Web Development Services · St. Petersburg, FL

Web Development Services That Ship Fast and Rank

We are a web development company in St. Petersburg, FL. From a 5-page marketing site to a multi-feature web application — we build on React, Next.js, and Node.js with SEO implemented at build time, not bolted on after launch.

SEO baked into every build
You own the source code
Fixed-price proposals
Bi-weekly demos
Web Project · Active
Live
01Discovery & architecture
DONE
02UI design & prototype
DONE
03Build & QA
LIVE
04SEO & launch
LIVE
05Support & iterate
ONGOING
web application development company React · Next.js · Node.js SEO-ready from first deploy Source code yours from sprint 1 Web development company · St. Petersburg, FL

Web Development Services

The Kind of Websites & Web Apps We Build

From a conversion-focused marketing site to a full web application with auth, dashboards, and third-party integrations — same in-house team, same design system, same handoff-free process.

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🌐

Marketing Websites

Fast, conversion-optimised marketing sites built on Next.js or headless CMS. Technical SEO implemented at code time — schema markup, Core Web Vitals targets, and performance budget all locked before we write a line of CSS. The marketing site and the product UI share the same design system, so your brand never breaks at the login screen.

Next.jsHeadless CMSLanding pagesSEO-readyCRO
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Web Application Development

Dashboards, internal tools, portals, and full-stack web applications. We architect for the real user — the person who will be in this app for six hours a day — with clean data models, fast queries, and a UI that doesn't require a training manual. The web application development process starts with architecture, not Figma.

ReactNode.jsPostgreSQLREST & GraphQL APIsDashboards
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🛒

E-commerce Development

Custom storefronts, headless e-commerce, and product platforms built for performance and conversion. We integrate with Stripe, payment gateways, and inventory systems — and build the paid ads and SEO funnel alongside the store, not months later.

Headless commerceStripeCustom storefrontsProduct catalogueCheckout optimisation
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📄

CMS Development & Integration

Content-managed sites your marketing team can actually use without calling a developer. We build headless CMS setups using Contentful, Sanity, or WordPress — with structured content models, custom blocks, and preview environments. Content editors update pages safely; engineers never get pulled in for a copy change again.

ContentfulSanityWordPress headlessStructured contentPreview environments
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🎨

Web Design & UI UX

We don't just make things look good — we design for the action you want the user to take. Wireframes, interactive prototypes, design systems, and component libraries that development can implement without interpretation. Every design decision is tested against real user flows before a sprint begins.

UI UX designWireframingPrototypingDesign systemsFigmaAccessibility
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What We Build With

Modern Stack. Boring in All the Right Ways.

We don't chase trends. We use the technologies that are proven, well-documented, and that your internal team can maintain after we're done. React, Next.js, and Node.js for web applications. PostgreSQL for data. AWS and Vercel for deployment. All choices driven by your project requirements — not our comfort zone.

Every technology choice gets justified in the architecture document before a line of code ships. If we recommend something unfamiliar to your team, we explain why and provide documentation so you're never locked in to understanding only what we built.

Frontend
React Next.js TypeScript Tailwind CSS Framer Motion
Backend & API
Node.js Python REST APIs GraphQL Supabase
Database & Infra
PostgreSQL AWS Vercel Docker GitHub Actions
CMS & Content
Contentful Sanity WordPress headless Webflow

What You Actually Get

Web Development Done Right Means This

Not just a website. A production-grade platform your team can maintain, your marketing team can update, and your customers can trust.

SEO implemented at build time

Schema markup, Core Web Vitals targets, canonical tags, sitemap, robots.txt, and internal link architecture — set up during development, not after. Our dev team and SEO team share the same sprint board.

Performance budget enforced

We set a Lighthouse score target before the build starts and hold to it. Lazy loading, image optimisation, font subsetting, and CDN deployment are standard — not extras.

Mobile-first, accessibility-compliant

Every component is built mobile-first. WCAG 2.1 AA accessibility standards are tested throughout, not checked at the end. 58% of web traffic is mobile — it's not an afterthought.

Repos in your org from sprint one

Your code lives in your GitHub organization from the first commit. You are never locked out. If you part ways with us tomorrow, your team can continue without interruption.

What's included — every project
Technical SEO implementationIncluded
Core Web Vitals optimisationIncluded
Mobile-responsive designIncluded
WCAG 2.1 AA accessibilityIncluded
Source code ownershipDay 1
Repos in your GitHub orgSprint 1
Bi-weekly demosEvery project
Fixed-price proposalBefore code starts
Staging environmentIncluded
Post-launch supportOptional retainer
SEO content strategyAdd-on
Paid ads campaignsAdd-on

How We Work

From Brief to Live Site in 4 Phases

No black boxes. Fixed-price proposals, bi-weekly demos, and a clear handoff at the end of every phase. The same rhythm for a 5-page site or a full web application.

