César Siancas, Developer in Bangkok, Thailand
César is available for hire
Hire César

César Siancas

Bio

César has 14+ years of WordPress experience and has worked exclusively through Toptal since 2018. He specializes in custom themes, plugin development, WooCommerce, performance optimization, and API integrations, and has recently delivered 50%+ speed gains and custom ERP integrations for eCommerce clients. César believes proactive communication is the foundation of every successful project.

Portfolio

Mellow Fellow Fun LLC
WordPress, PHP, WordPress Themes, CSS, Advanced Custom Fields (ACF), ACF PRO...
Keystroke Learning
Plugin Development, WordPress, WooCommerce, WordPress Plugins, ACF PRO, PHP...
FreezerFit LLC
HTML, JavaScript, PHP, CSS, WordPress, MemberPress, BuddyPress, eCommerce...

Experience

  • PHP - 9 years
  • PSD to WordPress - 9 years
  • WordPress - 9 years
  • WordPress Themes - 9 years
  • Responsive Web Design (RWD) - 8 years
  • WordPress Plugins - 7 years
  • WooCommerce - 6 years
  • WordPress REST API - 4 years

Preferred Environment

Tower, MacOS, NeoVim Text Editor, Local by Flywheel, Figma, WP-CLI, GitHub, Claude, MySQL, Laravel

The most amazing...

...project I've worked on was a platform that connects professionals across different areas with entrepreneurs who need their specific skill set and advice.

Work Experience

Senior WordPress Developer for eCommerce

2025 - 2026
Mellow Fellow Fun LLC
  • Managed and optimized a portfolio of five WordPress eCommerce websites, with primary ownership of the main revenue-generating platform.
  • Increased website performance by 50%+ by refactoring legacy code, optimizing assets, and implementing a modern SAGE-based architecture.
  • Spearheaded the end-to-end modernization of a legacy website, improving code maintainability and enabling faster feature development.
  • Engineered custom API integrations with ACUMATICA ERP, streamlining data flows and significantly reducing manual intervention.
  • Delivered high-quality, responsive landing pages to support ongoing marketing campaigns and rapid content deployment.
Technologies: WordPress, PHP, WordPress Themes, CSS, Advanced Custom Fields (ACF), ACF PRO, Sage, MySQL, REST APIs, APIs, WordPress Theme Customization

Senior WordPress and WooCommerce Developer

2025 - 2025
Keystroke Learning
  • Refactored the client’s custom plugin to improve scalability and maintainability, cleaning legacy code, optimizing performance, and restructuring components to support future growth and stability.
  • Developed custom WooCommerce integrations to sell courses with multiple dates and formats (online and in-person), enabling flexible product and schedule management within the eCommerce platform.
  • Improved site performance by optimizing load times and responsiveness, while handling ongoing maintenance to ensure stability, compatibility, and smooth platform operation.
Technologies: Plugin Development, WordPress, WooCommerce, WordPress Plugins, ACF PRO, PHP, JavaScript, eCommerce, Back-end Development, Coding, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Developer

2024 - 2025
FreezerFit LLC
  • Implemented BuddyPress integration into the existing website, enabling social and community features while ensuring compatibility with the current WordPress setup.
  • Identified and resolved bugs across the system while implementing incremental improvements to enhance stability, functionality, and overall user experience.
  • Applied design updates to improve UI consistency and usability, along with ongoing maintenance to ensure site stability and performance.
Technologies: HTML, JavaScript, PHP, CSS, WordPress, MemberPress, BuddyPress, eCommerce, Back-end Development, Coding, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Developer

2024 - 2024
TGH B.V.
  • Resolved issues with WP All Import and successfully handled the import of 50,000+ records into custom post types and fields, ensuring data integrity and correct mapping throughout the process.
  • Installed and configured a business directory plugin and ensured proper integration with the import workflow, allowing accurate and automated population of directory data.
  • Optimized theme and plugin code to improve site and back-end performance, addressing issues with large data handling and reducing overall processing bottlenecks.
Technologies: WordPress, WP All Import, User Interface (UI), Back-end Development, Coding, Front-end Development, Full-stack Development, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Website Developer

