Web Application Development: Panels, Portals and SaaS Products
Web application development is the design and build, from scratch, of browser-based software that manages a process specific to your business: an admin panel, customer portal, booking and order system, dealer screen or SaaS product. Specification, interface design, development, testing, deployment and source code handover are all in scope. What an off-the-shelf program cannot do is built in measurable stages with written acceptance criteria.
// Who is web application development for?
Web application development is for businesses running their processes through spreadsheets, messaging apps and email, or that have hit the limits of an off-the-shelf program. The need is usually clear, but no product on the market does exactly that, and stitching two products together by hand produces errors and lost time. If any of the following sounds familiar, you are on the right page.
- Order, booking or application tracking is scattered across spreadsheets and messages
- Customers or dealers keep calling for status updates because they have no screen of their own
- The licence you pay for an off-the-shelf product covers half of what you need
- You want to turn an idea into a product and have no technical team for the first version
We follow the same process for a single-user internal panel and a thousand-user SaaS product; only the number of modules and integrations change.
// What is included and what is not
The project runs against a written specification; no code is written until it is approved. The table below lists what a standard project includes and what stays outside, line by line. Source code and infrastructure access belong to you; there is no licence or annual lock-in fee, and that rule is written in the quote and does not change.
| Work | Standard project |
|---|---|
| Scoping call and written specification (modules, roles, screens, acceptance criteria) | Included |
| Interface design and clickable prototype | Included |
| User management, roles and permissions | Included |
| Module development (staged delivery, every stage tested) | Included |
| External system integration (API connection, up to 2 systems) | Included |
| Reporting screens, exports and security (encryption, sessions, backups) | Included |
| Testing, deployment and server setup | Included |
| Source code, technical document and user guide handover | Included |
| 60 days of bug fixing after delivery | Included |
| Mobile app (iOS/Android) version | Priced separately |
| More than 2 external integrations | Priced separately |
| Server, domain and third-party service subscriptions | Excluded |
If a mobile app is needed it is planned to share the web application's backend; desktop needs are described separately under desktop application development.
// How does it work and how long does it take?
A small internal panel takes 4 to 6 weeks, a multi-module portal 3 to 5 months; the duration is written per module in the specification. Development is delivered in stages: when each module is finished you try it on staging and approve it, so there is no surprise at the end. Bug fixing is guaranteed for 60 days after delivery.
Scoping call (1 week)
The current process, users, screens and integrations are heard and the workflow drawn
Specification and prototype (1 to 2 weeks)
Modules, roles and acceptance criteria are written; a clickable prototype is approved
Staged development (3 weeks to 4 months)
Modules are built in order; each is presented on staging and approved
Integration and testing (1 to 2 weeks)
External systems are connected; security and load tests run
Deployment and handover (1 week)
The server is set up, data migrated, training given, code and documents handed over
// How is the price determined?
Three variables set the price: number of modules and screens, number of user roles and number of external integrations. A 3-screen single-role internal panel and a 12-module, 4-role portal with an accounting integration do not carry the same workload, so we quote from the specification rather than a fixed list. The scoping call is free and the quote is fixed once the specification is approved; it is also broken down per module.
The price does not rise during development; if the scope changes, extra work is added with written approval. Payment is split across module deliveries. The source code is yours; there is no licence or annual fee.
// Results we have delivered
The three cases below represent different application types. We do not share client names without permission, so sector and scale are given instead; figures come from delivery reports and client measurements. All three applications were delivered in stages by Zep Bilisim and the source code stayed with the client.
- Logistics company, dispatch panel — Dispatch tracking run through spreadsheets and messaging was moved to a panel in 6 weeks; 3 hours of daily manual entry disappeared and faulty dispatches fell from 9% to 1%
- Education provider, student portal — Enrolment, payment tracking and document requests were gathered in one portal; status calls fell from 400 to 60 a month
- Dealer network, order portal — 40 dealers place orders and see stock from their own screens; order processing fell from 2 days to 2 hours, with automatic export to the accounting system
An off-the-shelf product forces your business into its mould; a custom application cuts the mould to fit your business. The difference shows not in the first month but in whether you are still using it in year three.
// The team behind the work
The project is led by Caner Zep Çelik, founder of Zep Bilisim. As founder and technical consultant he has worked on software architecture, web application development and API integrations since 2020 and has been involved in more than 100 projects. He writes the specification, sets the architecture and reviews the code himself, and delivers every module together with the development team.
The technical document is written by the same person: architecture, data structure, integrations, deployment and update steps. The document lets another team take over the code later and stays with you.
// When is it not needed?
If a well-known off-the-shelf product covers 90% of your need, a custom application is wasted money; we say so plainly in the scoping call and recommend the product. If the process has not settled yet, with rules changing every week, it is better to stabilize the process first and then build; software written too early is obsolete in two months, and we say so in the call.
If the need is only a small function on a WordPress site, a custom plugin is cheaper and we set that order accordingly.
OWASP's web application security Top 10 lists, from an independent source, the security risks we check in every application we build; our testing step is built on it.
// Frequently Asked Questions
Widely used, well-documented, long-lived open-source technologies are chosen per project, with the reasoning written in the specification. The aim is that another developer can read and maintain the code; niche tools dependent on one person are not used. Hosting is set up in your own account, so access and cost control stay with you.
Yes. When each module is finished it is presented to you on staging; you try it and approve it or request corrections. A written weekly progress summary is sent. That way you never meet an unexpected screen at the end; a module that is not approved is corrected before the next one starts. Payment is also tied to module deliveries and announced in advance.
Yes; data from spreadsheets, an old program or a database is cleaned and moved into the new structure as part of the deployment step. A trial run with sample data is done first and the result shown to you. A parallel-running period with the old system can be planned on request; the transition happens without data loss and a checklist is handed over.
Yes, completely. The code, database structure and infrastructure access are handed over at deployment, with no licence restriction or annual fee. You can continue with another team or add your own developer. The technical document is written to make that handover easy; the in-code comments are in plain language and the version history is delivered.
Bug fixing is free for 60 days after delivery. After that, new feature requests are quoted separately, while server monitoring and security updates come with a monthly maintenance plan. We maintain applications we built years later too; the technical document and version history make that continuity easy and any new quote is based on the same document.
Yes, but in writing. Every new request after the specification is approved is written up as extra work with its duration and cost and added to the plan if approved. Small corrections do not count as extra work. This discipline prevents open-ended projects and surprises outside the quote, and staged delivery makes the scope visible early.
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