Mathematics & Python Specialist - Freelance AI Trainer

Please submit your CV in English and indicate your English proficiency level. Mindrift connects skilled professionals with project-based AI assignments for leading technology companies. These projects focus on assessing, evaluating, and improving AI systems. Participation is on a project basis and does not represent permanent employment. What you will do Create original computational mathematics problems that mirror real mathematical research workflows Design problems requiring Python programming to solve, using libraries such as Numpy, SciPy, or Sympy Ensure problems are computationally intensive and cannot be solved manually in a reasonable timeframe Develop problems involving complex reasoning in areas like number theory, combinatorics, graph theory, and numerical analysis Base scenarios on real-world research challenges or practical mathematical applications Validate solutions using Python and standard mathematical libraries Document problem statements clearly and provide accurate, verified solutions Requirements Degree in Mathematics (Pure or Applied) or a related field Proficiency in Python for numerical validation; experience with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or other relevant programming languages is also considered At least 2 years of professional experience in applied mathematics, research, or teaching Background in numerical methods and symbolic computation Ability to design problems reflecting authentic mathematical research processes Understanding of computational complexity theory Excellent written English skills (C1+ level) How to apply The application process includes: Apply → Pass qualifications → Join a project → Complete tasks → Get compensated. Time commitment Tasks typically require around 10–20 hours per week during active project phases. Actual workload may vary depending on project needs. Compensation Contributors may earn up to $76 per hour, depending on expertise and pace. Earnings vary by project scope, complexity, and required skills. Other projects on the platform may offer different compensation based on their requirements.

Toloka AI is looking for a Freelance AI Trainer with a strong background in biology and Python. This remote contract role is open to candidates based in San Antonio, Texas, or elsewhere in the United States. Role overview This position centers on training and improving AI models for applications in biology. The work involves applying both subject matter knowledge and Python skills to help shape technology that supports research and education in the life sciences. What you will do Use expertise in biology and Python to guide the development of AI models Contribute to projects that aim to advance tools for biological research and learning Requirements Strong knowledge of biology Proficiency with Python Interest in AI model training and improvement

toloka-ai seeks a freelance AI Trainer who combines expertise in civil engineering with strong Python programming skills. This fully remote contract centers on supporting learners interested in artificial intelligence, with a focus on candidates based in San Antonio, Texas. Role overview This position involves sharing technical knowledge and practical experience to help others build their skills in AI. The work is project-based and offers flexibility in schedule and approach. What you will do Mentor and guide individuals exploring AI, using a background in civil engineering and Python to clarify concepts. Assist others in developing technical skills and understanding foundational topics relevant to artificial intelligence. Location This role is remote, with a preference for those located in San Antonio, Texas, United States.

Please submit your CV in English and specify your English proficiency level. This freelance, project-based role with Mindrift connects mechanical engineering professionals skilled in Python to contribute to AI projects for leading technology companies. Work is remote, with a focus on assignments for clients in San Antonio, Texas, United States. What you will do Design computational engineering problems that reflect real-world scenarios and processes Create challenges that involve Python programming for engineering calculations and simulations Develop tasks that require numerical methods or iterative approaches, ensuring computational intensity Build scenarios focused on system design, optimization, and analytical problem-solving Base assignments on actual research challenges or practical engineering applications Validate solutions using Python and standard engineering libraries Document problem statements and provide verified solutions Requirements Degree in Mechanical Engineering or a related discipline Proficiency in Python for numerical validation; experience with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or other domain-specific languages is a plus Minimum of 2 years of relevant experience (applied, research, or teaching) Solid understanding of practical engineering constraints and approximations Excellent written English skills (C1 level or above) Professional certifications (such as CMME, SAS, CAP) and experience with international or applied projects are advantageous Project workflow Apply Pass qualifications Join a project Complete assigned tasks Receive compensation Time commitment Active project phases typically require an estimated 10–20 hours per week. Actual workload may vary depending on project needs. Compensation Earn up to $69 per hour, with rates based on expertise and pace. Compensation varies by project, reflecting scope, complexity, and required skills.

