Open-Source AI Engineer | Stability AI Global Negotiation Guide

Negotiation DNA: Startup Comp with UK Base + Pre-IPO Equity | $1B+ Valuation | London HQ | SIGNATURE ROLE | +15-30% ML PREMIUM | Open-Source AI Pioneer

Region	Base Salary	Equity (Pre-IPO/4yr)	Bonus	Total Comp
London	£105K-£170K	£80K-£260K	—	£125K-£235K
San Francisco	$195K-$275K	$100K-$325K	—	$220K-$356K
Remote US	$176K-$248K	$90K-$293K	—	$198K-$321K

Negotiation DNA The Open-Source AI Engineer is Stability AI's signature role — the position that defines Stability's mission of making powerful AI accessible to everyone. You will build and release open-source generative AI models: Stable Diffusion, Stable Video, Stable Audio, and the next generation of open models that compete with closed-source alternatives from OpenAI and Google. This role requires deep understanding of diffusion model architectures, training at scale, model compression for consumer hardware, and the unique engineering challenges of building models that must work well across an enormous diversity of deployments — from cloud GPUs to consumer laptops. The +15-30% ML Premium reflects the extreme demand for engineers who can build state-of-the-art generative models for open release.

Level Mapping: Stability AI Open-Source AI Engineer = Google L5-L6 Research Engineer = Meta FAIR Research Engineer IC5-IC6 = Hugging Face Senior ML Engineer

The Open-Source Mission Premium Stability AI's open-source approach is a genuine competitive advantage in recruiting. Many top ML engineers want to build AI that's accessible to everyone, not locked behind proprietary APIs. Use mission alignment in negotiations, but don't let it suppress compensation: "I'm choosing Stability because I believe open-source AI is critical for the future. That mission alignment is genuine — but I also need compensation that reflects the market rate for engineers who can push the state of the art in generative models." Stability's London HQ means many roles are UK-based, where base salaries are lower in absolute terms — but the equity and total comp should be competitive with US AI startups when adjusted for market.

Global Levers

1. Signature Role Scarcity: "Open-source model development requires a rare combination of skills — state-of-the-art research, production engineering, model optimization for diverse hardware, and community engagement. I bring that full stack: £165K base and £250K equity/4yr."
2. Open-Source Community Impact: "My open-source releases will be used by millions of developers and researchers worldwide. That community impact and ecosystem development is worth more than proprietary work — it drives Stability's brand and adoption: £160K base."
3. Competing Offers from Closed-Source Labs: "OpenAI is offering me $280K base / $600K equity and Meta FAIR is at $260K / $500K RSU for similar research work. I prefer Stability's open-source mission, but the comp gap is significant. For London: £165K base and £255K equity/4yr. For US-remote: $270K base and $315K equity/4yr."
4. US vs UK Comp Parity: "If I'm working remotely from the US for Stability, I need US-market compensation. Open-source AI engineers at my level command $250K+ base in the US market: $265K base."
5. Model Optimization for Consumer Hardware: "My expertise in model compression and optimization for consumer GPUs is critical for Stability's open-source strategy — models must run on consumer hardware to fulfill the accessibility mission. That optimization expertise is rare: £165K base."

Negotiate Up Strategy: "I'm an ML engineer deeply committed to open-source AI — I've contributed to [open-source model / framework] and believe accessible AI is essential for the future. I'm holding an OpenAI offer at $280K / $600K equity and a Meta FAIR offer at $260K / $500K RSU. Stability's open-source mission is where I want to dedicate my career. For London: £165K base and £250K equity/4yr with a £30K signing bonus. For US-remote: $270K base and $310K equity/4yr with a $50K signing bonus. The ML Premium applies — generative model expertise is in extraordinary demand. My floor for London is £140K; for US-remote, $240K."

Evidence & Sources

• Levels.fyi AI startup and UK tech compensation data (2025-2026)
• Glassdoor Stability AI salary reports
• Blind verified Stability AI offer threads and UK ML engineer market data
• Stability AI careers page and open-source model release history