Sarah is available for hire
Hire SarahSarah Audina
Verified Expert in Engineering
Full-stack Developer
Jakarta, Indonesia
Toptal member since June 13, 2022
Bio
Sarah is a full-stack developer with extensive experience in mobile application development and web development. She uses industry standards and loves to experiment with cutting-edge technology in her work. Sarah employs best practices and writes clean code to keep her workflow efficient.
Portfolio
Ailene Menendez Santana
JavaScript, Mobile App Development, Node.js, PostgreSQL 9, WebRTC, OAuth...
New Domain Enterprise
Amazon Web Services (AWS), Go, Elasticsearch, Redis, PostgreSQL...
Unfollowing
Flutter, iOS, Mobile, Android, FlutterFlow, Firebase, Supabase...
Experience
- Firebase - 7 years
- Flutter - 5 years
- JavaScript - 4 years
- Java - 4 years
- Android SDK - 4 years
- React - 4 years
- Node.js - 4 years
- Kotlin - 3 years
Preferred Environment
IntelliJ IDEA, Amazon Web Services (AWS), Firebase, Stripe, iOS, JavaScript, Android Studio, GraphQL, REST
The most amazing...
...thing I've developed is a screen recording application for Android, implemented with Open Graphics Library (OpenGL) to maximize performance.
Work Experience
Full-stack Mobile App Developer
2025 - PRESENT
Ailene Menendez Santana
- Architected and developed a dating application with a customized recommendation system.
- Designed and implemented a recommendation system that effectively addresses cold-start challenges, leveraging research-driven parameter optimization to improve early-stage recommendation accuracy for new users.
- Designed and implemented a responsive dating coach chatbot leveraging CrewAI for agent orchestration, Mem0 for conversation persistence, and Amazon Bedrock for hosting.
- Integrated internal knowledge sources with agents in CrewAI under rule-based guardrails.
Technologies: JavaScript, Mobile App Development, Node.js, PostgreSQL 9, WebRTC, OAuth, OpenAI API, Dating Apps, Stripe API, CrewAI, Mem0, Amazon Bedrock AgentCore, Amazon DynamoDB, Flutter, Dart, Classifier Development, Artificial Intelligence (AI), DevOps, App Store, Xcode, Chatbots, AI Chatbots, Amazon Web Services (AWS), Site Reliability Engineering (SRE), Cloud Architecture, Full-stack Development
Lead Developer
2024 - PRESENT
New Domain Enterprise
- Architected radio player application by leveraging REST API on AWS infrastructure.
- Managed a team of developers, bridging communication between shareholders and the development team.
- Developed back-end application features, including creating a radio scheduler and a radio listening API.
- Developed mobile application features, including creating a radio screen with complex and continuous animation, and improved user experience by optimizing the app performance and removing bottlenecks.
Technologies: Amazon Web Services (AWS), Go, Elasticsearch, Redis, PostgreSQL, Amazon S3 (AWS S3), Flutter, GitHub, Mobile App Development, Mobile Development, Firebase, iOS, Auth0, Fintech, Dart, DevOps, App Store, Xcode, Audio, Swift, Site Reliability Engineering (SRE), Cloud Architecture, Full-stack Development
FlutterFlow Developer
2026 - 2026
Unfollowing
- Reviewed, audited, and improved existing workflow by moving dependency on 3rd-party mailing and marketing libraries.
- Designed and developed features that allow better management of the product, based on the existing database design.
- Resolved bugs, expanded feature functionality, and improved overall usability.
Technologies: Flutter, iOS, Mobile, Android, FlutterFlow, Firebase, Supabase, Full-stack Development
Full-stack Developer
2026 - 2026
UNYOP
- Designed the system and developed an app that tracks flights in real time.
- Designed and developed the system to synchronize data with the ADS-B API.
- Developed a cross-platform mobile application leveraging native functionalities and refined the UI beyond the initial mockups.
Technologies: Swift, Kotlin, React Native, Node.js, Firebase, Google Cloud Platform (GCP), Tailwind CSS, Site Reliability Engineering (SRE), Cloud Architecture, Full-stack Development
Software Developer
2024 - 2024
We Code Craft
- Architected a chatbot plugin that serves visitors to a pediatric clinic website.