01

Discover & Plan

We workshop your requirements, map user journeys, lock the scope, and produce a fixed-price proposal before a line of code ships.

Product brief
Tech architecture doc
Fixed-price proposal
02

Design & Prototype

Wireframes, interactive Figma prototypes, and a design system. We test with real users where it matters so the build phase isn't full of redesign requests.

Figma prototype
Design system
User journey maps
03

Build & QA

Sprint-based development with bi-weekly demos. You see working software every two weeks — not status updates. QA runs in parallel throughout.

Bi-weekly demos
Staging environment
Repos in your org
04

Launch & Support

Cloud deployment, SEO go-live, and optional paid + organic campaigns flip on simultaneously. Post-launch SLA and WhatsApp support stay on as long as you need.

Production deploy
SEO live
Support SLA

Industries We've Built For

Web Development for Your Industry

Different compliance requirements, different user expectations, different conversion flows. We've shipped across all of these.

🏥

Healthcare

Patient portals, telehealth platforms, and clinical tools — HIPAA-compliant architecture from day one, not bolted on for review.

☁️

SaaS & B2B

Web application development for SaaS products — dashboards, onboarding flows, billing, and multi-tenant architecture.

🛒

E-commerce & D2C

Headless storefronts, product catalogues, and checkout flows optimised for conversion and mobile performance.

🏢

Real Estate

Listing platforms, agent CRMs, and lead-gen sites with local SEO baked in — built to generate enquiries, not just look good.

💳

Fintech

Compliance-first web applications — KYC flows, dashboards, and customer portals with bank-grade security architecture.

💪

Fitness & Wellness

Membership platforms, booking systems, and coach portals — built for engagement and built to convert free users into paying members.

Said About Us

What Clients Actually Say

★★★★★
"They delivered the marketing site and the web application on the same design system — our brand is consistent right through to the dashboard. First dev agency that ever made that happen without us having to ask."
JM
James M.
Founder — B2B SaaS
★★★★★
"SEO was live on launch day, not three months later. The site hit page one for our primary keyword in under 90 days. That's what happens when the dev team and the SEO team share the same sprint board."
SR
Sara R.
CMO — Digital Health Startup
★★★★★
"Bi-weekly demos meant we were never surprised. Every two weeks we saw working software — not status reports. The final launch was boring in the best way. Nothing unexpected."
DK
David K.
CTO — E-commerce Platform

FAQ

Web Development Questions

The things buyers ask us in the first week — from timelines and tech choices to ownership and post-launch support.

Ask Us Directly →

A marketing website typically takes 4–6 weeks from signed brief to launch. A full web application or dashboard takes 8–16 weeks. Complex multi-feature platforms with third-party integrations run 3–6 months. Every project starts with a fixed scope and fixed-price proposal before development begins — no vague timelines.

We build primarily with React and Next.js for web applications, with Node.js on the backend. For content-driven sites we use headless CMS setups — Contentful, Sanity, or WordPress headless depending on your team's needs. PostgreSQL for databases. AWS and Vercel for deployment. Every technology choice is documented and justified so you understand what you're running and why.

Yes. Technical SEO is implemented during development — not retrofitted after launch when it costs 3× more. Schema markup, Core Web Vitals optimisation, canonical tags, XML sitemap, robots.txt, internal link architecture, and performance budget are all handled at build time. Our development team and SEO team share the same sprint board.

Yes — we cover the full spectrum. From a 5-page marketing site to a complex multi-tenant web application with auth, role management, dashboards, APIs, and third-party integrations. The same in-house team handles both, on the same design system, so the brand never breaks at the login screen.

You do. Full source code ownership is in every contract. Repositories live in your GitHub organization from sprint one — not transferred at the end. If you part ways with us tomorrow, your team can continue without interruption. We are never the single point of failure for your product.

Yes. We offer post-launch support retainers covering bug fixes, security updates, performance monitoring, feature additions, and a WhatsApp line for urgent issues. Retainers are flexible — scale up for a launch period, scale back during quiet months. No annual lock-in.

Web design is the visual and UX layer — wireframes, prototypes, visual design, component systems, and user flows. Web development is the engineering layer — turning designs into working code with data, logic, performance, and infrastructure. We handle both in-house, so there's no brief-lost-in-translation between a designer at one agency and a developer at another.

Web application development is the process of building interactive, data-driven software that runs in a browser. Unlike a standard marketing website, a web application typically includes user authentication, a database, business logic, API integrations, and real-time data updates. Examples include SaaS dashboards, internal tools, customer portals, and e-commerce platforms with custom checkout flows.

Start a Web Project

Tell Us What You're Building

We'll come back with a clear scope, timeline, and fixed-price proposal. No commitment needed to get a quote, and we sign an NDA before anything sensitive is shared.

Fixed-price proposal before development starts
NDA signed before kickoff
Response within 24 hours
You own the code from day one

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Or email: Contact@siznex.com · +1 (437) 254-2512

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