2023 - 2024
LaGrande Marketing, LLC
  • Handled all aspects of WordPress development, including custom theme creation, ongoing maintenance, and performance optimizations to improve site speed and stability.
  • Built websites using Beaver Builder, developing custom modules when required to extend functionality and meet specific client requirements.
  • Led technical SEO improvements, along with site speed optimizations and general maintenance to enhance visibility, performance, and overall user experience.
Technologies: WordPress, Beaver Builder, Content Marketing Platforms, WordPress Plugins, WordPress Themes, WordPress Design, User Interface (UI), Front-end Development, Full-stack Development, Web Development, Web Technologies, Websites, WordPress Theme Customization

Senior WordPress Developer

2022 - 2023
TestGorilla B.V.
  • Updated the existing WordPress theme and custom plugin to support multiple languages, ensuring proper structure, compatibility, and seamless content localization across the site.
  • Developed custom scripts to improve technical SEO, site performance, and system monitoring, helping identify issues faster and optimize overall site behavior.
  • Automated parts of the translation workflow using XLIFF files and stabilized the deployment process across multiple environments, improving efficiency and reducing release issues.
Technologies: PHP, WordPress, Multilingual Websites, Corporate Websites, JavaScript, Databases, Performance Tuning, APIs, CSS, HTML, Plugins, Themes, Full-stack, User Interface (UI), Back-end Development, Coding, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Senior Developer

2022 - 2022
Orderly Health
  • Developed the client's new main website using the plugin Beaver Builder.
  • Created custom modules for Beaver Builder to provide easy-to-use and reusable elements for the client to use or update in the future on the site.
  • Was in charge of coordinating and implementing the connection between the client's contact forms to the Salesforce service.
Technologies: Figma, WordPress, Content Marketing Platforms, Beaver Builder, PHP, CSS, JavaScript, HTML, WordPress Themes, WordPress Plugins, User Interface (UI), Back-end Development, Coding, Front-end Development, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Developer

2018 - 2022
LaGrande Marketing
  • Led the technical SEO optimizations, speed improvements, and maintenance.
  • Handled everything related to WordPress, from theme creation to general maintenance and speed improvements.
  • Built sites using Beaver Builder and custom module creations for this theme.
Technologies: CSS, Front-end, Responsive Web Design (RWD), PSD to WordPress, WordPress Themes, WordPress, Figma, Content Marketing Platforms, Beaver Builder, User Interface (UI), Front-end Development, Full-stack Development, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Developer

2021 - 2021
Pocketmade
  • Took charge of maintaining and extending their custom WordPress theme and plugins that interacted with marketing and call center external services.
  • Set up and tested GTM and Google Analytics for the many requirements their client has.
  • Handled the integrations between their client site with the LeadConduit platform via an API.
  • Managed the integration between different flows in LeadConduit with the external service BlueShift.
  • Created different Zappier integrations in order to connect their different lead sources with LeadConduit, a real-time lead optimization platform that empowers you to take action on your leads by customizing lead flow.
Technologies: Advanced Custom Fields (ACF), WordPress, PHP, HTML, JavaScript, Google Tag Manager, Google Analytics, GitHub, APIs, Zapier, API Integration, User Interface (UI), Back-end Development, Coding, Front-end Development, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

WordPress Developer

2021 - 2021
Praxent (via Toptal)
  • Fixed SEO-related technical problems for better performance.
  • Owned the creation of Gutenberg blocks since the client was moving aways from the WPBakery builder.
  • Spearheaded the general maintenance and improvements on the site.
  • Improved the current theme structure setting the path for a Gutenberg-based site.
Technologies: Advanced Custom Fields (ACF), WordPress, Gutenberg Editor, Front-end, Back-end, User Interface (UI), Front-end Development, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

Technical WordPress Developer

2020 - 2021
Bridgecrew (via Toptal)
  • Developed the new theme from scratch. This was a responsive theme that used the Tonik starter theme as a basis along with AFC blocks for customization.
  • Owned the general maintenance of the site as part of my role.
  • Fixed bugs and created custom required functionality.
Technologies: Advanced Custom Fields (ACF), WordPress Themes, WordPress Plugins, WordPress, PHP, CSS, HTML, User Interface (UI), Front-end Development, Full-stack Development, Programming, Web Development, Web Technologies, Websites, WordPress Theme Customization