- Implemented back-end application in Python, integrating OpenAPI to create an AI assistant.
- Implemented the front-end plugin interface that can be attached to multiple sites, including WordPress and Webflow sites.
- Fine-tuned the AI chatbot to serve the visitors and act as a clinic assistant to improve user experience and ease the onboarding and scheduling process.
Technologies: React, HTML, CSS, Python, OpenAI, OpenAI API, JavaScript, Chatbots, AI Chatbots, WordPress Plugins, Webflow, React Native, DevOps, App Store, Xcode, Tailwind CSS, Next.js
Flutter Mobile Developer
2024 - 2024
My Dream Roadtrip
- Architected the infrastructure and deployed the back-end application in the Firebase environment.
- Developed a backend application that synchronizes the app database with the data from third-party API.
- Developed mobile application features, including an interactive UI with a graph system that synchronized with a map.
Technologies: Flutter, Mobile, Google Maps, Firebase, Node.js, Express.io, TypeScript, Tree Structures, Graphs, iOS, OpenStreetMap, Cloud Run, App Store, Apple Pay, Stripe, Google Cloud Platform (GCP), Mobile App Development, Mobile Development, JavaScript, NPM, Auth0, Fintech, Dart, DevOps, Xcode, Full-stack Development
Founding Software Developer
2023 - 2024
MemoryLane
- Revamped the Flutter codebase to enhance efficiency, reduce bugs, and significantly expedite development cycles, enabling quick iteration for idea validation.
- Set up CI/CD, reducing deployment time from 2 hours to 30 minutes.
- Managed app releases on the App Store and Google Play, ensuring strict compliance with their guidelines. This effort contributed to the successful launch and initial product sales.
- Collaborated with another developer to optimize API performance in the Firebase environment with cost efficiency in mind.
Technologies: Flutter, Node.js, Firebase, Android, Google Play Store, App Store, Google Cloud Platform (GCP), DevOps, Artificial Intelligence (AI), APIs, Full-stack, Stripe, JavaScript, React, Mobile App Development, iOS, Mobile Development, TypeScript, OpenAI, NPM, Auth0, Fintech, Dart, Xcode, Audio, Cloud Architecture, Full-stack Development
Android Developer
2023 - 2023
Kixieweb Inc
- Upgraded the application's support libraries, increasing the potential market by 100% compared to the previous version.
- Fixed critical bugs in the sales engagement platform's Android app.
- Oversaw the launch process, processed feedback, and advised on problems that hindered the launch process.
Technologies: Android, Kotlin, Android SDK, Java, Mobile App Development, Mobile Development
Flutter Developer
2022 - 2023
Lantern Pharma Inc.
- Architected and developed promotional applications for a clinical trial for a cancer treatment, from scratch to production.
- Leveraged the powerful combination of Flutter and Firebase to expedite development while significantly reducing project costs.
- Oversaw the medical apps' releases to the App Store and ensured compliance with HIPAA and App Store guidelines.
Technologies: iOS, Flutter, Firebase, Mobile Apps, Node.js, Google Cloud Platform (GCP), Mobile Development, JavaScript, TypeScript, NPM, Dart, Xcode, Swift
Mobile Developer
2022 - 2022
Freelance
- Developed a voice-based messaging application for Android and iOS in a Flutter codebase.
- Gathered requirements from clients and translated them into tasks.
- Implemented a complex UI that involved heavy animations and graphs.
- Executed code review and testing and built testing versions using automation tools.
Technologies: Flutter, Dart, Node.js, Reactive Programming, Mobile Apps, Google Cloud Platform (GCP), React, React Native, Mobile Development, JavaScript, TypeScript, NPM, Firebase, iOS, Kotlin, Tailwind CSS
Android Engineer
2021 - 2021
Freelance
- Contributed to a core video editing library by maintaining the existing code, troubleshooting, and fixing bugs.
- Helped analyze performance enhancement strategies.
- Adjusted demo application UI to new design requirements.
