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Freelance Api Developer Jobs (NOW HIRING)

Solomon Page

Software Engineer II

Austin, TX · On-site

$45 - $55/hr

REST API development and integration. * SQL databases and data modeling fundamentals. * Basic ... freelancers - which sets us apart in the industries we serve. About Solomon Page Founded in 1990 ...

Outlier

Full Stack Software Engineer for AI Training

This freelance role is fully remote and offers flexible hours-you can work whenever works best for ... Experience authoring technical specifications and API contracts * Hands-on expertise with testing ...

CourtAvenue

$125 - $140/hr

... both data engineers and senior marketing stakeholders. What you'll do - Lead the technical ... API-triggered journeys, event schema). - Complex, multi-vendor program environments with shared ...

Solomon Page

Software Tester

Manhattan, NY · On-site

$53/hr

We are seeking a hands-on Software Engineer with strong expertise in Test Automation and Quality ... Design, develop, and maintain automation frameworks for UI, API, integration, regression, and smoke ...

Remitly

Principal Partnerships Manager

Seattle, WA · Hybrid

$168K - $210K/yr

Close disbursement partnerships with gig and freelance platforms that have high concentrations of ... Own the EOR and payroll vertical: source and close disbursement API partnerships with global EOR ...

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Freelance Api Developer information

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How much do freelance api developer jobs pay per hour?

As of Jul 14, 2026, the average hourly pay for freelance api developer in the United States is $59.89, according to ZipRecruiter salary data. Most workers in this role earn between $54.57 and $67.31 per hour, depending on experience, location, and employer.

How do Freelance API Developers typically coordinate with clients and other team members during a project?

Freelance API Developers often collaborate remotely with clients, project managers, and other developers using tools like Slack, Trello, or Jira. Clear communication and regular check-ins are vital to ensure alignment on project requirements, timelines, and deliverables. Developers are usually responsible for providing updates, documenting their code, and sometimes participating in code reviews or integration meetings. This collaborative approach helps ensure the API integrates smoothly with other systems and meets the client's needs.

What is the difference between Freelance Api Developer vs Freelance Software Engineer?

AspectFreelance Api DeveloperFreelance Software Engineer
Required SkillsAPI design, RESTful services, JSON/XML, programming languages like Python, JavaScriptBroad programming skills, software architecture, various programming languages
Work EnvironmentProject-based, remote or on-site, client-specificProject-based, remote or on-site, diverse industries
Industry UsageTech companies, startups, API-centric projectsTech, finance, healthcare, and many other sectors

Freelance Api Developers specialize in designing and implementing APIs, often working on specific integrations and data exchange projects. Freelance Software Engineers have a broader scope, working on entire software solutions across various industries. Both roles are project-based and often remote, but Api Developers focus more on API-specific tasks, while Software Engineers handle comprehensive software development.

What is a Freelance API Developer?

A Freelance API Developer is a self-employed software professional who specializes in creating, integrating, and maintaining Application Programming Interfaces (APIs) for clients on a contract or project basis. They work with various programming languages and frameworks to enable different software systems to communicate with each other. Freelance API Developers often collaborate with businesses, startups, or other developers to design APIs that meet specific needs, troubleshoot issues, and ensure secure and efficient data exchange. They typically manage their own schedules and work remotely or on-site, depending on the client’s requirements.

What are the key skills and qualifications needed to thrive as a Freelance API Developer, and why are they important?

