Custom Theme Agency
Your BigCommerce theme should drive revenue, not hold it back
Generic themes limit what your brand can do. A custom BigCommerce Stencil theme gives you full control over every template, every component, and every conversion moment.
Submit brief → design consultation within 48 hours → scoped proposal in 3 days → Sprint 1 within 1 week of sign-off
0%
Revenue growth on custom BigCommerce builds
0/100
Average PageSpeed after Stencil optimization
0weeks
Typical delivery timeline for custom themes
0%
App Marketplace compatibility on all builds
The real cost of a generic theme
Most theme projects fail before the first pixel ships
When design intent and development scope are blurred from the start, you get a theme that looks like a template and performs like one too.
What you get with a separated implementation path
Design-to-Stencil handoff with fidelity tracking
Each design decision maps to a Stencil component or template variable. Nothing is interpreted. Every detail is specified before code starts.
Performance-first Stencil builds
Only the scripts your store uses ship with your theme. Render-blocking assets are removed. Core Web Vitals targets are set before development begins.
Update-safe component architecture
Custom templates extend Cornerstone cleanly. Overrides are isolated. BigCommerce platform updates do not touch your custom layer.
Redesign without replatforming
You can get a fully new visual identity and user experience without migrating data, rebuilding integrations, or re-testing your entire commerce stack.
What you get without a clear implementation path
Design intent gets lost in handoff
Figma files go to a developer who builds what they can, not what was designed. Spacing, type, and micro-interactions disappear.
Off-the-shelf themes ship unused scripts
Marketplace themes load 40 to 80 KB of JavaScript your store never uses. Core Web Vitals suffer. Conversion rates follow.
Customization breaks on every update
Hacked-together overrides create debt. Every BigCommerce platform update risks breaking your checkout, navigation, or product detail page layout.
No separation between redesign and rebuild
Agencies scope redesigns as full platform migrations. You pay for replatforming work you do not need, and go live six months late.
Stencil theme architecture
How we build BigCommerce themes that last
Select any phase to see exactly what happens and why it matters for your storefront.
01
Discovery and Brief
Brand, conversion goals, and scope
02
Wireframe and Design System
Tokens, layouts, and component library
03
Stencil Setup and Templates
Parent extension, page templates, config
04
Component Build
Product detail, listing, cart, checkout, content pages
05
Performance Quality Assurance
Core Web Vitals, device, and browser matrix
06
Deploy and Handoff
Stencil push, docs, and source transfer
Phase 01: Discovery
Every theme starts with a brief, not a mood board
We map your conversion goals, brand guidelines, and technical constraints before a single Figma frame opens. Scope is locked to your required page templates, not expanded mid-build.
Brand Tier
Premium DTC
Parent Theme
Cornerstone 6.x
Page Templates
8 custom
Target LCP
Under 2.5s
Required custom pages
HomeProduct DetailCategoryCartBlogSearchAccount404
Phase 02: Design System
Design tokens first. Pixel-perfect components second.
Color, type, spacing, and motion are defined as tokens before component design begins. This means your Stencil SCSS variables match Figma from day one.
// Brand token output, synced to Stencil
theme.scss
"color":
"brand-primary":"#111517",
"accent":"#923ef2",
"surface":"#f5f5f7"
// 42 tokens exported to Stencil variables
Phase 03: Stencil Setup
Cornerstone extended, never hacked
We extend the Cornerstone parent theme using Stencil's official override system. Your custom templates sit in their own directory. Platform updates never conflict with your code.
my-brand-theme/
templates/
components/custom only
pages/8 overrides
assets/
scss/brand.scss
js/theme.js
config.jsontheme settings
parent: [email protected]
Phase 04: Component Build
Every page template built to spec
Product detail, category, cart, search, account, and content pages are built as atomic Stencil components. Each renders cleanly on mobile, tablet, and desktop with no layout shift.
Home Page
Done
Product Detail Page
Done
Category / Listing
Done
Cart and Mini-cart
In review
Search Results
Building
Account Portal
Queued
Phase 05: Performance Quality Assurance
No theme ships without passing Core Web Vitals
Lighthouse runs on every device breakpoint. Accessibility checks cover WCAG 2.1 AA. Browser matrix covers Chrome, Safari, Firefox, and Edge before any theme activates.
LCP Mobile 4G1.9s
Cumulative Layout Shift0.04
Total Blocking Time80ms
Phase 06: Deploy
You own the source code from day one
Theme pushed to your store via Stencil CLI. Full source code, documentation, and a recorded handoff session. You leave with everything needed to maintain or extend independently.
