Senior Ruby on Rails Engineer (AI Enablement) at Coatí | Torre

Senior Ruby on Rails Engineer (AI Enablement)

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Full-time

Legal agreement: Contractor

Currency exchange and payroll taxes to be paid by:

Candidate

Compensation
USD25 - 40/hour
Negotiable
location_on
Remote (for México residents)
Remote (for Colombia residents)
Remote (for Brasil residents)
Remote (for Argentina residents)
Posted 2 months ago

Responsibilities


Rails Platform Engineering: - Build and ship product features across a Ruby on Rails backend hosted on Heroku and two React applications hosted on Vercel. - Work within a mature, layered monolith that supports a real-world physical operation, including state machines, warehouse workflows, feature flags, device records, and third-party integrations. - Improve the architecture incrementally while supporting a roadmap of new products and operational capabilities. - Balance AI development with the reliability, maintainability, and performance expectations of the core Rails platform. - Contribute across the full development lifecycle, including implementation, testing, deployment, production support, and observability. AI Platform, Evaluation, and Guardrails: - Build the shared AI infrastructure used across product features and internal engineering workflows. - Create evaluation harnesses that measure model performance against real company data and known outcomes before changes reach production. - Establish guardrails for model inputs, outputs, tool use, confidence thresholds, and human escalation. - Design AI systems that fail safely when data is incomplete, ambiguous, or inconsistent. - Track model behavior in production and turn human corrections, overrides, and exceptions into measurable feedback. - Define shared grading and evaluation standards so different AI-enabled features are assessed consistently. - Help the company maintain control over its AI systems as they move from prototypes into operational workflows. Device Data, Serial Numbers, and Grading: - Build workflows that use serial numbers and other device identifiers to retrieve and enrich device information. - Connect internal device records with trusted external or proprietary data sources while preserving traceability and data quality. - Normalize inconsistent device information collected from customers, warehouses, integrations, and historical records. - Develop systems that classify or grade devices using the company’s A–D rating framework. - Train, fine-tune, or otherwise adapt models using the company’s historical dataset when that provides a measurable advantage over prompting or retrieval alone. - Design confidence scoring and review workflows for cases where an identifier cannot be reliably resolved. - Protect inventory workflows from small but consequential errors, such as confusing the letter “O” with the number “0” in a serial number. AI-Assisted Customer Support: - Build triage and classification systems that automatically route incoming customer requests. - Implement semantic deduplication so recurring questions can be answered from established precedent rather than repeatedly reaching a person. - Ground suggested responses in answers the company has previously reviewed and provided. - Automatically create Linear issues when a support request is determined to be a product defect, including the relevant customer and technical context. - Design clear escalation paths to human operators and measure how frequently and why escalation occurs. - Ensure AI-generated responses are auditable, appropriately sourced, and easy for a person to review. Retrieval and Reasoning from Historical Data: - Move AI systems from relying only on static rubrics toward reasoning from relevant historical precedent. - Build retrieval workflows over years of data involving devices, grades, processing decisions, and resale outcomes. - Determine when relational queries, search, embeddings, or other retrieval techniques are appropriate. - Make pragmatic infrastructure decisions based on the problem rather than introducing technologies by default. - Evaluate whether retrieved examples meaningfully improve model accuracy and decision quality. Agents That Act: - Build controlled agents capable of performing actions within the company’s domain, such as looking up a device, checking a shipment, updating a record, or drafting a customer update. - Define which actions can run automatically and which require explicit human approval. - Implement authorization, validation, audit logging, rollback strategies, and operational safeguards. - Prevent agents from taking actions outside their intended scope. - Extend agent-based workflows into engineering tasks where appropriate, including code generation, test creation, change suggestions, and code review. AI-Enabled Development Workflows: - Identify practical opportunities to use AI throughout software development, QA, and DevOps. - Improve how engineers use AI for implementation, debugging, test generation, documentation, incident investigation, and code review. - Develop shared workflows and reusable context so engineers do not repeatedly solve the same prompting or tooling problems in isolation. - Evaluate AI-assisted engineering tools based on measurable improvements in quality, speed, or reliability. - Ensure AI-generated code and infrastructure changes follow the same review, testing, and security standards as human-written work. - Help engineers build confidence in AI tools without encouraging uncritical reliance on them. AI Adoption and Team Enablement: - Help the organization adopt AI through practical delivery rather than presentations or isolated experiments. - Work consultatively with engineers, product leaders, and operational teams to identify appropriate AI use cases. - Address understandable hesitation by making model behavior visible, measurable, and controllable. - Explain the limitations and tradeoffs of proposed AI systems to technical and nontechnical stakeholders. - Make AI fluency a shared team capability rather than knowledge concentrated in one person. - Establish patterns, documentation, and examples that other engineers can follow. - Raise the engineering standard by demonstrating disciplined, production-oriented AI development. Required Experience: - 5+ years of production Ruby on Rails experience, including significant experience working within a large, layered monolithic application. - Deep Rails knowledge and a track record of being the engineer others rely on for difficult framework, architecture, and production issues. - Hands-on experience shipping LLM or machine-learning features to production. - Experience with several applied AI patterns, such as retrieval, structured outputs, multimodal models, classification, tool use, agents, or model adaptation. - Experience building evaluation harnesses for AI systems, not only implementing AI-powered features. - Experience designing guardrails, confidence thresholds, human-review workflows, and safe failure modes. - Experience working with inconsistent or incomplete datasets, including normalization, entity resolution, or classification. - Sound judgment about when prompting, retrieval, fine-tuning, traditional software, or a non-AI solution is most appropriate. - Demonstrated ability to identify situations where AI should not be used. - Comfort working across the stack, including enough React experience to test, troubleshoot, and complete work in the company’s frontend applications. - Familiarity with production deployment, observability, testing, and operational support. - At least 75% overlap with Eastern Time. Valuable Additional Experience: - Experience training, fine-tuning, or adapting models using proprietary company datasets. - Experience building systems involving serial numbers, product catalogs, hardware identifiers, asset data, or entity matching. - Experience with AI-assisted QA, DevOps, code review, or software-development workflows. - Experience integrating LLMs with internal tools, APIs, databases, or transactional systems. - Experience operating AI systems where errors can affect inventory, logistics, financial outcomes, or physical operations. - Experience introducing AI capabilities into an organization that is still developing its adoption strategy. Professional Attributes: - You are an engineer first and prefer shipping working software over producing theoretical AI strategies. - You default to measurement. - You understand that a convincing demonstration is not the same as a reliable production system. - You know when to say no to AI and can explain why a deterministic or human-driven solution would be safer or more effective. - You are pragmatic about infrastructure and prefer using the existing stack before introducing new services or databases. - You are comfortable moving between Rails product development, AI experimentation, data analysis, and production operations. - You think carefully about data quality, edge cases, ambiguity, and failure modes. - You are happiest with your hands on the keyboard. - You are comfortable in a Rails console, willing to read gem source when documentation falls short, and experienced enough with production systems to know where failures tend to hide. - You can work consultatively with stakeholders who may be uncertain or cautious about adopting AI. - You are comfortable being the most knowledgeable person on a topic without needing to be the loudest person in the room. - You raise the capabilities of the people around you through examples, shared tools, documentation, and thoughtful technical leadership.