Tool Use / Function Calling Engineer.
San Francisco.
$250,000
median salary, 35% above the national average
$186,000 to $327,000. Updated for 2026.
The numbers.
Everything you need to negotiate with confidence.
A Tool Use / Function Calling Engineer in San Francisco earns a median of $250,000 in 2026. That is 35% above the national average. The range runs from $186,000 to $327,000, and where you land depends on your experience, your skills, and how well you negotiate. Compensation scales with the complexity and reliability of tool integration systems built.
Salary range
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How San Francisco compares
San Francisco, CA
$250,000
Cost of living: 35% above average
National Average
$185,000
San Francisco is $65,000 above
What you should know
Here is what the Tool Use / Function Calling Engineer market actually looks like in San Francisco. San Francisco is the epicenter of venture capital and startup innovation, consistently producing the highest tech salaries in the nation. The city's concentration of AI labs, SaaS companies, and fintech firms creates intense competition for talent. Despite remote work trends, SF still commands the steepest salary premiums for engineering and product roles. Compensation scales with the complexity and reliability of tool integration systems built. Engineers who can design robust function calling frameworks with error recovery and multi-step planning earn premiums. Experience with multiple LLM providers and enterprise API ecosystems drives salaries 10% to 18% above median.
Junior tool integration engineers start near $138,000 building basic function schemas. Mid-level engineers designing robust multi-tool orchestration earn $183,000 to $210,000. Principal engineers architecting enterprise tool-use platforms reach $242,000 to $290,000. In San Francisco, those numbers run higher. The cost of living here is 35% above average, and employers adjust to compete.
Base salary is not the full picture. Equity at AI platform companies is a significant compensation component. Performance bonuses of 12% to 18% are standard, with some roles offering developer ecosystem growth bonuses tied to platform adoption metrics. And on the tax side: california's top marginal state income tax rate is 13.3%, the highest in the U.S. San Francisco has no additional city income tax, but overall tax burden remains steep. When someone quotes you $250,000, ask what the total package looks like. The gap between base and total comp is where real money hides.
On negotiation: Leverage competing offers aggressively. SF employers expect candidates to shop around, and matching or beating a rival offer is standard practice here. The range for Tool Use / Function Calling Engineers in San Francisco runs from $186,000 to $327,000. That is not a narrow window. Where you land inside it depends almost entirely on whether you negotiate and how well you prepare.
Top industries in San Francisco
Negotiating in San Francisco
Leverage competing offers aggressively. SF employers expect candidates to shop around, and matching or beating a rival offer is standard practice here.