$ stencil bundle
Building production bundle...
Bundle complete: my-brand-theme.zip
$ stencil push --activate
Activating: my-brand-theme v1.0.0
Theme is now live. Store ID: 12847
$
What we deliver
Theme capabilities built for your brand
Custom Stencil builds, performance targets, and safe redesign paths — scoped as three deliverables your team can review before launch.
Custom Stencil development
Built from Cornerstone, designed for your catalog
Every page template reflects your product category and shopping behavior. Product detail layouts vary for single-SKU, variant-heavy, and configurable products. Category pages adapt to your faceted navigation depth.
- Cornerstone parent extension with clean override directories
- Page Builder sections for your merchandising and content team
- Configurable theme settings panel for non-technical brand updates
Premium Brand
$89.00
In stock. Ships today.
Add to cart
DescriptionSpecsReviews (42)
Performance optimization
Themes that score 90 or more before you see them
PageSpeed targets are set in the brief and verified in quality assurance. We remove render-blocking scripts, lazy-load below-fold images, and inline only critical CSS. Your Core Web Vitals improve with your theme, not after it.
- Render-blocking script audit and elimination before build
- Critical CSS inlined, non-critical deferred per Stencil best practice
- CLS-safe image placeholders prevent layout shift on listing page grids
94
Performance Score
First Contentful Paint0.8s
Largest Contentful Paint1.9s
Total Blocking Time80ms
Cumulative Layout Shift0.04
Speed Index1.2s
Redesign without replatforming
New brand identity, same proven commerce engine
Your store data, integrations, and checkout flow stay exactly as they are. We replace only the theme layer. No data migration. No integration re-testing. No downtime risk from a full replatform project.
- Theme previewed on a draft before any live change
- Activation takes under 60 seconds with stencil push
- Instant rollback to previous theme if needed
my-brand-theme v1.0.0
Uploaded 10 min ago
cornerstone-og
Previous active, 6 days ago
Deployment log
14:32 Theme
activated successfully
14:31
Bundle validated, 0 errors
14:29
Push initiated via Stencil CLI
Platform-specific proof
What a custom BigCommerce theme build actually delivers
0%
Revenue growth in 3 years
$3.8M
Annual revenue reached
0
Paid ad spend. Owned channels only.
Client
Off Grid Knives
Outdoor / Premium DTCA premium manufacturer of outdoor and camping knives in a category with strict paid advertising restrictions. Growth had to come from the product and the platform. Not ad spend.
The problem
The existing store setup limited performance, user experience, and order processing. Without paid ads, every visitor arriving organically had to convert. If they left, the brand stalled.
What happened
A custom BigCommerce store was developed with user experience research, Stencil-based performance optimization, and Klaviyo integration. Organic search engine optimization and owned-channel revenue replaced every paid acquisition channel.
Under the hood
Our Stencil theme engine
Select any pipeline stage to see what runs, what we validate, and what you receive. No black-box builds.
• LiveStage 1
stencil init
Scaffold and parent connection
• CompileStage 2
stencil start (local dev)
Hot-reload dev server
• ReviewStage 3
stencil push --draft
Staging preview on live store
• QAStage 4
Lighthouse and device matrix
Performance and accessibility sign-off
• DeployStage 5
stencil push --activate
Live activation with instant rollback
$ stencil init
Which theme would you like to clone?
> Cornerstone
(recommended)
Cloning Cornerstone v6.14.0...
Stencil theme initialized in /my-brand-theme
Created: templates/ scss/ js/ assets/
Ready. Run stencil start to begin local development.
What this means for you
Your theme inherits all Cornerstone templates. We override
only the pages and components in scope. No full rewrites.
No orphaned code.
$ stencil start
Starting local development server...
Proxy: https://store-12847.mybigcommerce.com
Local: http://localhost:3000
Watching for changes...
[HMR] scss/brand.scss updated in 43ms
[HMR] templates/pages/product.html updated in 67ms
What this means for you
Every template change is previewed against your live
catalog and real product data. What you see in development
is what ships.
$ stencil push --draft
Bundling theme assets...
SCSS: 42.3 KB JS: 87.2 KB Templates: 31 files
Draft theme available for preview
What this means for you
You and your team review the full theme on your live store
with real products before any visitor sees a single
change.
$ lighthouse --preset=desktop
Running Lighthouse audit...
94
Perf
98
A11y
100
Best Practices
97
Search
All Core Web Vitals pass. Ready for activation.
What this means for you
No theme activates until it clears our quality assurance
matrix. Performance, accessibility, and cross-browser
coverage are signed off in writing.