We invite you to submit your resume in English, clearly indicating your level of English proficiency.Mindrift connects talented specialists with project-based AI opportunities for top-tier tech firms, focusing on testing, evaluating, and enhancing AI systems. Note: This role is project-based and does not offer permanent employment.Role Overview:Each project presents unique challenges, including but not limited to:Designing original computational physics problems that reflect genuine research workflows;Formulating problems requiring Python programming solutions (utilizing libraries such as Numpy, SciPy, and Sympy);Creating problems that are computationally demanding, ensuring they cannot be solved manually within practical timeframes (days or weeks);Developing intricate problems necessitating advanced reasoning in mechanics, electromagnetism, thermodynamics, and quantum mechanics;Grounding problems in actual research dilemmas or applicable real-world physics scenarios;Verifying solutions through Python using standard physics simulation libraries;Writing clear and comprehensive problem statements along with verified correct answers.Candidate Profile:This opportunity is ideal for individuals with a physics background and Python expertise, seeking part-time, non-permanent projects. The ideal candidates will possess:A degree in Physics (Theoretical, Experimental, or Computational) or related disciplines;Proficiency in Python for numerical validation (knowledge of MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar programming languages is also acceptable);A minimum of 2 years of relevant experience, including applied, research, or teaching roles;Familiarity with numerical simulation techniques;Capability to design problems that emulate authentic physics research workflows;Creative problem-solving skills across various physics domains;Solid command of written English (C1+ level).Project Workflow:To participate, follow these steps: Apply → Pass qualifications → Join a project → Complete tasks → Receive compensation.Expected Commitment:For this project, contributors can expect to dedicate approximately 10–20 hours per week during active phases, contingent upon project requirements. Note that this is an estimate and not a guaranteed workload.Compensation:Participants in this project can earn up to $76 per hour, depending on their proficiency and contribution pace. Compensation may vary by project based on its scope, complexity, and the expertise required. Please be aware that other projects on the platform may offer different compensation rates based on their specific needs.

Please submit your CV in English and indicate your level of English proficiency. Toloka AI, working with Mindrift, offers freelance, project-based assignments focused on advancing AI systems for technology clients. This contract role is temporary and centers on evaluating and improving AI through real-world engineering challenges. The position is remote and based in San Antonio, Texas, United States. Role overview This freelance assignment involves designing and validating material science problems that reflect actual engineering workflows. Assignments require both subject matter expertise and strong Python programming skills to create, test, and document computationally intensive tasks. What you will do Develop material engineering challenges based on authentic research questions or practical scenarios. Create problems that require Python programming for calculations, simulations, and numerical analysis. Ensure tasks involve computational complexity, using numerical methods or iterative solutions where appropriate. Design assignments related to system design, optimization, and analysis. Validate all solutions using Python and standard engineering libraries. Document each problem clearly and provide accurate, verified solutions. Requirements Degree in Material Science or a closely related discipline. Proficiency in Python for numerical validation. Experience with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar tools is a plus. Minimum of 2 years of professional experience in applied, research, or teaching roles. Solid understanding of engineering constraints and practical approximations. Excellent written English (C1 level or above). Project workflow Application Qualification Assessment Project Engagement Task Completion Compensation Time commitment During active project phases, expect to dedicate approximately 10–20 hours per week. Actual workload may fluctuate based on project requirements. Compensation Contributors may earn up to $76 per hour, depending on project complexity, contribution level, and pace. Compensation varies by assignment and expertise required. Other projects on the platform may offer different rates.

Mindrift connects chemistry experts with project-based AI work for leading tech companies. Projects focus on testing, evaluating, and improving AI systems. All roles are freelance and do not represent permanent employment. What you will do Create original computational chemistry problems that reflect real-world research workflows. Develop problems requiring Python programming solutions, using libraries such as numpy, scipy, and chemistry-specific packages. Ensure problems are computationally complex and not solvable manually within days or weeks. Design tasks that involve advanced reasoning in physical chemistry, quantum chemistry, and molecular modeling. Base problems on actual research challenges or practical chemistry applications. Validate solutions in Python using established computational chemistry methods. Write clear problem statements and provide verified solutions. Requirements Degree in Chemistry or a related discipline. Proficiency in Python for numerical validation. Familiarity with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar tools is also considered. At least 2 years of relevant experience in applied work, research, or teaching. Experience with numerical methods in chemistry. Understanding of computational chemistry concepts and techniques. Strong written English skills at C1 level or higher. How it works Submit an application and CV in English, including your English proficiency level. The process follows these steps: Apply Pass qualifications Join a project Complete assigned tasks Receive payment Project details During active project phases, tasks typically require 10-20 hours per week. Actual workload depends on project needs and may vary. Compensation Rates can reach up to $76 per hour, depending on expertise and contribution. Compensation varies by project scope, complexity, and the specialized knowledge required. Different projects may offer different rates based on their requirements.

