Freelance Backend Engineers in California

Freelance Backend Engineers in CaliforniaFreelance Backend Engineers in California

Projects People

proSacramento, USA

iOS Developer & Designer: From Concept to Completion

$100k+: Earned

5x: Hired

5.0: Rating

34: Followers

iOS Developer & Designer: From Concept to Completion

Cover image for Magic, A Short Form Video Platform

Magic, A Short Form Video Platform

1

45

Cover image for OCCI Fashion Platform Redesign and Development

OCCI Fashion Platform Redesign and Development

1

9

Cover image for Follk, A Social Platform Experiment

Follk, A Social Platform Experiment

2

71

Cover image for Sage AI Chatbot Development

Sage AI Chatbot Development

2

54

Backend Engineer(1)

proSan Francisco, USA

AI Campaign Assets + Agents for DTC Growth

$50k+: Earned

19x: Hired

5.0: Rating

212: Followers

Top

Partner

+1

AI Campaign Assets + Agents for DTC Growth

Cover image for Kevin from Home Alone Telegram Bot

Kevin from Home Alone Telegram Bot

1

64

Cover image for Bespoke Punks NFT Platform

Bespoke Punks NFT Platform

1

40

Cover image for Chad: The Ultimate Crypto Degen Bot

Chad: The Ultimate Crypto Degen Bot

1

68

Cover image for Morpheus AI Persona Chatbot

Morpheus AI Persona Chatbot

0

107

Backend Engineer(14)

Aurelien GERIER

proLos Angeles, USA

Fullstack Engineer | 14+ yrs Shipping React,Next.js,Node,AI

$50k+: Earned

5x: Hired

4.9: Rating

105: Followers

Top

Fullstack Engineer | 14+ yrs Shipping React,Next.js,Node,AI

Cover image for Scalable Digital Platform for Cognitive Testing

Scalable Digital Platform for Cognitive Testing

0

31

Cover image for HumanData Web Application

HumanData Web Application

0

34

Cover image for Led delivery of a cloud-native

Led delivery of a cloud-native K-12 student wellness platform that helps counselors monitor wellbeing, surface at-risk students, and act early—balancing product velocity with FERPA/COPPA-aware design and multi-tenant isolation (API RBAC, PostgreSQL RLS, district-scoped analytics). → Owned technical direction and delivery rhythm across a TypeScript monorepo (pnpm/Turbo): backend API, web app, shared packages, DB migrations, CI/CD gates, and staged deploys to GCP (e.g. Cloud Run), aligning engineering work with roadmap and release risk. → Orchestrated an AI assistant for counselors on Google Vertex AI (Gemini): system prompts, safety settings for K-12, function-calling tool design, multi-round tool loops, and strict separation so UI widgets render from verified tool results—not model hallucinations—with tracing/feedback hooks (e.g. Langfuse) for quality and auditability. → Drove access-control and compliance posture for sensitive student data: role/permission middleware, tenant-scoped queries, and defense-in-depth database policies—documentation and evidence suitable for enterprise security reviews (e.g. SOC 2–style narratives). → Partnered on product and program management: phased feature rollout, PR/branch discipline, and clear ownership of scope vs. risk so pilot schools could onboard without compromising data boundaries. → Shaped integrations and platform boundaries: Firebase auth, Neon PostgreSQL + Drizzle ORM, real-time patterns, BigQuery analytics isolation, and operational practices (testing, lint, type-check) that keep the stack maintainable at scale. → Established a disciplined, AI-accelerated delivery model—not ad-hoc prompting: Cursor rules and Claude skills/agents for repeatable workflows; Husky + lint/type-check/test gates; GitHub Actions CI/CD; Cursor Cloud Agents for automated PR review; and daily monitoring of E2E, coverage, and critical issues—owning AI-orchestrated implementation while enforcing accuracy, consistency, and observability

0

317

Cover image for Breakjobs.ai

0

66

Backend Engineer(2)

Christine Straub

Full-Stack AI/ML Software Engineer

$50k+: Earned

1x: Hired

5.0: Rating

69: Followers

Full-Stack AI/ML Software Engineer

Cover image for EMR | EHRHealthcare Application ( HIPAA Compliant )

EMR | EHRHealthcare Application ( HIPAA Compliant )

1

211

Cover image for Empowering Pineapple Farmers through Drone Imagery Analysis

Empowering Pineapple Farmers through Drone Imagery Analysis

1

153

Cover image for The Compliance Space

The Compliance Space

0

73

Cover image for RAG with AWS Bedrock and

RAG with AWS Bedrock and React

1

537

Backend Engineer(3)

Scotty Waggoner

maxOrangevale, USA

Backend-leaning Full-stack & AI Engineer

$10k+: Earned

1x: Hired

6: Followers

Backend-leaning Full-stack & AI Engineer

Cover image for AirPay, a nearby payments app

AirPay, a nearby payments app

0

4

Cover image for Educate to Space

Educate to Space

0

14

Cover image for Ask AI for Foodnoms

Ask AI for Foodnoms

1

24

Cover image for Health Insurance Marketing and Quoting Responsive Website

Health Insurance Marketing and Quoting Responsive Website

0

14

Backend Engineer(3)

AI SaaS Engineer | MVPs, Agents, Automation, Next.js, Python

1x: Hired

8: Followers

AI SaaS Engineer | MVPs, Agents, Automation, Next.js, Python

Cover image for AI Marketing Attribution SaaS with

AI Marketing Attribution SaaS with CRM & Revenue Tracking I built PeoplePixel, an AI-powered SaaS platform designed to help businesses turn anonymous website traffic into identifiable leads and measurable revenue. The core problem was that most websites lose the majority of their visitors as “ghost traffic” without any way to identify, follow up, or measure impact. PeoplePixel solves this by combining visitor identification, CRM integration, and revenue attribution into one unified system. I designed and developed the platform end-to-end using Next.js, TypeScript, and Supabase, building a multi-tenant SaaS with authentication, team workspaces, billing, and secure data access using Row-Level Security. A key part of the product is the free traffic audit funnel. Users can enter their website URL to receive an automated analysis of missed revenue opportunities using Firecrawl and DataForSEO. This creates a strong entry point into the platform and drives conversion into the full product. On the data side, I integrated IntentWave for visitor identification and GoHighLevel as the CRM layer, syncing contacts, outreach activity, and purchase data. I then built a custom attribution engine that matches visitors to revenue using confidence-based scoring derived from email, SMS, and call engagement signals. The system runs on background pipelines using scheduled jobs and webhook ingestion to continuously process attribution data and update reporting in near real-time. The final product provides a complete ROI dashboard, including visitor insights, attributed revenue, funnel analytics, and pipeline performance, enabling businesses to clearly understand and recover lost revenue. This project highlights my ability to design and build complex SaaS platforms that combine data pipelines, third-party integrations, and product-driven user experiences into a cohesive system.

2

212

Cover image for AI Chrome Extension for Instant

AI Chrome Extension for Instant Cover Letter Generation (Job Jolt) I built Job Jolt, an AI-powered cover letter generator designed to help users create tailored job applications directly from real job listings in seconds. The product combines a Chrome extension with a backend web application to streamline the entire workflow. Users can visit a job listing on platforms like LinkedIn, extract relevant job data with a single click, and instantly generate a customized cover letter powered by AI. On the frontend, I developed a React-based Chrome extension that injects seamlessly into job listing pages. The extension handles data extraction, sanitization, and formatting before securely sending structured requests to the backend. On the backend, I built a Flask-based system integrated with OpenAI to generate high-quality, context-aware cover letters in under 20 seconds. The system was designed for speed and reliability, making it one of the fastest solutions in its category. A strong focus was placed on security and robustness. I implemented API key validation, token-based authentication, rate limiting, and secure password handling to ensure the platform could scale safely while protecting user data. The result is a smooth, end-to-end user experience that removes friction from the job application process and demonstrates how AI can be integrated directly into real-world workflows. This project highlights my ability to combine frontend UX, browser extensions, and AI-powered backend systems into a cohesive and high-performance product.

