RLHF & SFT Evaluator · Team Lead

Teaching AI models
to sound more human.

AI Data Annotation & Quality Specialist

Six years into training and evaluating the systems that train language models - rating responses, rewriting weak ones, and building the QA processes that keep a 90-client annotation practice at 99%+ accuracy.

  • English (Fluent) · Yoruba (Native)
Portrait of Mercy Aisosa, AI Data Annotation and Quality Specialist, wearing a light blue suit
99%+ QA accuracy
RLHF · SFT

Impact at a glance

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years training & evaluating AI systems
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global clients served on Upwork, Top-Rated Plus
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SKUs reviewed weekly at >97% first-pass accuracy
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people trained in data annotation through community work
About Me

An AI Trainer and Entrepreneur

I'm Mercy, the COO and co-founder of Sellyt, an AI-powered platform built to transform how vendors sell online. Millions of talented vendors are hustling daily across WhatsApp, Facebook, and Instagram with no proper tools to help them grow, so we built one.

My role is to keep everything moving, from operations and team building to strategy and community. Africa's best days are ahead, and I'm growing up every day to help build that future.

What I do

How I show up every day

Operations

Running the day-to-day of Sellyt and keeping all moving parts in sync.

Team building

Recruiting, managing, and growing the Sellyt team from the ground up.

Strategy

Planning and executing Sellyt's expansion across West Africa.

Community

Growing and nurturing the Sellyt vendor community across the platform.

Partnerships

Building relationships with investors, partners, and stakeholders.

Innovation

Driving product thinking and new ideas that keep Sellyt ahead.

Achievement

Milestones so far

  • Co-founded Sellyt and led it from idea to a live platform serving vendors at scale.
  • Successfully onboarded 1,000+ beta vendors and built an active vendor community.
  • Structured and led the hiring process for the Sellyt team from scratch.
What else I do

"I Don't Just Use AI - I Teach It."

"Before building Sellyt, and alongside running it, I work as a professional AI Trainer and Annotation QA specialist, helping shape the way artificial intelligence thinks, responds, and understands the world. It's one of the most fascinating and important jobs of our generation, and I'm proud to be part of it."

Certification

Entrepreneurship training

Certificate of Completion - 2026 MTN Foundation-BOI Y'ellopreneur 3.0 Entrepreneurship Skills Training, awarded to Aisosa Mercy

2026 MTN Foundation–BOI Y'ellopreneur 3.0 Entrepreneurship Skills Training

Facilitated by the Enterprise Development Centre, Pan-Atlantic University, in partnership with MTN Foundation and Bank of Industry.

View certificate (PDF)
AI Trainer

Client's feedback

"Mercy did a great job!"

- John K.
Core Competencies

What she brings to a project

AI Tutoring & Training

Writing & reviewing model outputsText, audio, image & video annotationShaping model behaviour

LLM Training Support

RLHFSFTPrompt-response scoringSafety & helpfulness evaluation

Multimodal Data

Audio recording & reviewVideo labelingImage annotation

Annotation Tools

SuperviselyCVATLabelboxRoboflowDataloopEncordProdigyRossumAudacityBrat

Writing & Communication

Guides & reportsDialogue examplesClear, concise English

Quality & Leadership

Tiered QA99%+ accuracyTeam onboarding & mentorship
Selected Work

Six years of labels, mostly under NDA - a few she can show

Only a fraction of Mercy's project history is shareable; most client work is covered by NDA. These samples span image, text, document and audio annotation.

Image · SegmentationSemantic segmentation mask over a street scene, labeling road, cars, trees and signage in flat colour for a self-driving-car dataset
CVAT
Pixel-precise segmentation for autonomous driving

Labeled pedestrians, vehicles, trees and road signs at pixel level across high-resolution street scenes, with layered peer and supervisor QA to keep class boundaries consistent frame to frame.

Text · SentimentTwitter-style customer service conversation between a user and American Airlines, showing sentiment and reply-labeling tags
Custom labeling tool
Social media sentiment & response labeling

Classified customer-service replies by intent, tone and resolution status, tagging whether the brand response matched the user's frustration and if the issue was resolved.

Text · Claims ReviewProdigy interface showing a climate-change claim and a sentence to be marked as supporting, refuting, or not validating the claim
Prodigy
Claims & evidence annotation

Reviewed claim–evidence pairs on climate topics, researching source context before marking each sentence as supporting, refuting, or insufficient - logic that carries straight over to RLHF fact-checking.

Document · ExtractionHandwritten hotel invoice with coloured bounding boxes labeling name, email, date and price fields
LabelMe
Invoice & document field extraction

Tagged names, dates, line items and totals across handwritten and printed invoices, producing consistent, audit-ready exports for downstream model training.

Text · NERJob description with sections highlighted and tagged by category: benefits, requirements, about the company, responsibilities, and salary
Doccano
Job description segmentation

Tagged job postings by section - role, requirements, benefits, salary - against a fixed category list, keeping labels consistent across hundreds of listings.

AudioAudio waveform annotated with coloured segments labeled voicemail, human, phone tree, beep, ringing, music and noise
Label Studio · Annotation Pro
Call-audio event labeling

Segmented and classified call-audio waveforms by event type - voicemail, human speech, phone tree, ringing - using a controlled vocabulary to keep boundaries clean across long recordings.

Experience

A record of QA-led project work

2023 - Present
Annotation Quality Assurance Specialist
Humans in the Loop · Sofia, Bulgaria (Remote)
  • Runs routine quality checks and tests across image, text and video labeling tasks
  • Builds and implements QA procedures, documentation and policy
  • Identifies and resolves workflow and production issues across teams
  • Writes training materials and operating manuals, and documents every audit
2024 - 2025
Human Feedback Evaluator & Reviewer
Translated (Remote)
  • Rated text outputs on tone, accuracy and relevance to teach models safer, more helpful responses
  • Wrote curated examples used directly in RLHF and SFT training
  • Worked with engineers to refine annotation tools and workflows
2023 - Present
Product Classification & Data Reviewer
Global E · US (Remote)
  • Reviews 1,500 SKUs a week, extracting attributes and assigning HS codes at >97% first-pass accuracy
  • Flags compliance risk, cutting customs-hold incidents by 18%
  • Maintains the annotation logs and SOPs junior annotators now use daily
2021 - 2022
Data Annotator & Reviewer
Hypersentience.AI · London, UK (Remote)
  • Held 99% annotation accuracy training an AI model on audio data
  • Onboarded new hires on audio annotation practice
  • Turned model-testing results into reports the AI team used to improve performance
  • Shared weekly sprint dataset releases with the AI team
2020 - Present
Freelance Data Annotation Specialist
Upwork · Top-Rated Plus
  • Delivered multimodal datasets - text, audio, video, image - to 90+ clients worldwide at 99% QA
  • Recorded and labeled voice samples for conversational AI, tuned for natural dialogue
  • Wrote the guidelines and dialogue scenarios used to train generative AI systems
  • Managed projects end to end: scoping, onboarding, scheduling, QA
2019 - 2020
Data Annotation Specialist
Daraja Inc. · US NGO (Remote)
  • Annotated video, image and text data for model training
  • QC'd team output and halved rework rates
  • Trained junior annotators, lifting both throughput and accuracy