Senior WordPress Developer

2020 - 2020
The Dancel Group, Inc (via Toptal)
  • Developed a custom-made plugin in charge of scheduling publications shared on social media, which also included an import process of all their data.
  • Created a plugin that integrates with WooCommerce and their subscription plugin.
  • Built a custom WordPress theme from scratch using ACF for the back-end.
Technologies: WordPress, PHP, CSS, HTML, JavaScript, Advanced Custom Fields (ACF), API Integration, Facebook API, User Interface (UI), Coding, Front-end Development, Full-stack Development, Programming, Web Development, Web Technologies, Websites

Senior WordPress Developer

2020 - 2020
RoshReview (via Toptal)
  • Owned the creation of the new multisite environment, including the preparation and organization of their current website into different child sites.
  • Created the main WordPress theme for the principal site using Tailwind CSS as our base and Tonik, Starter Theme.
  • Reviewed child themes and updated the files to accomplish better performance.
  • Conducted technical SEO maintenance and improvements to achieve the company's goals.
Technologies: Back-end, Front-end, Page Speed Optimization, Tailwind CSS, WordPress Multisite, WordPress, Advanced Custom Fields (ACF), Figma, User Interface (UI), Front-end Development, Full-stack Development, Web Development, Web Technologies, Websites, Canva

Expert WordPress Theme Developer

2020 - 2020
LyraThemes (via Toptal)
  • Oversaw and was in charge of creating custom themes that adhered to WordPress development standards.
  • Developed a custom plugin using object-oriented programming.
  • Maintained and fixed bugs in WordPress themes and plugins.
Technologies: PHP, CSS, HTML, WordPress, User Interface (UI), Front-end Development, Web Development, Web Technologies, Websites

WooCommerce Developer

2020 - 2020
GAMING DOT ME LLC (via Toptal)
  • Created a plugin that connects with a license number provider to be distributed with WooCommerce.
  • Integrated a custom-made license generator with WooCommerce.
  • Created the necessary back-end administration panel to handle all the information related to licenses.
Technologies: WordPress Plugins, REST, APIs, WordPress, API Integration, Web Development, Web Technologies

WordPress Engineer for Plugin Development

2020 - 2020
Benzinga (via Toptal)
  • Integrated a plugin with the Dictionary.com API.
Technologies: PHP, WordPress Plugins, REST, APIs, WordPress, Web Technologies

WordPress Expert

2019 - 2020
Constructor.io Corporation (via Toptal)
  • Maintained WordPress websites including theme updates using ACF.
  • Created Zendesk themes.
  • Performed quality assurance as needed.
Technologies: Front-end, Responsive Web Design (RWD), PSD to WordPress, WordPress Themes, Zendesk, Advanced Custom Fields (ACF), WordPress

WordPress Developer

2019 - 2020
LazerPro (via Toptal)
  • Oversaw the general maintenance, plugin creation, and migration of their news and listing site from their old non-WordPress platform to WordPress.
Technologies: WooCommerce, WP Engine, WordPress

Back-end WordPress Developer

2019 - 2019
XLR8R Media, Inc. (via Toptal)
  • Headed the entire migration from the Tempest platform to a WordPress one.
  • Created a plugin that integrated Bandcamp subscribers with WordPress.
  • Took charge of the general maintenance of their site.
Technologies: PHP, WordPress Plugins, WP Engine, WordPress

WordPress Expert

2019 - 2019
The Chempetitive Group, LLC. dba CG Life (via Toptal)
  • Developed a responsive WordPress theme from scratch.
  • Played a vital role in the general optimization of the site.
  • Was in charge of handling the maintenance of the site.
Technologies: WordPress

WordPress Developer

2018 - 2019
RoshReview (via Toptal)
  • Improved the overall site speed for better engagement with potential clients.
  • Developed new WordPress themes according to new requirements, using ACF, Gutenberg, and API integration.
  • Took charge of the general maintenance and bug fixing of their current platform.
Technologies: Front-end, Responsive Web Design (RWD), PSD to WordPress, WordPress Themes, WooCommerce, WordPress

Senior Coder

2017 - 2019
Jalador.com
  • Developed an entire WordPress theme from scratch; it was responsive and was built following the recommended speed improvements.
  • Designed a plugin that created all the necessary elements in the backend to make their reservation system work.
  • Built a plugin using WordPress REST API to allow the interaction between their mobile app and their backend.
  • Added more functionality constantly and built custom reports.
Technologies: PHP, CSS, Front-end, WordPress Themes, Sass, WordPress, JavaScript, HTML

