Joel Mathinji

Key Skills

Software

AWS SageMaker

Lionbridge

Telus

Other

Clickworker

OneForma

Top Subject Matter

Ai/nlp Domain Expertise

Prompts Domain Expertise

and response evaluation

Top Data Types

Text

Image

Audio

Video

Document

Top Task Types

Classification

Transcription

Segmentation

Freelancer Overview

Prompt & Response Evaluation Specialist. Brings 4+ years of professional experience across complex professional workflows, research, and quality-focused execution. Core strengths include AWS SageMaker, Lionbridge, and Telus. Education includes Bachelor of Science, Machakos University (2025). AI-training focus includes data types such as Text, Image, and Audio and labeling workflows including Evaluation, Rating, and Classification.

Labeling Experience

Search Query Evaluation Specialist

LionbridgeTextClassification

At Lionbridge, I served as a Search Query Evaluation Specialist, reviewing customer queries for major e-commerce platforms. I classified and annotated search queries and their relevance to products, focusing on semantic and commercial relationships. My responsibilities included intent identification and detailed product attribute recognition. • Annotated and classified large search query datasets. • Assessed relationships between queries and products. • Conducted quality assurance for annotation accuracy. • Supported e-commerce search engine optimization.

At Lionbridge, I served as a Search Query Evaluation Specialist, reviewing customer queries for major e-commerce platforms. I classified and annotated search queries and their relevance to products, focusing on semantic and commercial relationships. My responsibilities included intent identification and detailed product attribute recognition. • Annotated and classified large search query datasets. • Assessed relationships between queries and products. • Conducted quality assurance for annotation accuracy. • Supported e-commerce search engine optimization.

2025 - Present

Prompt & Response Evaluation Specialist

Aws SagemakerText

As a Prompt & Response Evaluation Specialist at REVELO, I conducted expert-level prompt classification and evaluated AI agent responses. I focused on pairing prompts and responses, emphasizing correctness, harmlessness, and relevance within structured evaluation environments. Using SMGT/SageMaker tools, I maintained rigorous confidentiality and benchmarking consistency. • Classified prompts for clarity, realism, and domain accuracy. • Evaluated AI-generated responses against rubric standards. • Produced structured justifications for benchmarking. • Worked within AWS SageMaker labeling environments.

As a Prompt & Response Evaluation Specialist at REVELO, I conducted expert-level prompt classification and evaluated AI agent responses. I focused on pairing prompts and responses, emphasizing correctness, harmlessness, and relevance within structured evaluation environments. Using SMGT/SageMaker tools, I maintained rigorous confidentiality and benchmarking consistency. • Classified prompts for clarity, realism, and domain accuracy. • Evaluated AI-generated responses against rubric standards. • Produced structured justifications for benchmarking. • Worked within AWS SageMaker labeling environments.

2025 - Present

Web Scraper & AI Data Operations Specialist

OtherImageSegmentation

At Execo, I served as a Web Scraper & AI Data Operations Specialist performing image segmentation, object detection, and annotation for AI pipelines. I maintained high-precision labeled datasets, validated outputs, and applied consistent QA/QC standards across all annotation work. Collaboration with distributed AI teams was vital to ensure timely, high-quality data delivery. • Executed image segmentation and object detection tasks. • Cleaned, validated, and organized large AI datasets. • Validated annotation accuracy for production workflows. • Met quality benchmarks for remote AI teams.

At Execo, I served as a Web Scraper & AI Data Operations Specialist performing image segmentation, object detection, and annotation for AI pipelines. I maintained high-precision labeled datasets, validated outputs, and applied consistent QA/QC standards across all annotation work. Collaboration with distributed AI teams was vital to ensure timely, high-quality data delivery. • Executed image segmentation and object detection tasks. • Cleaned, validated, and organized large AI datasets. • Validated annotation accuracy for production workflows. • Met quality benchmarks for remote AI teams.

2023 - Present

AI Data Annotation Specialist

TelusTextClassification

As an AI Data Annotation Specialist at TELUS International, I annotated and categorized multimodal datasets for ML training and evaluation. I consistently applied predefined taxonomies and quality standards across various data types. Quality assurance and compliance with production standards were core parts of my role. • Annotated text, image, audio, and video datasets. • Applied taxonomies to maintain annotation accuracy. • Conducted continuous QA/QC checks. • Supported ML model training initiatives.

As an AI Data Annotation Specialist at TELUS International, I annotated and categorized multimodal datasets for ML training and evaluation. I consistently applied predefined taxonomies and quality standards across various data types. Quality assurance and compliance with production standards were core parts of my role. • Annotated text, image, audio, and video datasets. • Applied taxonomies to maintain annotation accuracy. • Conducted continuous QA/QC checks. • Supported ML model training initiatives.

2025 - 2025

Data Annotation Specialist

OtherImageClassification

At RWS Company, my role as Data Annotation Specialist focused on high-accuracy annotation across image, audio, and video datasets. I performed relevance comparisons and contributed to content quality assessments to support model training. I supplied reliable, consistent annotations for use in diverse AI applications. • Delivered high-precision annotations for multiple data types. • Executed pairwise content relevance comparisons. • Supported model training quality assessments. • Maintained annotation reliability for project teams.

At RWS Company, my role as Data Annotation Specialist focused on high-accuracy annotation across image, audio, and video datasets. I performed relevance comparisons and contributed to content quality assessments to support model training. I supplied reliable, consistent annotations for use in diverse AI applications. • Delivered high-precision annotations for multiple data types. • Executed pairwise content relevance comparisons. • Supported model training quality assessments. • Maintained annotation reliability for project teams.

2024 - 2025

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Education

Work History