Ashim is available for hire
Hire AshimAshim Saha
Verified Expert in Engineering
Full-stack Developer
Deoghar, Jharkhand, India
Toptal member since June 13, 2022
Bio
Ashim is a software developer with nine years of experience. He specializes in using the Flutter toolkit to create mobile applications. He has delivered robust web apps, integrated and unit-tested web services with JavaScript, built tools to increase automation and reduce errors, and worked with cloud platforms and technologies such as AWS, Docker, and Kubernetes. Ashim creates tools that help companies automate and effectively improve their day-to-day performance.
Portfolio
Self-employed
Rust, Flutter, FlutterFlow, Databases, No-code Development, System Design...
Atlan Pte Ltd
Kubernetes, Go, Docker, Keycloak, Apache Ranger, Ranger, PostgreSQL, Back-end...
Freelance
Flutter, Redux, Go, Firebase, Dart, Material UI, ECMAScript (ES6), GraphQL...
Experience
- JavaScript - 8 years
- Software Architecture - 7 years
- SQL - 5 years
- Go - 4 years
- Node.js - 4 years
- Full-stack - 4 years
- Flutter - 3 years
- React - 3 years
Work Experience
Full-stack Mobile Developer
2023 - PRESENT
Self-employed
- Created the mobile UI of the password manager mobile app from scratch using Flutter, FlutterFlow, and Rust.
- Tried to save the data locally in the device and securely. Due to this, I used Rust as the back end. The Flutter app talked to the Rust back end using FFI.
- Used Firebase to sign up and log in and for app monitoring purposes.
Technologies: Rust, Flutter, FlutterFlow, Databases, No-code Development, System Design, Low Code, Supabase
Senior Back-end Engineer
2022 - 2023
Atlan Pte Ltd
- Maintained the existing authentication and authorization services in Go. Also, built new APIs and implemented some of the SSO features.
- Migrated the Keycloak to the latest version and Keycloak SPIs.
- Used to debug several components of the back end to solve issues and maintain the existing codebase, and created new features.
Technologies: Kubernetes, Go, Docker, Keycloak, Apache Ranger, Ranger, PostgreSQL, Back-end, Agile, Cloud Services, Databases, SaaS, Azure, API Design, API/Services Architecture, Amazon S3 (AWS S3), Single Sign-on (SSO), Apache Kafka
Senior Mobile App Developer
2020 - 2022
Freelance
- Developed a Flutter-and-Dart-based application to manage accounting, invoices, expenses, etc.
- Designed a schema for an SQLite database so that user can store their data a mobile device.
- Developed print-and-share PDF features for invoices and other accounting documents.
- Created analytics UI and back-end services; with this users can perform analytics features like SUM, AVG, COUNT, MAX, MIN, and GROUP BY.
- Created a fully featured filter UI for analytics and list pages.
Technologies: Flutter, Redux, Go, Firebase, Dart, Material UI, ECMAScript (ES6), GraphQL, TypeScript, API Integration, REST APIs, Software Architecture, User Experience (UX), Mobile Apps, JSON, Accounting, Finance, Full-stack, User Interface (UI), GitLab, Architecture, Mobile, Apple, Mobile Development, Team Leadership, System Design
Senior Full-stack Developer
2018 - 2020
Freelance
- Worked closely with different clients to understand their requirements and pain points with their existing system and proposed a solution to the problem.
- Designed the architecture from scratch of a cloud-based business management application for a mid-size firm.
- Developed the REST APIs for the application using Go and Dgraph; chose GraphQL as the database query language to query Dgraph.
- Implemented a UI with the help of React, Redux, MUI, and some other open-source libraries of the whole business application.
- Implemented CSV exports, PDFs, statements, and report generation on the client side.
- Created a tool to increase automation and reduce errors for internal use.
- Designed and developed an end-to-end institute management app using React, Redux, and MUI for the front-end and FOXX microservice at the back end. That application was delivered to the client's on-premise server.
Technologies: React, JavaScript, Node.js, Go, Dgraph, SQLite, ArangoDB, Microservices Architecture, REST, Android, SQL, Agile Software Development, Git, Firebase Authentication, Material UI, Cloud Deployment, Web Services, Object-oriented Programming (OOP), Mobile App Development, HTML5, CSS, Docker, Kubernetes, Redux, Redux-Saga, Express.js, ECMAScript (ES6), PostgreSQL, GraphQL, MySQL, APIs, API Integration, MongoDB, React Native, REST APIs, Software Architecture, Docker Compose, Containers, Amazon Web Services (AWS), PHP, User Experience (UX), Relational Databases, JSON, Next.js, Accounting, Finance, Full-stack, User Interface (UI), GitLab, Security, Architecture, Mobile, ETL, Mobile Development, Team Leadership, Back-end, Agile, Databases, SaaS, API Design, API/Services Architecture, ESLint, Full-stack Development, System Design
Full-stack Developer
2015 - 2018
SAP
- Implemented an authorization microservice that takes less than five milliseconds for 100 concurrent requests; to achieve this, also designed and implemented a custom distributed cache using Go.
- Designed and developed REST APIs to store and retrieve users, roles, and organizational hierarchy, where we have to follow HIPPA compliance. Also implemented authorization using the user roles and organization position.
- Implemented web-based UIs and integrated with REST APIs for the app's user management module to manage users, roles, and organization hierarchy using SAPUI5.
- Designed and developed back-end services for the patient cohort management system; this system assigned or removed large numbers of patients based on different parameters and sorted them into cohorts in a single API call.
- Tested the services using unit tests and integrated the test methodology.