Please submit your CV in English and indicate your English proficiency level. Mindrift offers project-based contract work for specialists interested in AI projects with leading technology companies. The primary focus is on testing, evaluating, and improving AI systems. This contract role is not a permanent employment position. Role overview The Freelance AI Trainer specializing in Statistics and Python will design original computational statistics problems that mirror real-world mathematical research. The work involves creating challenging tasks that require advanced Python programming, often using libraries like Numpy, SciPy, and Sympy. Problems should be computationally intensive, sometimes requiring days or weeks to solve, and should reflect authentic research scenarios or practical mathematical applications. Key responsibilities Create original statistics problems grounded in real research workflows. Develop problem sets that require Python programming to solve, using libraries such as Numpy, SciPy, and Sympy. Ensure problems are complex and computationally demanding. Incorporate advanced topics such as number theory, combinatorics, graph theory, and numerical analysis. Validate solutions with Python and established mathematical libraries. Document clear problem statements and provide verified solutions. Requirements Degree in Statistics or a related field. Proficiency in Python for numerical validation. Familiarity with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar tools is valued. At least 2 years of professional experience, which may include applied research or teaching. Strong written English skills at C1 level or above. Professional certifications (such as CMME, SAS Certifications, CAP) and international or applied project experience are considered a plus. How to apply Apply Pass qualifications Join a project Complete tasks Receive compensation Time commitment During active project phases, expect to dedicate about 10–20 hours per week. Workload may fluctuate based on project needs. Compensation Contributors can earn up to $73 per hour, depending on expertise and speed. Rates vary by project, considering scope, complexity, and required skills. Other projects on the platform may offer different pay structures. Location This is a remote, project-based contract. Candidates based in San Antonio, Texas, United States are welcome to apply.

Please submit your CV in English and indicate your level of English proficiency. toloka-ai, working through Mindrift, offers project-based freelance work for research physicists with Python skills. This role centers on testing, evaluating, and improving AI systems by creating and validating computational physics problems. Projects are temporary and do not constitute permanent employment. Key Responsibilities Develop original computational physics problems that reflect authentic research workflows. Create assignments requiring Python programming, often using libraries such as Numpy, SciPy, or Sympy. Design problems complex enough to require computational solutions rather than manual calculation. Build scenarios involving advanced reasoning in fields like mechanics, electromagnetism, thermodynamics, and quantum mechanics. Draw on real research issues or practical applications in physics for problem design. Validate solutions using Python and standard physics simulation tools. Document each problem statement clearly and provide verified solutions. Requirements Degree in Physics (theoretical, experimental, or computational) or a closely related field. Strong Python skills for numerical validation. Experience with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar libraries is valued. Minimum of 2 years of relevant experience in applied research or teaching. Background in numerical simulation techniques. Ability to design problems that mirror real-world research workflows. Creative problem-solving across multiple physics disciplines. Familiarity with physics modeling and approximation methods. Excellent written English at C1 level or above. Application Process Submit an application for the role. Complete the required qualifications. Join a project if selected. Work on assigned tasks. Receive compensation for completed work. Time Commitment During active project periods, tasks generally require 10–20 hours per week. Actual workload may vary with project demand and is not guaranteed outside active phases. Compensation Contributors can earn up to $76 per hour, depending on experience and pace. Compensation varies by project based on scope, complexity, and required expertise. Location This is a remote, project-based position. Candidates based in San Antonio, Texas, United States are encouraged to apply.

