Whether you’re creating a simple website for a startup or building a complex information system, skipping proper requirement documentation can lead to serious issues down the road. In this article, we’ll explain why preparing a technical specification is a mandatory step and a strategic advantage in the development process. And also we will share how we approach it in our projects.
What is a technical specification for web development?
A technical specification document (TSD) defines all the client’s expectations and technical requirements for the future product. It describes everything that should be implemented in the project and serves as a common communication layer between managers, developers, and the client.
Before development begins, we recommend allocating time and resources to creating detailed requirements, especially for large or scalable projects. The document outlines all the product’s functionality and the full scope of work. Based on this, we can create an accurate cost estimate and project plan.
Later, the TSD becomes a guide for the development team. While requirements can be clarified or expanded as the project evolves, the system foundation is set in this initial specification.
In short, a well-written technical specification document guarantees transparency for both sides:
- the client knows exactly what outcome to expect,
- the team can work efficiently without constant revisions.
Flexible approaches: fixed price vs. time & materials
If flexibility matters to you, we support both fixed-price and time and materials (T&M) models.
Even in T&M projects, we still create a software development requirements document to keep everyone aligned but we remain flexible to adjust if priorities shift.
The difference lies in payment: in T&M, we track the actual time and resources spent, and the client pays based on real effort.
How we create requirement documentation
Depending on the project’s type, complexity, and how much information the client already has, our process may vary.
For instance:
- If you’re a startup without a clear product vision, we’ll help shape it iteratively through workshops and briefs. It takes time, but this approach ensures a shared understanding and a product that fits your goals perfectly.
- If you already have documentation, prototypes or an existing product, we’ll review everything, refine the requirements, propose technical solutions, and align on the final project vision.
Still, most OnePix projects follow these three core stages. Depending on complexity and feedback speed, preparing the TSD usually takes 2 to 6 weeks (and up to 2 months for very large systems).
Stage 1: gathering initial requirements
We start with your project request and first discovery calls. You share your vision, and we capture all software development requirements and clarifications.
Our analysts then review this information and, if needed, hold online meetings to dive deeper. Based on these sessions, they create the initial structure of the technical specification, outlining major functional blocks of the system.
To speed up this stage, it helps if you already have a rough idea of your product’s structure and expectations before submitting the request.
⏱ Typical duration: 1–2 weeks
Stage 2: iterative refinement
We work on the specifications iteratively, involving you throughout the process. This allows us to fully understand your business and propose the best solutions.
Analyzing requirements and drafting the document
After the initial structure is ready, we review it together and move on to describing specific functions and features.
At this stage, many questions arise — we address them through comments, chat messages, or quick calls.
Iterations and adjustments
We refine the draft through multiple iterations, integrating your feedback each time until we reach a shared, complete vision of the final document.
⏱ Typical duration: 1–3 weeks
Stage 3: approval and project kick-off
Once the technical specification is fully detailed and no open questions remain, both parties sign it. This document becomes the foundation for budgeting, development, and performance evaluation.
If we later need to add non-critical updates or new features, we’ll list them in a backlog and estimate them separately after completing the initial TSD scope.
This structured approach keeps development efficient and predictable, helping us deliver results faster.
What a technical specification document looks like
While the structure varies depending on project type, the underlying logic stays the same.
For eCommerce websites, the requirement documentation typically includes detailed descriptions of:
- shopping cart functionality,
- checkout flow,
- payment gateways,
- user accounts,
- referral and bonus programs,
- delivery mechanisms.
For information systems, the focus shifts to user roles, dashboards, and third-party integrations.
A well-prepared technical requirements document usually includes:
System architecture
A high-level overview of the system’s structure: user types, number of pages, and overall logic that ensures a seamless user experience for each audience group.
Design and functional requirements
We describe what should happen on each page from a user’s perspective — how buttons, blocks, forms, and features like “add to favorites” or “quick order” should behave.
Functional requirements for each module
This section explains how processes work from a business standpoint: how to collect user data for order placement, how reviews are stored, or how the favorites list operates.
External integrations
Here we describe all third-party systems that need to be connected — CRM, ERP, and payment gateways.
Integrations are often the most complex part of development, requiring careful analysis and precise documentation. Depending on the business logic, they may take anywhere from 50 to 500 hours to implement.
That’s why we thoroughly define this part of the requirement documentation before starting development to prevent surprises later.
Non-functional requirements
This section defines general quality attributes of the system: reliability, scalability, security, and data management — ensuring the product is stable, safe, and efficient.
Get acquainted with our portfolio to see the examples of integrations and other implemented features:
Can you develop without a technical specification?
Technically, yes — but only in specific cases.
Sometimes, for long-term clients who need small updates, we can skip a formal specification document and define the software requirements on a quick call.
However, for large projects, skipping this stage is risky:
- the budget and scope remain unclear,
- parallel discussions about design, backend, and frontend create chaos,
- and as a result, deadlines, costs, and expectations blur — the client often gets something different from what they imagined.
That’s why we’ve built a dedicated analytics team and integrated a full requirement documentation phase into our workflow.
Examples from practice
We’ve had successful cases even without a technical specification document — for example, with Uctel, who came to us for a website redesign. They provided a reference and color palette, and our project manager and designer built a layout in Figma based on selected references.
It worked — but it required significant alignment effort from the PM. Even with a technically skilled PM, the risk of scope creep or misunderstanding remains high.
Later, Uctel came back with a more complex project — a mobile app for signal testing — and that time we worked iteratively with proper requirement documentation.
In most cases, projects that start without a TSD end up needing one mid-process to keep things on track. This experience taught us to think strategically and emphasize the technical specification preparing stage for all clients.
Key takeaways
- A technical specification helps plan the project precisely — defining tasks, budget, and timelines from the start.
- We adapt the process to each client — from startups to complex enterprise systems.
- For large projects, creating proper requirement documentation is essential to reduce uncertainty and ensure predictable results.
- We develop TSDs iteratively, involving clients throughout the process for full transparency.
- The document serves as a mutual guarantee — ensuring budget control, on-time delivery, and a clearly defined outcome.
