Tool Use / Function Calling Engineer.
San Jose.
$255,000
median salary, 38% above the national average
$190,000 to $334,000. Updated for 2026.
The numbers.
Everything you need to negotiate with confidence.
Here is what Tool Use / Function Calling Engineers actually make in San Jose: $190,000 at the 25th percentile, $255,000 at the median, and $334,000 at the 75th. That is 38% above the national average. San Jose is the capital of Silicon Valley, home to Apple, Google, Adobe, and Cisco. The number on your offer letter will depend on what you bring and how you ask.
Salary range
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How San Jose compares
San Jose, CA
$255,000
Cost of living: 38% above average
National Average
$185,000
San Jose is $70,000 above
What you should know
Before you negotiate a Tool Use / Function Calling Engineer offer in San Jose, understand the terrain. San Jose is the capital of Silicon Valley, home to Apple, Google, Adobe, and Cisco. The city consistently ranks among the highest paying metros in the country for technology roles. Competition for talent is fierce, with employers offering aggressive compensation packages including equity, signing bonuses, and premium benefits to attract and retain engineers. 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 Jose, those numbers run higher. The cost of living here is 38% 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 13.3% state rate applies fully here. While gross salaries in San Jose are among the nation's highest, the tax burden means net pay may not stretch as far as expected. When someone quotes you $255,000, ask what the total package looks like. The gap between base and total comp is where real money hides.
On negotiation: Always negotiate equity alongside base salary. San Jose employers expect candidates to evaluate total compensation including RSUs, and leaving equity on the table is leaving money behind. The range for Tool Use / Function Calling Engineers in San Jose runs from $190,000 to $334,000. That is not a narrow window. Where you land inside it depends almost entirely on whether you negotiate and how well you prepare.
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Negotiating in San Jose
Always negotiate equity alongside base salary. San Jose employers expect candidates to evaluate total compensation including RSUs, and leaving equity on the table is leaving money behind.