Technologies: Android SDK, FFmpeg, Mobile Apps, OpenGL, Google Cloud Platform (GCP), Mobile Development, JavaScript, TypeScript, Dart, Kotlin, NestJS
Full-stack Developer
2021 - 2021
Freelance
- Developed a web-based CMS to improve the existing one's features by customizing a Blade template and implementing supporting API for a 2nd-hand electronics marketplace.
- Gathered and translated client requirements into a detailed task for the team to execute.
- Architected the CMS and MySQL database with a back-end specialist.
- Implemented the API in Laravel and customized the Blade template while coordinating with a back-end specialist.
- Reviewed and tested the code and deployed the CMS into the hosting site.
Technologies: HTML, CSS, MySQL, Heroku, Full-stack, APIs, MongoDB, Node.js, React, Google Cloud Platform (GCP), Mobile Development, JavaScript, TypeScript, Web, Dart, Kotlin, Audio
Mobile Engineer
2018 - 2020
TLab
- Set up the Flutter codebase and developed and maintained a lifestyle application for Android and iOS, reaching over 500,000 downloads.
- Tracked and fixed bugs using Airtable as a reporting tool.
- Maintained the Flutter codebase and improved performance, resulting in a high user rating.
- Deployed and took charge of Android versioning in the Google Play store.
Technologies: Google Play Store, Flutter, Firebase, Android SDK, Java, SQLite, Mobile Apps, Node.js, Google Cloud Platform (GCP), iOS, Mobile Development, JavaScript, TypeScript, Auth0, Dart, Kotlin, Swift, NestJS
Experience
AI-based Virtual Assistant Price Estimator
A web application that estimates price cards for virtual assistants to be hired for specific roles.
I implemented the app using ChatGPT to classify the input into defined categories. I also used Node.js to build the app and React for the UI.
I implemented the app using ChatGPT to classify the input into defined categories. I also used Node.js to build the app and React for the UI.
Medical Chatbot
https://demo-2-dbdb15.webflow.ioA medical chatbot designed to be easily attached to websites.
On the back end is a Python application integrated with OpenAI API using OpenAI assistant. Short-term memory management was implemented to ensure a coherent conversation with the AI assistant.
On the back end is a Python application integrated with OpenAI API using OpenAI assistant. Short-term memory management was implemented to ensure a coherent conversation with the AI assistant.
Education
2013 - 2018
Bachelor's Degree in Electronics and Instrumentation
Gadjah Mada University - Yogyakarta, Indonesia
Certifications
OCTOBER 2022 - OCTOBER 2025
AWS Certified Developer Associate
Amazon Web Services
APRIL 2022 - PRESENT
Binar Academy Bootcamp Business Intelligence Analyst
Binar Academy
Skills
Libraries/APIs
Node.js, FFmpeg, OpenGL, Stripe, React, Google Maps, OpenAI API, WebRTC, Stripe API
Tools
Android Studio, Auth0, NPM, IntelliJ IDEA, Xcode, GitHub
Frameworks
Flutter, Android SDK, Next.js, Tailwind CSS, NestJS, Hapi.js, WebApp, Express.io, React Native, Mem0
Paradigms
Mobile Development, REST, Reactive Programming, Business Intelligence (BI), DevOps
Platforms
Firebase, iOS, Android, Google Cloud Platform (GCP), Heroku, Web, Visual Studio Code (VS Code), Amazon Web Services (AWS), Mobile, Cloud Run, Webflow, CrewAI, FlutterFlow
Languages
Kotlin, Dart, CSS, JavaScript, HTML, Java, TypeScript, GraphQL, Go, Python, Swift
Storage
MongoDB, SQLite, MySQL, Elasticsearch, PostgreSQL, Redis, Amazon S3 (AWS S3), Amazon DynamoDB
Other
Mobile App Development, Audio, Full-stack Development, Supabase, Mobile Apps, OpenAI, Fintech, Cloud Architecture, Site Reliability Engineering (SRE), Data Analysis, Google Data Studio, Google Play Store, Serverless, App Store, Artificial Intelligence (AI), Full-stack, APIs, Web Development, Classifier Development, Tree Structures, Graphs, OpenStreetMap, Apple Pay, Chatbots, AI Chatbots, WordPress Plugins, PostgreSQL 9, OAuth, Dating Apps, Amazon Bedrock AgentCore
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