To thrive as a Freelance API Developer, you need strong programming skills (often in languages like Python, JavaScript, or Java), a solid understanding of API design principles (REST, SOAP), and experience with authentication and security standards. Familiarity with API development tools such as Postman, Swagger, and version control systems like Git is typically required, along with knowledge of cloud platforms and relevant certifications. Excellent problem-solving, client communication, and time management skills help you stand out in delivering tailored solutions and managing multiple projects. These capabilities are crucial for building reliable APIs, meeting client needs, and succeeding in a competitive and dynamic freelance environment.
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What cities are hiring for Freelance Api Developer jobs? Cities with the most Freelance Api Developer job openings:
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Freelance Api Developer jobs near you
Infographic showing various Freelance Api Developer job openings in the United States as of July 2026, with employment types broken down into 91% Full Time, 3% Part Time, and 6% Contract. Highlights an 77% Physical, 4% Hybrid, and 19% Remote job distribution, with an average salary of $124,567 per year, or $59.9 per hour.
Senior Prompt Engineer: LLM Migration & Optimization

Senior Prompt Engineer: LLM Migration & Optimization

Welo Data

Charleston, WV • Remote

$96K - $132K/yr

Part-time

Re-posted 26 days ago

Job description

Are you an expert at navigating the complex architecture of Large Language Models? Welo Data is seeking a Senior Prompt Engineer to lead the technical migration of template workflows into high-performance LLM autoraters.

This role is designed for a technical specialist who understands that "perfecting a prompt" is a rigorous engineering discipline. You will leverage advanced APG/APO tools and manual refinement to ensure our automated systems meet—and exceed—human crowd baselines in accuracy and nuance.

🚀 The Mission: Automated Quality at Scale
  • Architectural Migration: Take full ownership of the end-to-end technical migration of templates to LLM autoraters.
  • Optimization Leadership: Utilize Automatic Prompt Generation (APG) and supervise Automated Prompt Optimization (APO) tools to push model performance past plateaus and deadlocks.
  • Metrics-Driven Excellence: Continuously measure quality against "gold data" baselines, tracking precision, recall, and $F_1$ scores to justify launch readiness.
  • Edge-Case Engineering: Manually draft and refine complex prompts to overcome anti-patterns and architecture gaps that automated tools can't solve.
Project Details
  • Job Title: Senior Prompt Engineer (LLM Migration)
  • Schedule: Part-Time (Set your own hours within project milestones)
  • Location: 100% Remote (Must be based in the United States)
  • Employment Type: Freelance / Independent Contractor
Candidate Profile
  • Educational Foundation: Bachelor’s, Master’s, or PhD in Computer Science, Data Science, Computational Linguistics, or a related analytical field.
  • Prompt Engineering Mastery: 4+ years of experience tuning LLMs for strict, structured outputs, complex classification, and few-shot learning.
  • Analytical Power: High proficiency in identifying error patterns and using SQL or data analytics tools to monitor performance.
  • Technical Agility: Fast learner capable of mastering proprietary internal tools and "Goose API" style interfaces with minimal oversight.
Preferred Technical Skills
  • Familiarity with shadowbot monitoring and disagreement tracking.
  • Experience in AI model evaluation and software engineering.
  • Deep understanding of semantics, logic, and Chain-of-Thought (CoT) prompting.
  • Proven ability to draft high-level Launch Certification Documentation.
Recruitment & Onboarding
  1. Technical Review: Submit your CV and portfolio of LLM optimization work.
  2. Prompt Assessment: Demonstrate your ability to navigate complex template clusters and APO deadlocks.
  3. Tooling Deep-Dive: Get access to our internal technical suite and migration workflows.
  4. Launch: Begin your part-time engagement and lead the shift to LLM-driven autorating.

Working at Welo Data

What to expect from working at Welo Data

From Welo Data

About Welo Data, in their own words

From Welo Data

Welo Data is a global AI data services company powering the next generation of AI. We build, annotate, and validate the training datasets that make AI models accurate, safe, and ready for the real world — across languages, cultures, and domains.

Our team of experts spans the globe, combining deep technical knowledge with a human-centered approach. If you want your work to shape how AI understands the world, you'll find your place here.

Diversity and inclusion statement

From Welo Data

Our Strength is derived from Winning Together. Welo Data is unequivocally committed to developing and fostering a workplace and organizational culture that values the diversity of thought and perspective delivered by a diverse global workforce operating within an inclusive organization.