- Participated in the journey of the monolith to a microservice architecture where we used cloud technologies like Docker, Kubernetes, and AWS to implement microservices.
Technologies: JavaScript, SAP HANA, SAP UI5, Cloud Deployment, Go, REST, Node.js, SQL, Agile Software Development, Git, Web Services, Docker, Kubernetes, Redux, ECMAScript (ES6), PostgreSQL, Unit Testing, APIs, Jenkins, CI/CD Pipelines, API Integration, Azure Cloud Services, REST APIs, Docker Compose, Containers, Amazon Web Services (AWS), User Experience (UX), Relational Databases, SDKs, JSON, OAuth 2, SAP, OData, HIPAA Compliance, Full-stack, User Interface (UI), GitHub, WebSockets, Security, DevOps, Microservices, Back-end, Agile, Cloud Services, Databases, SaaS, API Design, API/Services Architecture, ESLint, Amazon S3 (AWS S3), Full-stack Development, Single Sign-on (SSO)
Software Developer
2014 - 2015
Vanenburg Software Pvt Ltd
- Worked as part of the core team to build a cloud-based workflow engine—designing the data model to store the workflow and revising the workflow and its instances—and achieved high throughput and low latency for a large dataset by using NoSQL.
- Designed and developed secure REST API endpoints to create, edit, delete, view, and search for workflow and its instances in Java. Here role-based authorization was used to protect the APIs from unauthorized access.
- Implemented and unit-tested a custom expression executor with the help of an open-source library in Java. That executor had two inputs, an expression as a string and an object. The output of the executor was a single value.
- Implemented and united tested various utility functions and POJO classes (plain old Java object).
Technologies: Java, NoSQL, HBase, Web Services, REST, Linux, Agile Software Development, Object-oriented Programming (OOP), Unit Testing, APIs, Apache Solr, API Integration, REST APIs, Software Architecture, JSON, XML, User Interface (UI), GitHub, Security, Back-end, Agile, Cloud Services, Databases, SaaS, API Design
Experience
Business App for A Mid-sized Firm
A React, Go, and Dgraph-based application for a mid-sized firm to implement paperless operations. The application recorded all kinds of business documents, implemented searches along with filters, and printed PDFs. It also featured role-based user authorization and a double-entry accounting system.
Business Accounting, Invoicing, and Management App
A Flutter-based app for small to mid-sized businesses to manage business accounting, invoicing, inventory and expenses, as the app allows users to perform analytics and show data in tabular format and I completed the end-to-end development from the front-end in Flutter to the back-end in dart and SQLite.
Institute Management App
A React (Material UI)-based application for institute management; it maintained all the back office tasks.
I developed the back end with ArangoDB and used ArangoDB as a document database. The front end was built using React, MUI (Material UI), and Redux for state management.
I developed the back end with ArangoDB and used ArangoDB as a document database. The front end was built using React, MUI (Material UI), and Redux for state management.
User Management Module
A HANA-based user management module for onboarding new users and managing role-based authorization, user authentication, and user administration.
We used HANA as a database, JavaScript for the back end, and SAPUI5 for the front end. I developed and maintained the user management module.
We used HANA as a database, JavaScript for the back end, and SAPUI5 for the front end. I developed and maintained the user management module.
Back End for a Workflow Engine
A Java-based workflow engine to create, manage and run workflows.
My responsibility was to design the data model and schema for HBase. I also implemented the REST API and database interaction module, and I used JUnit to test different methods.
My responsibility was to design the data model and schema for HBase. I also implemented the REST API and database interaction module, and I used JUnit to test different methods.
Education
2011 - 2014
Master's Degree in Computer Science
Cochin University of Science and Technology - Kochi, Kerala, India
Skills
Libraries/APIs
React, Node.js, Redux-Saga, REST APIs
Tools
SAP UI5, Firebase Authentication, Git, Apache Solr, Jenkins, Docker Compose, GitHub, GitLab, Keycloak
Languages
JavaScript, Go, Dart, SQL, Rust, Java, HTML5, CSS, ECMAScript (ES6), GraphQL, TypeScript, HTML, C#, PHP, XML, cXML, Python
Frameworks
Flutter, Material UI, Redux, Express.js, JUnit, React Native, OAuth 2, Next.js, Apache Ranger
Paradigms
REST, Object-oriented Programming (OOP), Agile Software Development, Microservices Architecture, Unit Testing, HIPAA Compliance, Test-driven Development (TDD), DevOps, Microservices, Mobile Development, Agile, API/Services Architecture, ETL
Storage
Databases, Database Management Systems (DBMS), NoSQL, HBase, Cloud Deployment, SQLite, ArangoDB, Dgraph, PostgreSQL, MySQL, MongoDB, Azure Cloud Services, Relational Databases, JSON, Amazon S3 (AWS S3), Redis
Platforms
SAP HANA, Linux, Android, Docker, Kubernetes, Firebase, Google Cloud Platform (GCP), Amazon Web Services (AWS), Mobile, Apple, FlutterFlow, Apache Kafka, Azure
Industry Expertise
Accounting
Other
Web Services, Software Architecture, Full-stack, User Interface (UI), Back-end, API Design, Full-stack Development, Back-end Development, Algorithms, Software Engineering, Mobile App Development, APIs, CI/CD Pipelines, API Integration, Containers, User Experience (UX), Ajax, Servers, SDKs, Mobile Apps, SOAP, SAP, OData, Finance, WebSockets, Performance, Security, Architecture, Front-end, Cloud Services, SaaS, No-code Development, ESLint, Single Sign-on (SSO), System Design, Low Code, Supabase, LDAP, Ranger, Team Leadership
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