Monday Intel N°6: What a senior AI backend engineer costs in SF.

Every Monday we publish one honest observation about hiring. This week it is the number founders ask us for most: what a senior AI backend engineer in San Francisco gets paid. We read 33 live job postings for senior backend, platform and inference engineers who build LLM product infrastructure, and recorded the base salary range each one publishes.

The headline numbers

• Confirmed Seed to Series B startups (19 postings): median posted range $180K to $250K, median midpoint $216K. The middle half of the market sits between $202.5K and $237.5K.
• Seed and Series A only (10 postings): median midpoint about $214K, middle half $200K to $233.8K.
• Series B only (9 postings): median midpoint $227.5K, middle half $210K to $240K.
• Later-stage and large AI companies (12 postings): median posted range $200K to $312.5K, median midpoint $262.5K.
• All 33 postings: median midpoint $235K, with posted ranges running from $120K to $500K.

A midpoint is the posted minimum plus the posted maximum, divided by two. The middle half is the 25th to 75th percentile of those midpoints. Ranges are wide: the median startup range spans $90K and the median later-stage range spans $135K, so where an offer lands inside a range depends on level and negotiation.

What it means for a Seed or Series A offer

• A strong senior engineer who has shipped LLM features to production: about $200K to $230K base.
• A proven inference, serving or distributed systems specialist: stretch to about $240K to $260K. That is where you compete directly with later-stage AI companies for the same people.
• Below $172.5K base, you are under the median posted minimum of every segment we measured. Expect to lose most senior candidates who hold a later-stage offer.
• Series B companies post about $10K to $15K more than Seed and Series A peers at the midpoint.

Size the gap in dollars

Later-stage companies post roughly $35K to $50K more in base at the midpoint. If you offer $220K and the candidate's alternative centers near $262.5K, you are about $42.5K a year short, or about $170K over a typical four-year vest. Your equity story has to credibly beat that, at a valuation you can defend.

Equity is common but rarely quantified. 28 of the 33 postings mention equity, and only 5 publish a number. The three seed-stage postings that publish a percentage range from 0.1% to 1.5%. Sharing a real number early builds trust and shortens negotiation.

Do not try to match the top of a later-stage range. Compete on scope, speed and ownership, and explain the equity with real numbers.

How we measured

Methodology: public posted base ranges only, not total compensation. Every figure is a base salary range published on a company's own job posting (Ashby, Greenhouse or Y Combinator job pages), and each posting was opened live on October 25, 2026. California's pay transparency law (SB 1162) is the main reason these ranges are public. Ranges exclude equity, bonus, sign-on and benefits. We used one posting per company, San Francisco, SF-hybrid or Bay Area roles only, and a cited public source for each company's stage. A few postings publish one range across several cities, so not every range is SF-specific. No self-reported or paid salary datasets were used. With 33 postings, this is directional, not exhaustive.

Get this for your role

This issue draws on our sample benchmark. A standard report is $500: one role in one city, benchmarked against live public postings you can click and check, with peer-set medians, P25 to P75 bands and plain-English offer guidance. A custom report is $900: a custom peer set built around the companies you actually compete with for candidates, 30+ verified postings, a review of your draft offer letter and a 30-minute call to pressure-test the offer before it goes out. To request either, email diego@nxteng.org or use the contact options on this page.

Sources

• StackAI, Senior Software Engineer, Engine & Distributed Systems (Series A), $202K to $230K SF/NYC tier, checked Oct 25, 2026: jobs.ashbyhq.com/stack-ai/963be320-fecb-4095-b73c-a9050b3188f5
• Mintlify, Senior Backend Engineer (Series B), $190K to $265K, checked Oct 25, 2026: jobs.ashbyhq.com/mintlify/7df478a7-8116-48cf-8e51-70176ca36f6e
• LangChain, Senior Backend Software Engineer, AI Observability & Evals Platform (Series B), $180K to $240K, checked Oct 25, 2026: jobs.ashbyhq.com/langchain/f07c1416-f126-4925-8606-5dd7c5a90f6f
• Firecrawl, Backend Infrastructure Engineer (Series B), $235K to $260K SF tier, checked Oct 25, 2026: jobs.ashbyhq.com/firecrawl/6840bbee-aae5-4846-97a2-ec2e764ee75b
• Together AI, Senior Backend Engineer, Inference Platform (Series C), $200K to $290K US range, checked Oct 25, 2026: job-boards.greenhouse.io/togetherai/jobs/4835763007
• Notion, Software Engineer, Model Capabilities, $255K to $300K SF or NYC, checked Oct 25, 2026: jobs.ashbyhq.com/notion/ab383335-1dd5-4d6a-971f-439cebf48a9d