Boris Petrov
Fractional senior frontend engineer
Over a decade at Amazon, Google, and startups. SF.
Areas of focus
Complex state modeling
State-heavy apps where the frontend carries real logic. Validation rules, async orchestration, cross-field dependencies – not just fetching and rendering. Bringing order and extensibility to that complexity.
Design feasibility and tradeoffs
Auditing designs for missing states, impossible interactions, patterns that won't survive real data. Finding the 80/20 between design fidelity and engineering cost.
AI workflow UX
Interfaces where AI generates content humans review and approve – soliciting suggestions, handling async generation, merging results into existing work.
Selected client work
Tempo AI
15 monthsAI-augmented video publishing platform- Second engineer hired — zero to early-access launch
- Multi-phase pipeline state: transcoding, AI generation, rendering, each with its own progress and failure modes
- Layered data fetching: server components, React Query caching, Supabase Realtime
- Cross-platform publish form: one view serving 8 platform types with per-platform validation and field constraints
- Design collaboration on AI-augmented workflows with few established patterns
California Pizza Kitchen
22 monthsNational restaurant chain website and ordering system- Led team of 3 across frontend, CMS, and backend
- Inherited and stabilized a codebase left broken by the previous agency
- CMS-powered menu pages replacing legacy PDFs, including individual item detail pages
- 100+ programmatically generated, SEO-optimized location pages
- Smart redirect preserving loyalty sessions across domains
- 25% homepage load time reduction; WCAG accessibility compliance
Navii
1 monthAI assistant for career development- Pre-launch stabilization of agent-built frontend
- Highest-impact fixes under tight deadline
- Guardrails for post-launch changes
Also worked with
Engineered Tax Services
Rising Stars AI
Lasso Labs
SpeakEasy
Subcity
Mirror
Some client work is under NDA or behind logins.
When teams bring me in
Inflection point
Approaching a launch, fundraise, or growth spike and need senior frontend to get it over the line.
Expertise gap
Need senior frontend expertise but not ready for a full-time hire.
Code bottleneck
Codebase is getting harder to change – fast prototyping, AI-generated code, or accumulated shortcuts.
Testimonials
“He brought a level of craft to everything he built… had a strong partnership with our designer, which made a huge difference in what we were able to ship… reliable as hell when it comes to hitting deadlines.”
Ravi Kolluri
Cofounder & CTO, Radical Tempo
“Boris’s super power is that he looks beyond the technical and grasps the business objective… It’s rare to find a technologist who can push and pull at a business level to deliver results in the form of revenue.”
David Harris
VP of Digital, California Pizza Kitchen
“He always goes above and beyond to assess the clients’ needs and flag any potential roadblocks early on… Boris excels as a team lead and manager, ensuring that the team is well-equipped for any project and capable of overcoming any challenge.”
Alexz Graves
Sr. Creative Producer, Planetary
“…a great problem solver… He presents his way as an option to consider and seeks input from others on pros and cons… He spends time trying to understand the problem and having empathy for the user.”
Ajoy Bhambani
Founder, Rising Stars AI
“I’ve worked with Boris on multiple occasions with different budget, timing, and expertise requirements, and every time, Boris has been able to deliver high quality work… His communication skills regarding estimates, technical tradeoffs, and user requirements are top notch.”
Molly Nacey
Fractional CTO/CPO
“…holds a very high bar for quality… has earned trust with the team as someone who can work independently with PMs, UX and TPMs to figure out the goals, requirements, risks and schedule for a project and then successfully execute.”
Chris Bee
Engineering Manager, ex-Amazon/Zillow/Uber