Home / Single Page App Developer, Cape Town
A Cape Town developer for one focused app on your website, not a platform.
It sits on a page of the site you already have, talks to your systems through an API, and updates without reloading the page. Eight free tools prove the shape.
Does this sound like you?
- “We’re on WordPress or Shopify already, and just need one more screen, not a new platform.”
- “Our off-the-shelf tool does most of what we need, but the last bit that matters, it can’t do.”
- “The spreadsheet has grown so important that nobody dares touch it anymore.”
- “A previous developer disappeared, and took the code with them.”
What I’d do.
Tell me about the tool in two sentences.
I’ll say up front whether it’s browser-only, connected to your systems, or built inside your existing site.
Build the smallest useful version first.
Working on your own examples, not a mockup, before anything else gets added.
Hand it over with a plain runbook, as agreed in the scope.
You always know how it works and who to call.
Proof.
Eight free tools are live at /tools right now: a billing app, a payslip generator, a profit margin calculator, a project estimator and more. All but the compound interest calculator run entirely in your browser, with nothing stored anywhere else. Open one and see the shape before deciding what to build for your own workflow.
A course and product selector with its own database.
Built into WordPress, with a state-driven course selection journey and its own database behind it.
See the ICA selector project →
A parking booking dashboard, still supported three years on.
A real-time dashboard replacing manual airport parking bookings, with automated sync.
See the Storewell dashboard →Excellent effort and work on a tricky project. Clear communication.
Tell me about the tool in two sentences, by email, phone, or WhatsApp.
I review every enquiry personally.
For your technical person
The three shapes
A single page app loads once, then updates in place as the visitor clicks, fetching data from an API in the background instead of reloading the page.
- Browser-only: IndexedDB or localStorage, JSON export, PDF or print output, no backend.
- Connected to your systems: REST, GraphQL, WordPress, WooCommerce, Shopify, CRM and ERP APIs.
- Platform-embedded: shortcode apps inside WordPress, configurators inside Shopify, CRM admin screens.
Client work in production
Optivest price calculator and MedXpert (WordPress, REST API), Storewell parking booking dashboard (WordPress admin, custom REST API), ICA course and product selector (WordPress, React, MySQL, REST API), the Truly Essential Shopify credit system (Shopify, React, Node API, ERP), a VIN lookup app (WordPress plugin, external API), a school lookup app (WordPress, Google Custom Search JSON API), and a find-a-surgeon app (React, PHP APIs, SQL, geolocation and map APIs). Built in React and Next.js since 2017.
Free public tools
Billing app, payslip generator, profit margin calculator, project estimator, email signature generator, payment gateway fee comparator, compound interest calculator, PayPal.Me link generator. All Next.js. All but the compound interest calculator run entirely in your browser, with IndexedDB or localStorage where they need to remember anything.
Specialist terms and job titles
Also described as: single page app developer Cape Town, SPA developer, React developer Cape Town, browser tool developer, embedded WordPress app developer.
Questions owners ask.
Can a tool like this connect to an external system?
Yes. That is one of the three shapes I build. The school lookup app and the VIN lookup app are both shipped examples that read from an outside API.
Can it write data to WordPress, Shopify, or a CRM?
Yes. The MedXpert and ICA selector both write through the WordPress API. The Shopify credit system writes through a Node API into the client ERP. The Storewell dashboard writes through a custom WordPress API.
When does it need a backend?
When more than one person needs to see the same data, when the data has to survive a browser wipe, when the workflow connects to another system, or when the inputs are too long for the browser to be the right place to keep them.
Can you build this in Next.js?
Yes. Browser-only tools are usually plain React or Next.js with the data layer in IndexedDB. API-connected apps use Next.js routes or a separate Node API. Both shapes are in the back catalogue.
Can a tool like this be a public SEO lead magnet?
A useful public tool can attract its own search demand and demonstrate the format, but consulting demand has to be measured separately. The tools at /tools are public examples, not evidence that every tool creates qualified enquiries.
Can it start browser-only and grow later?
Yes. The cheapest path is to start with the smallest useful version and add a backend and accounts when there is a real reason to. The free billing app is the public version of that decision.
Related help.
Open a free tool first, then tell me what your own screen needs to do.
+27 87 150 9305Monday to Friday, 09:00 to 20:00 SAST. Or email info@antondevilliers.com.