$ stencil push --activate
my-brand-theme v1.0.0 is now live
Previous theme: cornerstone-og (saved, restorable)
Handoff package ready:
Source code repository (GitHub invite sent)
Theme documentation PDF
Recorded walkthrough session
What this means for you
You own the code. You can extend it, hand it to another
developer, or bring us back for iterative work. No
lock-in.
Why Redefine
Three things most theme agencies skip
Typical partners blur design intent and development scope. We separate them. Select each claim to see exactly how.
Performance is scoped in, not bolted on
Most agencies build the theme first and optimize afterward. We set Largest Contentful Paint, Cumulative Layout Shift, and First Input Delay targets in the discovery brief, so every component is architected for those scores from the first commit. Quality assurance does not start until the theme passes Lighthouse on mobile.
Typical partner
Performance reviewed after user acceptance testing. Fixes in post.
What we do
Performance targets locked at kickoff. Every sprint reviewed against targets.
Your outcome
Theme activates with 90 or more Lighthouse, not 60 that you chase later.
Redesign and rebuild are separate services
Other agencies scope a visual refresh as a full rebuild. You end up paying for a replatforming project when you needed a new look. We scope redesigns at the theme layer, keep your data and integrations untouched, and activate in under a minute.
What a redesign as rebuild costs
- Data migration risk
- Integration re-testing
- 6-plus month timelines
What a theme-layer redesign delivers
- No data migration
- Integrations stay live
- 6 to 10 week delivery
You receive code, docs, and a real handoff
Most agencies deploy your theme and send a Loom. We deliver full source code on a Git repository, theme documentation covering every custom template and variable, and a live recorded walkthrough session with your team. You are never dependent on us to make changes.
Git repository
Full source with commit history
Theme docs
Every template and variable documented
Recorded walkthrough
Live session for your team
Frequently asked
Theme questions answered
Stencil is the official BigCommerce theming framework. It gives developers full control over templates, styles, and client-side logic without modifying platform core files. Custom Stencil themes allow you to design every page and component to brand specification while keeping full compatibility with BigCommerce updates and the App Marketplace.
Most custom BigCommerce theme projects run 6 to 12 weeks depending on scope. A Stencil customization of a parent theme takes 4 to 6 weeks. A fully bespoke build from wireframe requires 8 to 14 weeks. Timeline depends on the number of unique page templates, component complexity, and quality assurance scope.
Yes. Many projects start from Cornerstone or another Marketplace theme, then extend it with custom templates, overridden styles, and new components. We evaluate whether to extend or build from scratch based on your design goals, performance targets, and long-term roadmap.
Done correctly, a custom Stencil theme improves performance compared to off-the-shelf themes loaded with unused scripts. We audit render-blocking assets, optimize image pipelines, defer non-critical JavaScript, and structure CSS for minimal layout shift. Core Web Vitals targets are built into our quality assurance process before any theme ships.
After launch, your team receives full source code, documentation, and a handoff session. For ongoing optimization, A/B testing, or iterative component work, we offer a growth retainer that keeps your development capacity on-demand without re-scoping each time.
Scope and budget guidance4 to 6 weeks6 to 12 weeks8 to 14 weeks
Which scope fits your store?
Scoped before work starts · line-by-line pricing · no commitment to receive a proposal
Extend
Theme customization
Brand a Cornerstone or Marketplace theme with custom styles, header, footer, and up to 3 template overrides.
Best for: stores that need a new look without full user
experience restructure
Build
Custom Stencil build
Full custom theme from wireframe to deploy. Includes 6 to 8 page templates, component library, config panel, and quality assurance sign-off.
Best for: brands with a design system or specific user
experience requirements
Redesign
Brand refresh
New visual identity applied through Stencil. Includes user experience research, wireframes, design system creation, and full build. No replatforming required.
Best for: established stores ready for a full brand
elevation
Is this the right fit?
Honest about who we build for
Custom theme work is a real investment. We do our best work with teams who know what they need before we scope.
Good fit for...
- Brands with clear design goals and a product catalog that Cornerstone can not handle cleanly
- Stores where Core Web Vitals are underperforming and conversion is suffering as a result
- Teams who want a full visual refresh without the risk and cost of replatforming
- Operators who want to own the source code and documentation after delivery
Not a fit if...
- You need a basic color and logo swap on a Marketplace theme with no custom components
- Your launch timeline requires a live theme in under 3 weeks with no quality assurance phase
- You have no design direction or brand guidelines and need creative strategy alongside development
- You want to migrate to a new platform at the same time as changing your theme
Not sure? Tell us your situation and we will be straight with you. Tell us your situation →
