If you have started exploring custom software development in London, you have already run into the first problem: nobody gives you a straight answer on price. Agencies publish polished portfolios and case studies but the moment you ask what something actually costs, the conversation becomes vague. This guide fixes that.
Below you will find realistic cost ranges in GBP broken down by project type, honest timelines, the questions to ask when briefing a developer, and a clear framework for deciding whether bespoke software is the right call at all. This is written for London-based business owners and operations directors who have budget to spend but want to spend it wisely.
Custom software is any application built specifically for your business, from scratch, to your exact requirements. It is the opposite of off-the-shelf SaaS products like Xero, Salesforce or Shopify, which are built for a broad market and customised only within their own limits.
Bespoke software can be a web application, a mobile app, an internal operations tool, a client-facing portal, an integration layer between two systems, or an automated workflow engine. What all of them have in common is this: the codebase belongs to you, the logic reflects your exact process, and nobody else runs the same product.
SaaS tools are fast to start. You sign up, configure settings, and get moving within days. The trade-off is that you eventually hit a wall: a feature the tool does not support, a workflow it cannot replicate, or a pricing structure that becomes painful at scale. Custom software removes those walls but takes months rather than days to build.
This is the most important section in the guide. Many London businesses commission custom software when an existing SaaS product would serve them better. The reverse is also true: some businesses stay on patchwork SaaS stacks for years, losing hours of productivity daily, when a bespoke tool would have paid for itself inside twelve months.
The honest advice: start with SaaS plus a good automation layer. If you are still hitting walls after six months of genuine use, you have a real case for bespoke.
London agency day rates in 2026 range from around £500 to £1,200 per day depending on the seniority of the team and the agency's specialism. Offshore or nearshore teams working through London agencies typically come in at £250 to £600 per day. Freelancers sit somewhere in the middle at £350 to £800 per day.
Here is what those rates translate to in real project costs:
A bespoke integration connecting two or three SaaS platforms via API, with custom business logic and an admin interface. Examples: a tool that syncs your CRM with a bespoke invoicing system, or an automated onboarding workflow that triggers across Slack, HubSpot and your project management tool. Timeline: six to twelve weeks.
A web application used by your own team: a job management system, a bespoke CRM, a client portal with role-based access, or an internal reporting dashboard. Includes user authentication, database design, admin panel, and basic API. Timeline: three to seven months.
A product that your clients interact with directly: a marketplace, a booking platform, a SaaS product for your industry, or a self-service client portal with transactional functionality. Includes front-end design, complex back-end logic, payment integration, and security hardening. Timeline: five to twelve months.
A native or cross-platform mobile app (iOS and Android). Cross-platform builds using React Native or Flutter sit at the lower end. Native builds for each platform are at the top. Add 20 to 30% for App Store submission, testing on real devices, and ongoing OS update maintenance. Timeline: four to ten months.
A full product with multiple user roles, AI features (document processing, predictive analytics, LLM-powered interfaces), complex integrations, multi-tenancy, and production-grade infrastructure. These projects often run for twelve to twenty-four months with a team of three to six developers. Timeline: twelve months plus.
Timelines quoted by agencies usually refer to active development time, not calendar time. Factor in two to four weeks of discovery and specification at the start, plus a two to four week testing and sign-off phase at the end. A project quoted as a three-month build realistically lands in five to six months from initial briefing to live.
These assume a reasonably clear brief at kick-off. Poorly scoped projects can double in length. This is covered in detail in the next section.
A weak brief is the single biggest cause of budget overruns. Agencies price from uncertainty: the more ambiguous the specification, the larger the contingency they bake in. A precise brief reduces your cost and delivers a better product.
If you cannot write a brief at this level of detail, the discovery phase (where an agency helps you define the scope) is worth paying for before committing to a build. A well-run discovery phase typically costs between £3,000 and £15,000 and saves multiples of that cost during the build.
London has hundreds of development agencies. The quality range is enormous. Here is what separates the ones worth working with from the ones that will cost you time and money.
An agency with three deep case studies in your industry is more valuable than one with twenty shallow ones. Look for projects of a similar type and complexity to yours. Ask specifically what the agency built (not just maintained) on each project.
Any agency worth hiring will insist on a discovery or specification phase before quoting a fixed price. If an agency quotes a £60,000 fixed price from a one-page brief without any discovery, they are guessing. The number will change. Either they will come back with change requests mid-project, or they will cut scope to stay within budget.
Your point of contact should be able to explain technical decisions in plain language. If every question about architecture or timeline gets deflected with "leave that to us," that is a sign of a team that does not trust clients to understand - which means you will not understand what you are paying for.
Ask explicitly what happens after launch. Who maintains the application? What is the SLA for bug fixes? Is there a retainer option? Is source code handed over? Who owns the infrastructure? These questions reveal a lot about how the agency thinks about the relationship.
Ask about the test coverage on the codebase. Automated tests are the cheapest insurance against regressions. An agency that does not write tests is handing you a maintenance liability. Ask specifically: what percentage of the codebase will have automated test coverage at handover?
Understanding the stages helps you hold a project accountable at each phase rather than waiting until delivery to find problems.
Agencies like Softomate Solutions follow a structured discovery-led process before any line of code is written - it is worth asking any agency you speak to how their specification phase works before you commit.
Custom software does not stop costing money when it goes live. Budget for these ongoing costs from the start:
A project that costs £60,000 to build typically costs £8,000 to £15,000 per year to maintain at a basic level. Factor this into your ROI calculation before you commission the build.
London custom software projects typically range from £8,000 for a basic automation tool to £250,000 or more for a full enterprise platform. A standard internal web application usually falls between £25,000 and £80,000. The main cost drivers are project complexity, the number of integrations required, and whether you choose a London-based team or an offshore team managed from London.
Active development for a mid-sized web application typically takes three to five months. Add two to four weeks of discovery at the start and two to four weeks of testing and sign-off at the end. From first meeting to live product, most projects take five to nine months. Complex platforms with AI features or multi-tenancy take twelve to twenty-four months.
SaaS (Software as a Service) is a ready-made product you subscribe to and configure within its limits - Xero, Salesforce, Shopify. Custom software is built from scratch to your exact specification. You own the codebase and the data. Custom software has higher upfront cost but no per-seat licensing, no ceiling on what it can do, and no risk of the vendor changing pricing or discontinuing the product.
For projects under £25,000, a senior freelancer or small team is often the most cost-effective option. Above that, an agency typically offers more resilience (no single point of failure if your developer gets ill or moves on), cleaner processes, and better ongoing support structures. The risk with agencies is overhead cost; the risk with freelancers is availability and continuity. In either case, always check references before committing.
You should, but confirm this in writing before signing. Most reputable agencies transfer full IP ownership to the client on final payment. Some retain IP until the invoice is settled; others use open-source frameworks where ownership is split between the framework licence and your bespoke code. Get this confirmed in the contract and ask for repository access from day one of development.
Look for relevant portfolio work (similar project type and industry), a structured discovery process before they quote a fixed price, clear post-launch support terms, and willingness to give you access to the code repository during development. Ask for two references willing to take a call. Avoid agencies that quote fixed prices from vague briefs without discovery - that number will change.
We protect the real names of all clients featured in examples and case studies. Every testimonial is from a real client.
More from the blog
Work with us
Book a free 30-minute discovery call with DD and get a personalised automation roadmap.
Softomate Solutions Limited
Deen Dayal Yadav
Online
We use essential cookies to keep the site running. With your permission, we also use analytics cookies to understand how visitors use our site so we can improve it. No data is sold. Privacy Policy