Please submit your CV in English and include your English proficiency level. toloka-ai, through Mindrift, offers freelance, project-based assignments for quantum research scientists with strong Python skills. These projects focus on testing, evaluating, and improving AI systems for leading technology companies. Roles are contract-based and not permanent employment. Project Scope Design computational physics problems that reflect real research workflows. Create problems requiring Python programming, using libraries like Numpy, SciPy, and Sympy. Ensure problems are complex and computationally intensive, taking days or weeks to solve manually. Develop challenges involving advanced reasoning in mechanics, electromagnetism, thermodynamics, and quantum mechanics. Base problem scenarios on real research or practical physics applications. Validate solutions with Python and standard physics simulation libraries. Clearly document each problem statement and provide verified answers. Requirements Background in quantum research and strong Python programming skills. Degree in Physics (theoretical, experimental, or computational) or a related field. Proficiency in Python for numerical validation. Familiarity with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar tools is also valued. Minimum of 2 years of professional experience in applied research or teaching. Experience with numerical simulation methods. Ability to design problems that mirror real research workflows in physics. Creative approach to developing problems across multiple areas of physics. Understanding of modeling and approximation techniques in physics. Strong written English skills at C1 level or higher. Application Process Submit your application. Complete the required qualifications. Join a project. Finish assigned tasks. Receive payment. Time Commitment During active project periods, expect to spend approximately 10–20 hours per week. Actual workload may vary depending on project needs and is not guaranteed. Compensation Earnings can reach up to $76 per hour, depending on experience, project complexity, and pace. Compensation varies by project and is determined by the scope and required expertise. Location This is a remote contract role. Candidates based in San Antonio, Texas, United States are encouraged to apply.

Please submit your CV in English and specify your English proficiency level. Mindrift connects experienced professionals with project-based assignments to help technology companies test, evaluate, and improve AI systems. These roles are not permanent positions but offer flexible, freelance work. Role overview This freelance opportunity is designed for electrical engineers with strong Python skills who are interested in part-time, project-based work. The main focus is on designing and validating computational engineering challenges that mirror real-world engineering scenarios. Create engineering problems that simulate authentic processes and require Python programming for calculations and simulations Develop computationally intensive challenges involving numerical or iterative methods Focus on system design, optimization, or analysis in the problems you create Base each challenge on real research or practical engineering applications Validate solutions using Python and established engineering libraries Document each problem statement clearly and provide verified solutions Requirements Degree in Electrical Engineering or a related discipline Proficiency in Python for numerical validation; familiarity with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar tools is a plus Minimum of 2 years of professional experience in applied work, research, or teaching Understanding of practical engineering constraints and approximations Strong written English skills at C1 level or higher Professional certifications such as CMME, SAS Certifications, CAP, and experience with international or applied projects are advantageous Project workflow Submit your application Complete qualification steps Join a project Work on assigned tasks Receive payment Time commitment Most project phases require an estimated 10-20 hours per week. Actual workload may vary depending on project needs and timing. Compensation Earnings can reach up to $69 per hour, depending on expertise and project complexity. Rates may differ by assignment based on scope and required skills. Location This is a remote contract role based in San Antonio, Texas, United States.

Submit your CV in English and indicate your proficiency level. Role overview This freelance, project-based role at Mindrift focuses on evaluating, testing, and improving AI systems for leading technology companies. Assignments connect specialized optical engineering talent with AI-driven projects. The position is not permanent employment, and work is remote from San Antonio, Texas, or elsewhere in the United States. What you will do Create original computational physics problems modeled after real-world research workflows. Develop Python-based solutions using libraries such as Numpy, SciPy, and Sympy. Design computationally intensive problems that cannot be solved by hand in a reasonable time. Formulate advanced problems in mechanics, electromagnetism, thermodynamics, and quantum mechanics. Draw from authentic research challenges or practical physics applications. Validate solutions using Python and standard physics simulation libraries. Document each problem statement and provide verified, correct solutions. Requirements Degree in Physics (theoretical, experimental, or computational) or a related discipline. Proficiency in Python for numerical validation. Experience with MATLAB, R, C, SQL, Numpy, Pandas, SciPy, or similar tools is a plus. At least 2 years of professional experience in applied, research, or teaching roles. Background in numerical simulation techniques. Ability to design problems reflecting real research workflows in physics. Creativity in developing problems across multiple areas of physics. Understanding of physics modeling and approximation methods. Strong written English skills at C1 level or above. How to apply Submit your CV. Meet the qualification criteria. Join a project. Complete assigned tasks. Receive compensation. Project commitment During active project periods, expect to dedicate around 10–20 hours per week. Actual workload may vary and is not guaranteed outside of these phases. Compensation Earnings can reach up to $76 per hour, depending on expertise and the rate of task completion. Compensation varies by project scope, complexity, and required proficiency. Other projects on the Mindrift platform may offer different rates based on specific requirements.

Toloka AI is hiring a Freelance English Writer & AI Trainer for a remote contract position based in San Antonio, Texas. This role centers on developing and refining training materials that support AI technologies. Collaboration with a distributed team is key to ensuring all content is clear, effective, and up to a high standard. Responsibilities Create and edit English-language training resources used by AI systems Review content with team members to improve quality and clarity Contribute to materials that help make AI tools more accurate and useful Requirements Strong written English skills Keen attention to detail when creating and editing content Ability to work both independently and collaboratively with a remote team

Toloka AI is looking for a Freelance Junior Journalist - AI Trainer to join projects remotely from San Antonio, Texas. This role combines journalism with practical work in artificial intelligence. It offers the chance to explore emerging topics in AI while sharpening reporting and writing skills. What you will do Support projects that advance the development and understanding of AI technologies Use journalistic techniques to help improve AI systems Stay informed about current trends and tools in artificial intelligence Location This is a remote position for candidates based in San Antonio, Texas, United States.

Mindrift brings together specialists for project-based roles in the AI sector, working with major technology companies to test, evaluate, and improve AI systems. This position is not a permanent job but offers freelance, project-driven work. Role overview The Freelance AI Trainer & Supply Chain Consultant role centers on applying procurement and supply chain expertise to help shape, test, and refine AI models. Work involves developing realistic disruption scenarios, outlining mitigation strategies, and reviewing AI-generated recommendations for accuracy and business fit. Projects typically relate to manufacturing and procurement, with a strong focus on ERP systems. What you will do Develop supply chain disruption scenarios based on real manufacturing and procurement challenges, such as supplier delays, quantity changes, logistics issues, and quality failures. Define expected results and effective mitigation strategies for each scenario. Review and evaluate AI-generated recommendations using practical business logic. Check outputs for accuracy, completeness, and relevance within ERP platforms, especially Microsoft Dynamics 365, Coupa, Jaggaer, and Ariba (SAP). Contribute to structured data creation and validation following provided guidelines. Requirements Minimum of 4 years in procurement, supply chain management, or purchasing, ideally within a manufacturing context. Strong grasp of procurement workflows, including purchase orders, vendor management, inventory, and production planning. Experience with ERP systems such as SAP, Oracle, or Microsoft Dynamics 365. Background in designing and analyzing supply chain disruption scenarios and mitigation strategies. Understanding of disruption types: delays, shortages, quality issues, and logistics challenges. Familiarity with Incoterms and logistics or transportation management. Knowledge of Bill of Materials (BOM) structures and production planning processes. Experience tracking supplier performance metrics like OTIF (On Time In Full), lead times, and quality scores. Strong analytical skills to assess AI outputs with real-world business logic. Experience in data validation, structured data entry, or annotation work. Excellent written English communication skills. Project commitment Plan for approximately 10-20 hours per week during active project periods. Actual workload may shift based on project needs. Compensation Rates reach up to $60 per hour, depending on experience and specific project requirements. Application process Apply Complete qualification steps Join a project Carry out assigned tasks Receive payment

Toloka AI is looking for a Freelance Legal Consultant with strong experience in US law. This contract position centers on training AI systems to better understand and generate legal content that aligns with US legal standards. Key responsibilities Review and evaluate legal materials to support AI training Offer guidance to ensure AI-generated content accurately reflects US legal principles Share legal expertise to inform the direction of AI product development Remote work This role is fully remote. Candidates may work from San Antonio, Texas, or anywhere within the United States.

Role overview Toloka Annotators seeks a Freelance AI Trainer - Data Annotation Specialist to help strengthen machine learning models. This position is remote and open to candidates in San Antonio, Texas, or anywhere in the United States. The main focus is on annotating and reviewing large datasets to support AI development. What you will do Review and annotate data for AI projects Check labels for accuracy and consistency on each assignment Work as part of a team to uphold high standards for data quality Remote work This role is fully remote. Team members collaborate online and complete tasks from home.

Please submit your resume in English and specify your proficiency level. Toloka brings together detail-oriented freelancers worldwide to contribute to projects that help train and improve artificial intelligence systems. The platform connects people with tasks in Generative AI for leading technology companies, relying on human input to advance AI’s accuracy and reliability. Role overview This freelance, remote position focuses on supporting AI development through human feedback. As an English Annotator - AI Trainer, tasks may include evaluating AI-generated content, checking facts, or comparing different responses. Project assignments depend on availability and Toloka’s current needs. Main responsibilities Review data sets, which may include text, images, or videos Label or categorize content following specific project instructions Identify and report content that is factually incorrect, sensitive, inappropriate, or unclear Project availability and compensation Assignments are project-based and depend on eligibility and current opportunities. Each project offers its own pay structure. For this project, AI Trainers can earn up to $23 per hour. Location This role is remote and open to candidates in San Antonio, Texas, United States.

Mindrift brings together technical specialists and AI-driven projects from major technology innovators. The platform’s goal is to blend generative AI with real-world expertise from a global network. Role overview This part-time, contract position focuses on building and maintaining Python-based data scraping workflows for the Tendem project. The role is open to candidates in San Antonio, Texas, or working remotely from anywhere in the United States. As a Freelance Python Data Scraping Engineer, you will work within a hybrid system that combines AI and human input. Internally, this position is known as an AI Pilot, collaborating with Tendem Agents who manage routine tasks. The AI Pilot uses domain expertise and quality assurance skills to deliver reliable, actionable datasets. What you will do Oversee end-to-end data extraction workflows on complex websites, ensuring accurate and well-structured results. Utilize internal tools such as Apify and OpenRouter, along with custom Python scripts, to manage data collection, validation, and processing. Adjust extraction methods for dynamic or JavaScript-heavy sites, refining techniques as website behaviors evolve. Apply data quality checks, including validation, cross-source consistency, and adherence to formatting standards before delivering datasets. Scale up scraping operations for large data sets using batching or parallelization, monitor workflow stability, and address errors from minor site changes. Requirements Minimum of 3 years’ experience in data engineering, web scraping, automation, or a closely related technical field. Strong Python programming skills and practical experience with data extraction tools. Demonstrated ability to think critically and solve problems. High attention to detail and a strong focus on data quality. Compensation Earn up to $32 per hour, depending on experience and contribution speed. Actual pay depends on project scope, complexity, and required expertise. Other projects may offer different rates. How to apply Submit your application to this post. Qualified candidates may be invited to work on projects that align with their technical skills and availability. Projects include coding, automation, and optimizing AI outputs, contributing directly to practical AI applications.

Please submit your CV in English and include your English proficiency level. Mindrift offers project-based roles for professionals interested in artificial intelligence. The company works with technology partners to test, evaluate, and improve AI systems. All positions are project-based and do not lead to permanent employment. Role overview The Freelance Legal Advisor (US Bar Admitted) - AI Project Specialist works on a range of assignments focused on AI and legal reasoning. Typical tasks include: Creating prompts that test and challenge AI systems Assessing AI-generated content for accuracy, logical soundness, and potential assumptions Improving AI reasoning to ensure it aligns with established legal standards Using structured criteria to evaluate how AI handles multi-step legal problem-solving Requirements Law degree (Bachelor, J.D., LLM, or FLLM) from an accredited US institution At least 2 years of legal practice experience in the United States Exceptional written English skills (C1/C2 proficiency) Reliable internet connection Who succeeds in this role This position fits legal consultants and attorneys with US law backgrounds who want flexible, part-time project work. Workload and commitment Contributors usually dedicate 10–20 hours per week during active projects. Actual hours may vary based on project needs. Compensation Earnings can reach up to $75 per hour, depending on expertise and task completion speed. Rates vary by project scope, complexity, and required skills. How to apply Apply Pass qualifications Join a project Complete tasks Receive payment