David Espinoza Mendoza
Platform Engineer | DevOps / SRE | IT Infrastructure & SaaS Systems Builder
Profile
Platform and infrastructure engineer with hands-on experience across technical support, Linux/Windows server administration, hosting, virtualization, monitoring, troubleshooting, containers, automation, and SaaS platform engineering. I combine real production operations with a DevOps/SRE mindset, observability, technical documentation, and continuous improvement.
My profile brings together infrastructure administration, hosting operations, incident diagnostics, progressive container modernization, API integration, operational automation, and applied AI to build stable, maintainable, production-ready systems.
Professional value model
I design, implement, and operate technology solutions for companies that need stability, operational continuity, visibility, automation, and room to scale. My approach combines Linux/Windows infrastructure, hosting, networking, DNS, email, virtualization, containers, observability, APIs, and SaaS platforms to turn complex operational problems into manageable production systems.
- Operations and troubleshooting of production Linux/Windows infrastructure, hosting, DNS, email, and virtualization.
- Progressive modernization of services toward Docker, Docker Compose, Kubernetes/K3s, and cloud-native architecture.
- Design and operation of enterprise messaging SaaS platforms with APIs, webhooks, workers, queues, and observability.
- Incident diagnosis using logs, metrics, health checks, curl validation, monitoring, and service-level review.
- Operational automation through Bash, Python, Git, runbooks, technical documentation, and applied AI.
- Strong focus on stability, fault recovery, risk reduction, maintainable operations, and continuous improvement.
Areas of specialization
Linux/Windows Infrastructure and Hosting
Administration, support, and troubleshooting for Linux, AlmaLinux, Ubuntu Server, and Windows Server environments, including web services, DNS, email, databases, permissions, process management, and daily operations.
Containers and Platforms
Design and operation of services using Docker, Docker Compose, Kubernetes/K3s, Portainer, internal networks, persistent volumes, health checks, and production-oriented deployments.
Observability and Troubleshooting
Implementation and practical use of Grafana, Prometheus, Loki, Promtail, PMM, PRTG, and BitNinja for monitoring, metrics, logs, alerting, incident diagnosis, and operational continuity.
Messaging SaaS and APIs
Engineering enterprise messaging platforms with WhatsApp API, Chatwoot, Meta Graph API, OAuth, webhooks, PostgreSQL, Redis, BullMQ, worker services, and multi-instance architecture.
Networking, DNS, Email, and Operational Security
Operational management of Cloudflare, DNS, SSL/TLS, Plesk, cPanel/WHM, Postfix, Qmail, Exim, MailEnable, SpamTitan, SPF, DKIM, DMARC, firewalls, CSF, iptables, SSH, and Tailscale.
Automation and Applied AI
Automation of technical operations with Bash, Python, Git, runbooks, OpenAI API, Ollama, AI agents, BMA, Hermes, OpenClaw, and operational documentation.
Experience
DevOps / SRE Engineer & Platform Builder
Cyberfuel
- Administer Linux/AlmaLinux and Windows Server infrastructure while troubleshooting production incidents.
- Operate and support HTTPD, Nginx, Postfix, Qmail, MySQL, iptables/firewall, IIS, MSSQL, MailEnable, and SpamTitan services.
- Manage hosting operations, DNS, email infrastructure, SSL certificates, and websites with Plesk and cPanel/WHM.
- Support virtualization workloads on VMware vSphere, Proxmox, ESXi, vCenter, and enterprise platforms.
- Handle backups, restores, snapshots, and operational recovery with Veeam and related tooling.
- Monitor and diagnose systems through PRTG, BitNinja, PMM, Grafana, logs, metrics, and health checks.
- Manage DNS/IP assignments, propagation validation, record integrity checks, and domain support.
- Troubleshoot incidents across servers, networking, email, permissions, ports, databases, processes, and web services.
- Deploy and run internal services with Docker, Docker Compose, reverse proxies, and segmented internal networks.
- Produce technical documentation, escalate incidents appropriately, and drive operational improvement.
SaaS Platform Builder
Kore-CR / SaaS Infrastructure Lab
- Designed a multi-instance WhatsApp API platform aligned with enterprise SaaS requirements.
- Integrated the platform with Chatwoot to centralize conversations and messaging workflows.
- Built a QA/Admin Console for diagnostics, operational testing, service-state validation, and instance checks.
- Engineered a Social Gateway integrating Meta, Facebook, and Instagram via APIs, OAuth, webhooks, and worker services.
- Implemented messaging flows on PostgreSQL, Redis, BullMQ, workers, queues, webhooks, and durable persistence.
