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Stephen Ndiritu

Stephen Ndiritu

Data Annotation & AI Training Contributor (Text/NLP)

Kenya flagNairobi, Kenya
$25.00/hrExpertMercorTolokaData Annotation Tech

Key Skills

Software

MercorMercor
TolokaToloka
Data Annotation TechData Annotation Tech
Label StudioLabel Studio
CVATCVAT
LabelboxLabelbox
Scale AIScale AI

Top Subject Matter

Ai/nlp Domain Expertise
Computer Vision
Speech/Audio Processing

Top Data Types

TextText
DocumentDocument
ImageImage
AudioAudio

Top Task Types

ClassificationClassification
Entity (NER) ClassificationEntity (NER) Classification
Object DetectionObject Detection
TranscriptionTranscription

Freelancer Overview

Data Annotation & AI Training Contributor (Text/NLP). Brings 7+ years of professional experience across legal operations, contract review, compliance, and structured analysis. Core strengths include Mercor, Labelbox, and Toloka. Education includes Bachelor of Science, St. Paul's University (2025). AI-training focus includes data types such as Text, Image, and Audio and labeling workflows including Entity (NER) Classification, Object Detection, and Transcription.

ExpertEnglish

Labeling Experience

Scale AI

Data Annotation & AI Training Contributor (Freelance)

Scale AIAudioClassificationTranscription
As a freelance data annotation and AI training contributor, I performed diverse NLP annotation tasks supporting large language model development. I classified text, performed named entity recognition, rated sentiment, and evaluated AI-generated code and textual responses. I also conducted RLHF evaluation and worked on multilingual annotation projects in English and Swahili. • Maintained annotation accuracy above platform thresholds and escalated ambiguous or edge cases for review. • Followed platform-specific annotation guidelines and documented feedback loops for continuous improvement. • Rated and ranked AI model outputs for quality and factual consistency. • Used platforms including Mercor, Toloka, and DataAnnotation.tech with tools like Label Studio and CVAT.

As a freelance data annotation and AI training contributor, I performed diverse NLP annotation tasks supporting large language model development. I classified text, performed named entity recognition, rated sentiment, and evaluated AI-generated code and textual responses. I also conducted RLHF evaluation and worked on multilingual annotation projects in English and Swahili. • Maintained annotation accuracy above platform thresholds and escalated ambiguous or edge cases for review. • Followed platform-specific annotation guidelines and documented feedback loops for continuous improvement. • Rated and ranked AI model outputs for quality and factual consistency. • Used platforms including Mercor, Toloka, and DataAnnotation.tech with tools like Label Studio and CVAT.

2024 - Present

Education

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St. Paul's University

Bachelor of Science, Computer Science

Bachelor of Science
2021 - 2025

Work History

S

Shinka Academy Of Design

ICT Instructor

Nairobi
2025 - 2025
G

Gathoni Park Farm

Digital Support & Farm Operations Assistant

Nairobi
2022 - 2025