Senior Coder

2017 - 2017
M4Agency
  • Developed WordPress themes and plugins for different clients.
  • Implemented the image-to-layout workflow (PSD-to-theme conversion or similar).
  • Converted the old, static website to a WordPress site for Flordecana.com.
  • Maintained the websites for Republicofhumanity.org and M4angency.com.
Technologies: PHP, CSS, Front-end, Responsive Web Design (RWD), WordPress Themes, WooCommerce, JavaScript, Sass, WordPress

Senior Coder

2012 - 2016
Mabbly
  • Developed the WordPress themes and plugins for a variety of clients.
  • Maintained and extended the WordPress sites for multiple clients.
  • Introduced the image-to-layout workflow, including PSD-to-theme conversion.
  • Implemented speed improvements in WordPress sites for different clients to make them follow Google's speed standards, accomplishing an average of. three seconds on different speed test sites.
  • Developed the WordPress theme for a variety of websites, including Drinkkoia.com, Iconid.com, Thegarage.northwestern.edu, Briahs.com, Precisionsoftware.com, and Nationalvanlines.com.
  • Built the WordPress theme, completed the API integration with their system, and improved site speed for Prohabits.com.
  • Integrated API with the NeonCRM and developed a WordPress theme for Smallbusinessadvocacycouncil.org.
  • Created a PHP system using the Kohana framework for Advisor.tv.
Technologies: PHP, CSS, Front-end, WordPress Themes, WooCommerce, Sass, WordPress, JavaScript, HTML

Programmer Analyst

2008 - 2010
Hidrandina S.A.
  • Implemented the client management module, interviewed users, and migrated data from the old system.
  • Led the analysis and development of the cuts and reconnections module.
  • Collaborated with the quality control team to create new versions of the quality control module for their new system.
Technologies: C#, .NET, SQL

Experience

AdvisorTV

An entrepreneurial platform that allows professionals to have a space to display themselves and their knowledge through videos.

I was in charge of creation from scratch, including the front end and back end, along with the general maintenance.

ProHabits

https://prohabits.com
I handled the development of this theme, as well as the plugins that integrated with their system. My work also included ensuring the site was optimized to have a good rank on the main website speed tests.

Jalador.pe

I co-founded this startup, which consists of a platform that allows business owners to obtain clients through customized offers. The entire back end is built in WordPress, and I used a REST API to connect the data and logic with a React application.

Education

2002 - 2007

Bachelor's Degree in Computer and Information Science

National University Pedro Ruiz Gallo - Lambayeque, Peru

Skills

Libraries/APIs

Facebook API, REST APIs, WordPress REST API, WordPress API, Google Maps API, jQuery, BuddyPress, Sage

Tools

Coda 2, MySQL Workbench, PhpMyAdmin, MAMP, Tower, Git, Avocode, Zeplin, Advanced Custom Fields (ACF), Coda, Gulp, Grunt, Terminal, GitHub, Gutenberg Editor, Google Analytics, Zapier, Figma, WP All Import, ACF PRO, Local by Flywheel, WP-CLI, Claude, Canva

Platforms

WordPress, WooCommerce, OS X, Zendesk, MacOS

Languages

CSS, HTML, PHP, Sass, Less, JavaScript, SQL

Paradigms

Responsive Web Design (RWD), REST, Object-oriented Programming (OOP)

Storage

MySQL, JSON, WP Engine, Databases

Frameworks

Tailwind CSS, Laravel

Other

Freelancing, HTML to WordPress, WordPress Themes, PSD to WordPress, PSD to HTML, WordPress Theme Customization, CodeKit, Transmit, WordPress Plugins, Ajax, APIs, Back-end, Front-end, Gravity Forms, Full-stack, API Integration, User Interface (UI), Elementor, eCommerce, Back-end Development, Coding, Front-end Development, Full-stack Development, Programming, Web Development, Web Technologies, Websites, Page Speed Optimization, WordPress Multisite, Google Tag Manager, Beaver Builder, Security, Content Marketing Platforms, Multilingual Websites, Corporate Websites, Performance Tuning, Plugins, Themes, WordPress Design, MemberPress, Plugin Development, NeoVim Text Editor

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.

1

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring