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Freelance Java Developer Startup Jobs in Fairfield, CA

Jobsbridge

Python Engineer

San Francisco, CA · On-site

Be it core Java, full-stack Java, Web/UI designers, Big Data or Cloud or Mobility developers ... ElasticSearch or Lucene - Experience in a fast-paced/customer-centric agile startup environmentSo ...

Amiri Recruiting

AI Support Engineer

San Francisco, CA · On-site

Proficiency in programming languages such as Python, Java, or Go * Strong organizational skills and ... Strong problem-solving skills and the ability to work in a fast-paced, dynamic startup environment.

Navigate AI

Fullstack Engineer

San Francisco, CA · On-site

$100 - $130/hr

... startup building groundbreaking technology to bring AI to the largely untapped workforce in the ... Have some product management, founder, or freelance experience * Enjoy debating architecture ...

New

Inference

Filmmaker / Storyteller

San Francisco, CA · On-site

$100K - $140K/yr

... with engineers and extract authentic stories from technical experts * Startup DNA: Thrives in ... Experience managing creative teams or freelancers What You'll Create Your work will span from ...

Boxtro Llp 123

Backend Engineer

San Francisco, CA · On-site

Koding is a developer-focused startup based in San Francisco's SOMA district. Our core product is ... Java, NodeJS, PHP, C, C++, Perl, Python...the list goes on! You can experiment with installing ...

Boxtro Llp 123

Sr. Frontend Engineer

San Francisco, CA · On-site

Koding is a developer-focused startup based in San Francisco's SOMA district. Our core product is ... Java, NodeJS, PHP, C, C++, Perl, Python...the list goes on! You can experiment with installing ...

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Freelance Java Developer Startup information

See Fairfield, CA salary details

$15

$57

$78

How much do freelance java developer startup jobs pay per hour?

As of Aug 20, 2026, the average hourly pay for freelance java developer startup in Fairfield, CA is $57.70, according to ZipRecruiter salary data. Most workers in this role earn between $49.90 and $64.57 per hour, depending on experience, location, and employer.

What is the difference between Freelance Java Developer Startup vs Freelance Java Developer Corporate?

AspectFreelance Java Developer StartupFreelance Java Developer Corporate
Work EnvironmentIndependent, flexible, project-basedRemote or office-based, structured projects
Client InteractionDirect with startups or small teamsOften with corporate clients or departments
Project ScopeVaried, often innovative or MVP developmentLong-term, maintenance, or enterprise solutions
Required CredentialsJava certification, portfolio, experienceJava certification, experience, possibly more formal credentials

Freelance Java Developer Startup roles typically involve working independently on diverse projects for startups, emphasizing innovation and flexibility. In contrast, Freelance Java Developer Corporate roles often focus on structured, long-term projects for established companies, with more formal client interactions and expectations.

Freelance Java Developer Startup jobs near you

Staff Software Engineer, AI Data Platform

Labelbox

San Francisco, CA • On-site

Full-time

Re-posted 12 days ago

Job description

Role Overview

Labelbox is the RL data factory for advancing frontier agent capabilities. We build the data, evaluations, and infrastructure that frontier labs use to train and judge their agents. We're looking for talented, experienced engineers to join us. The bar is high: engineers who have strong judgment and set technical direction, quickly build prototypes that scale into the reliable systems, and are at the frontier of agent-first engineering practices and innovating to accelerate the speed of the business.

What you may work on
  • Eval systems that run millions of agent trajectories to measure model and product quality.
  • Fine-tuning pipelines that turn evaluation signals into measurable agent improvements.
  • Agent-first product surfaces: UX and infrastructure for workflows where the user is a model or an agent operator.
  • The systems behind hundreds of thousands of AI interviews used to source and match freelance workers to projects.
  • Infrastructure that scales to the throughput frontier labs actually need.
  • Integration of the latest models and capabilities into production within days of release.
What we're looking for
  • 4+ year track record of shipping systems customers and other engineers rely on
  • You build full stack prototypes fast and they hold up. The v1 you ship becomes the foundation the rest of the team builds on.
  • Strong system and API design judgement
  • Hard architecture and product calls land with you. You make them, defend them under pressure, and update fast when someone else is right.
  • You ship production code with coding agents daily. You know where they break and what it takes to make them reliable to further accelerate the team's velocity.
  • You set direction by being the example. Other engineers reach for your designs and your code as the reference.
  • You move fast in ambiguous, startup-pace environments with influence over authority.
  • You have worked in all parts of the stack
  • Deep proficiency in TypeScript and/or Python.
Nice to have
  • Production experience building LLM- or agent-driven products.
  • Designing evaluations for LLMs and agents, or producing high-quality data for ML systems.
  • Background in production distributed systems, ML infrastructure, or data systems at scale.
Our Technology Stack

Our engineering team works with a modern tech stack designed for scalability, performance, and developer efficiency:

  • Frontend: React.js with Redux, TypeScript
  • Backend: Node.js, TypeScript, Python, some Java & Kotlin
  • APIs: GraphQL
  • Cloud & Infrastructure: Google Cloud Platform (GCP), Kubernetes
  • Databases: MySQL, Spanner, PostgreSQL
  • Queueing / Streaming: Kafka, PubSub

Apply