twice a year those are very different bills.

Payments. Stripe is 2.9% plus 30¢ per successful transaction on domestic cards, with 0.5% added for manually entered cards, 1.5% for international cards and 1% for currency conversion [4]. Nothing to build at tier three means nothing except the reconciliation, which is yours.

Email and SMS. AWS SES is $0.10 per 1,000 emails à la carte plus $0.12 per GB of attachments, with plan-based rates from $0.16 per 1,000 on Essentials [5]. Postmark is $15.00 a month for 10,000 emails with overage at $1.80 per 1,000, rising through Pro at $16.50 with $1.30 overage and Platform at $18.00 with $1.20 [6]. Twilio is $0.0083 per 160-character SMS segment in the United States, outbound and inbound, with carrier fees extra and varying by carrier [7].

That carrier-fee footnote is the one that catches budgets: the published per-segment price is not the delivered price [7].

Error tracking. Sentry is free for one user and 5,000 errors, $26 a month billed annually on Team with 50,000 errors, and $80 a month on Business at the same error volume [8].

Where it runs, and the meter each host uses

Four different meters sit in that list: requests, credits, CPU time and compute units [9][10][13][14]. The practical consequence is that a prototype is nearly free everywhere and the ranking changes completely at scale, so pick for the shape of your traffic rather than the headline plan price.

Tier four, where the cost stops being features

At tier four you are buying evidence, and three published standards set what the evidence must show.

WCAG 2.2 became a W3C Recommendation on 12 December 2024, with conformance levels A, AA and AAA [16]. The United States Department of Justice published its final ADA Title II web rule in the Federal Register on 24 April 2024, requiring WCAG 2.1 Level AA, with compliance dates of 26 April 2027 for populations of 50,000 or more and 26 April 2028 for smaller entities and special districts, and an interim final rule adjusting those dates published on 20 April 2026 [17]. That rule covers state and local government, not private companies, which is a distinction vendors routinely blur when selling accessibility work.

Performance has published thresholds too, and they are pass or fail rather than advisory. Google's Core Web Vitals targets are a Largest Contentful Paint within 2.5 seconds, an Interaction to Next Paint of 200 milliseconds or less, and a Cumulative Layout Shift of 0.1 or less, each measured at the 75th percentile of page loads and segmented across mobile and desktop [18]. The 75th percentile is the part estimates miss: your fast desktop load does not count, the slow quarter of your real traffic does.

What moves a number up, and what moves it down

Up, in order of how much:

Down, in order of how much:

The labour under all of it is public: the United States Bureau of Labor Statistics puts web developers (15-1254) at a mean $47.49 per hour and $98,770 a year, and software developers (15-1252) at a mean $71.20 per hour and $148,100 a year, in its May 2025 survey [19]. Which of the two your work actually is explains most of the difference between two quotes for the same brief.

Sources

More Costs and Timelines from Bles Software