Senior AI Data Annotation Jobs in Portland

Senior AI data annotation professionals support real-world AI/ML training workflows by creating and validating high-quality labeled data for LLMs, NLP, and computer vision systems. On Rex.zone, these remote full-time roles focus on training data quality, annotation guidelines compliance, RLHF and prompt evaluation, and QA evaluation to drive model performance improvement across large language model evaluation, content safety labeling, and structured tasks like named entity recognition. If you are experienced with data labeling operations, ambiguity resolution, and audit-ready documentation, explore Rex.zone opportunities aligned to Portland-based talent seeking remote work in AI data operations.

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Job: Senior AI Data Annotation Specialist (Portland)

Title: Senior AI Data Annotation Specialist (Portland) Date: 25-02-2026 Company: Rex.zone Country: US Remote Type: Remote Employment Type: FULL_TIME Experience Level: Mid-Senior Industry: Technology Job Function: Engineering Skills: AI data annotation, data labeling, RLHF, prompt evaluation, QA evaluation, annotation guidelines, training data quality, named entity recognition, content safety labeling, LLM evaluation Salary Currency: USD Salary Min: 63360 Salary Max: 126720 Pay Period: YEAR You will lead end-to-end data annotation workflows for LLM and multimodal training pipelines, ensuring training data quality and consistent labeling across projects. You will apply annotation guidelines compliance, perform QA evaluation and audit sampling, and collaborate with engineers and researchers to resolve edge cases that impact model behavior. Typical tasks include RLHF preference ranking, prompt evaluation, content safety labeling, named entity recognition for NLP datasets, and computer vision annotation quality checks. You will document decisions, calibrate labelers, and help define acceptance criteria that translate directly into model performance improvement. Responsibilities: - Own dataset-level quality strategy, including gold sets, inter-annotator agreement, and error taxonomies. - Execute RLHF and large language model evaluation tasks such as pairwise ranking and rubric-based scoring. - Perform QA evaluation on labeled data, identify systematic issues, and drive corrective actions. - Improve annotation guidelines, ambiguity handling, and escalation workflows for complex edge cases. - Coordinate with AI/ML engineering stakeholders on data schemas, prompts, and evaluation metrics. - Support content safety labeling and policy-aligned decisions for safety-critical datasets. Qualifications: - Professional experience in AI data annotation, data labeling operations, or model evaluation programs. - Strong command of annotation guidelines compliance, sampling methods, and training data quality audits. - Familiarity with RLHF, prompt evaluation, and large language model evaluation workflows. - Exposure to NLP concepts such as named entity recognition and classification taxonomies. - Ability to document decisions clearly and maintain traceability for dataset changes. Nice to Have: - Experience with computer vision annotation QA and multimodal dataset review. - Prior work with annotation vendors, BPO teams, or distributed labeling operations. - Understanding of content safety labeling, policy mapping, and risk-based QA.

How This Role Supports AI/ML Training Pipelines

Senior AI data annotation roles connect labeling output to measurable model outcomes. Your work improves training data quality through rubric design, annotation guidelines compliance, and QA evaluation loops. You may contribute to RLHF pipelines by validating preference labels, performing prompt evaluation, and calibrating scoring standards for large language model evaluation. In NLP, tasks often include named entity recognition, intent classification, and taxonomy maintenance. In computer vision annotation, you may review bounding boxes, segmentation masks, and dataset consistency. Content safety labeling and policy alignment help reduce harmful outputs and support safe deployment.

Work Environment and Remote Collaboration

These are remote full-time roles listed on Rex.zone and open to Portland-area candidates seeking remote work. You will collaborate asynchronously with cross-functional partners across AI labs, tech startups, and annotation vendors. Expect structured QA processes, versioned guidelines, calibration sessions, and periodic audits to ensure dataset integrity. The role emphasizes consistency, decision logging, and operational excellence in distributed data labeling workflows.

Who Should Apply

This page targets experienced professionals searching for senior AI data annotation jobs in Portland with remote full-time options. If you have led complex labeling projects, handled edge-case adjudication, contributed to RLHF or prompt evaluation, or built QA evaluation processes that improve training data quality, your background aligns. Experience across NLP, computer vision annotation, and content safety labeling is relevant, especially when paired with strong documentation and metric-driven quality management.

Related Job Modifiers and Pathways

Rex.zone roles may align with common search modifiers including remote, full-time, contract, freelance, entry-level, and senior depending on the listing. Domain pathways include NLP (named entity recognition, text classification), computer vision annotation (detection, segmentation), content safety labeling (policy mapping, risk categories), and LLM training pipelines (RLHF, prompt evaluation, QA evaluation). Employer contexts can include AI labs, technology startups, BPO teams, and specialized annotation vendors supporting enterprise AI programs.

How to Get Started on Rex.zone

Review the job details, confirm Remote Type is Remote, and ensure your skills match AI data annotation, data labeling, RLHF, and QA evaluation requirements. Prepare examples of guideline improvements, calibration outcomes, and audit results that demonstrate training data quality impact. Use Rex.zone to explore related roles in LLM evaluation, content safety labeling, NLP annotation, and computer vision annotation QA.

Frequently Asked Questions

  • Q: What does a senior AI data annotation specialist do day to day?

    Senior AI data annotation specialists manage training data quality through annotation guidelines compliance, QA evaluation, and edge-case adjudication. Day-to-day work can include RLHF preference ranking, prompt evaluation, large language model evaluation, dataset audits, calibration sessions, and documentation that supports reproducible labeling decisions.

  • Q: Are these senior AI data annotation jobs in Portland remote?

    Yes. The roles on this page are explicitly marked Remote Type: Remote while aligning to Portland-based candidates searching for senior AI data annotation jobs in Portland.

  • Q: Which domains are most common for senior annotation work?

    Common domains include NLP (named entity recognition, classification), computer vision annotation (boxes, segmentation, keypoints), content safety labeling, and LLM training pipelines such as RLHF and prompt evaluation.

  • Q: How is quality measured in data labeling and evaluation programs?

    Quality is measured using gold sets, inter-annotator agreement, rubric adherence, error taxonomies, sampling plans, and downstream model performance improvement indicators tied to training data quality.

  • Q: What types of employers use Rex.zone for these roles?

    Employers can include AI labs, tech startups, enterprise AI teams, BPO operations, and specialized annotation vendors running large-scale data labeling and QA evaluation programs.

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