- Deployed services behind Traefik with TLS, public domains, internal network segmentation, and controlled exposure.
- Implemented observability with Grafana, Prometheus, Loki, Promtail, and explicit health-check pipelines.
- Automated technical operations, produced runbook-style documentation, and evolved architecture iteratively.
IT Solutions Technician / Field Infrastructure Support
Professional Service Espinoza
- Installed and supported WiFi networks, access points, structured cabling, and connectivity equipment.
- Implemented CCTV, alarm systems, IP setups, smart-home solutions, and on-site technology deployments.
- Delivered preventive and corrective maintenance for hardware, software, and operational devices.
- Diagnosed connectivity issues across networks, endpoints, printers, POS devices, and internal systems.
- Provided customer-facing field support, baseline documentation, and incident resolution.
Applied Infrastructure Practice
Critical Infrastructure and Transactional Platforms
- Analyzed SPOFs, bottlenecks, critical paths, latency patterns, concurrent load, and continuity risks.
- Evaluated stateful versus stateless workloads while planning progressive migration to containerized platforms.
- Diagnosed PHP process saturation, SMTP failures, bounce issues, IP reputation problems, DNS instability, and intermittent errors.
- Reviewed logs, metrics, alerts, health checks, permissions, ownership, ports, and service behavior under stress.
- Designed rollback strategies, backup policies, fault-recovery paths, and low-risk phased change execution.
Technical skills
Containers & Orchestration
Docker, Docker Compose, Kubernetes/K3s, Portainer, Longhorn, container networking, persistent volumes, health checks
Linux / Windows Server
Linux, AlmaLinux, Ubuntu Server, Rocky Linux, Windows Server, systemd, Linux services, baseline hardening, troubleshooting
Hosting & Edge
Plesk, cPanel/WHM, Cloudflare, DNS, SSL/TLS, Let's Encrypt, Traefik, Nginx, virtual hosts, reverse proxy
Email Infrastructure
Postfix, Qmail, Exim, MailEnable, SpamTitan, SPF, DKIM, DMARC, SMTP troubleshooting, bounce handling, IP reputation
Data & Queues
PostgreSQL, MySQL, MariaDB, Redis, BullMQ, jobs, workers, backups, migrations, connection troubleshooting
Observability
Grafana, Prometheus, Loki, Promtail, PMM, PRTG, BitNinja, metrics, logs, alerting, health checks
Virtualization & Backup
VMware vSphere, Proxmox, ESXi, vCenter, Veeam, snapshots, restores, backups, baseline disaster recovery
Networking / IT
Cisco CCNA, switching, routing, VLANs, wireless, access points, CCTV, POS devices, SSH, Tailscale, firewalls, CSF, iptables
Backend & APIs
Node.js, PHP, Laravel, REST APIs, webhooks, OAuth, Meta Graph API, Chatwoot integrations, WhatsApp API
Automation & AI
Bash, Python, Git, GitHub, runbooks, technical documentation, OpenAI API, Ollama, Hermes, OpenClaw, BMA, AI agents
Key achievements
- Designed and operated Docker Compose stacks for APIs, workers, databases, and internal services.
- Delivered Traefik-based service exposure with TLS, public domains, reverse proxy routing, and internal networks.
- Built a multi-instance WhatsApp API platform for enterprise SaaS operations.
- Integrated messaging infrastructure with Chatwoot to centralize customer conversations.
- Developed a QA/Admin Console for diagnostics, operational testing, and service validation.
- Engineered a Social Gateway for Meta, Facebook, and Instagram using OAuth, webhooks, workers, and outbound jobs.
- Implemented a PostgreSQL + Redis + BullMQ architecture with workers and queues for messaging workloads.
- Rolled out observability stacks with Grafana, Prometheus, Loki, Promtail, PMM, PRTG, and BitNinja.
- Resolved production issues across Linux/Windows systems, DNS, email, hosting, Plesk/cPanel, and container services.
- Solved SMTP deliverability problems including bounces, SPF, DKIM, DMARC, and IP reputation issues.
- Automated technical processes with Bash, Python, Git, runbooks, and AI-assisted operational flows.
- Modernized legacy services progressively into container-friendly, maintainable architectures.
- Built technical documentation and a public Knowledge Base as part of a professional operations portfolio.
Education & certifications
- VLA Academy — Linux Administrator
- Cisco Networking Academy — CCNA 200-301 / Networking
- VLA Academy — Telecommunications Technician / CCNA
- High School Diploma — Liceo de Villarreal
- English B2/B2+