1

67

Cover image for Enterprise AI Search System with

Enterprise AI Search System with Embeddings, Pipelines & Widget Builder I worked as a Full Stack Engineer at Gloo, contributing to the architecture and development of an AI-powered discovery widget designed for large-scale content platforms. The product is an embeddable search system that enables semantic content discovery across podcasts, sermons, articles, and other media, allowing organizations to surface relevant content through intent-based search rather than traditional keyword matching. I helped design and build the system end-to-end, working across frontend, backend, and data infrastructure. On the frontend, I developed a modular widget and configuration system using Next.js, TypeScript, and modern UI tooling, enabling partners to integrate the search experience with a single script tag. A key part of the project was the widget builder interface. I built a multi-step configuration system with live preview, allowing non-technical users to customize layout, data sources, API keys, and embedding behavior in a simple and intuitive workflow. On the backend and data layer, I implemented ingestion pipelines to process large volumes of publisher content via RSS feeds. This included generating embeddings, enriching metadata, and preparing data for semantic retrieval, enabling domain-specific AI search across diverse content types. The search system itself was built using a hybrid approach. I combined vector-based semantic search using Weaviate with high-speed autocomplete and indexing via Typesense, resulting in accurate intent-based results alongside instant query suggestions. I also contributed to system reliability and observability by integrating analytics and monitoring tools, enabling detailed tracking, debugging, and performance optimization across deployments. The result is a scalable, production-grade AI search platform that can be embedded into external sites with minimal effort, providing powerful discovery capabilities backed by modern AI infrastructure. This project highlights my ability to design and build complex AI systems that combine frontend experience, backend architecture, and data pipelines into a cohesive, high-performance product.

1

139

Cover image for I led the development of

I led the development of MyOfLink as founding engineer, building a full-scale SaaS platform designed to help creators and businesses manage their online presence through advanced link infrastructure, analytics, and monetization. The goal was to go beyond traditional “link-in-bio” tools by creating a high-performance platform that improves engagement, tracks user behavior, and enables scalable monetization. I architected and built the platform end-to-end using Next.js, TypeScript, and Tailwind CSS, leveraging server-side rendering and React Server Components to significantly improve performance. The result was a fast, responsive product achieving a 95–98+ Lighthouse score and noticeably reduced load times. A core innovation was the deep-linking system. I engineered a solution to bypass in-app browser limitations on platforms like Instagram, Reddit, and TikTok using intelligent user-agent detection and platform-specific routing. This improved link conversion rates and overall user engagement by approximately 40 percent. I also built a real-time analytics dashboard to give users actionable insights into their traffic and performance. This included click-through rates, conversion metrics, and geographic data, enabling more informed decision-making for creators and businesses. On the monetization side, I implemented a full Stripe-based billing system with subscription tiers, usage-based pricing, and webhook-driven automation. The checkout experience was designed to be seamless, secure, and optimized for conversion. The final product is a high-performance SaaS platform that combines advanced linking technology, real-time analytics, and scalable monetization into a single cohesive system. This project highlights my ability to design and deliver complex SaaS products from the ground up, with a strong focus on performance, user experience, and real business outcomes.

1

96

Backend Engineer(5)

proCalifornia, USA

World-Class UX, Full-Stack, Context Engineering

13: Followers

expert

World-Class UX, Full-Stack, Context Engineering

Cover image for Full-stack Micro Web Apps 🖥️🔗⚙️

Full-stack Micro Web Apps 🖥️🔗⚙️

1

23

Cover image for Non-Profit Web Apps 🤲💙🌎

Non-Profit Web Apps 🤲💙🌎

0

7

Cover image for MBM Website, App & Rebranding

MBM Website, App & Rebranding

2

7

Cover image for Tired of paying for multiple tools just to get a basic calen...

Tired of paying for multiple tools just to get a basic calendar and kanban? 🤦‍♂️ So I built YouSoul 🐳 – Vibe Productivity AI Agent Free & Unlimited on YouBase beta. No AI slop. No pricing. No BS. BYO key What’s different? - Ask: “Add call mom tomorrow at 3 pm” - It just happens. - Ask: “What are my high-priority tasks this month?” - Instant answers - Beautiful UI, Underwater visuals, smooth motion, and ambient sounds for focus No more 5+ subscriptions! Powered by YouWare + YouBase Check it out 👇 🔗 App: https://yousoul.app/ (https://yousoul.app/)🔗 YouBase: https://yousoul.youware.app/ (https://yousoul.youware.app/)✍️ LinkedIn Post (https://www.linkedin.com/posts/whoisoak_youwarechallenge-productivity-ai-activity-7409462097467650049-Qwa-?utm_source=share&utm_medium=member_desktop&rcm=ACoAACH0bjUBmfrBHlpPfjSSAdHjfxvQlrU9uYM)

3

7

391

Backend Engineer(2)

Fullstack Dev: Expert in Ruby on Rails & Laravel

Fullstack Dev: Expert in Ruby on Rails & Laravel

Cover image for IFME Password Creation Standards

IFME Password Creation Standards

0

10

Cover image for FormulaFolios Data Processing

FormulaFolios Data Processing

0

6

Cover image for Marketing Tag Managers Setup

Marketing Tag Managers Setup

0

6

Cover image for Style Refresh / Redesign

Style Refresh / Redesign

0

6

Backend Engineer(2)