Tool Use / Function Calling Engineer Salary.
Across 81 U.S. cities.
$133,000
national median salary
$103,000 to $169,000. Last updated July 2026.
Highest Paying
$185,000
San Jose, CA
Best Purchasing Power
$139,000
Richmond, VA
Lowest Paying
$102,000
Charleston, WV
Salary data sourced from Bureau of Labor Statistics Occupational Employment and Wage Statistics, H-1B Labor Condition Applications (DOL), state pay-transparency job postings, and community submissions. Most ranges are anchored to BLS OES occupation wage percentiles and placed by seniority level (entry near the 25th, mid at the median, senior at the 75th); a minority of emerging roles retain a modeled estimate where BLS has no matching series. Cost-of-living adjustments use Bureau of Economic Analysis Regional Price Parities (2025 index). Last updated July 2026. Baseline derived from BLS SOC 15-1252. Full methodology.
The average Tool Use / Function Calling Engineer salary in the United States is $133,000 in 2026, with the full range spanning $103,000 at the 25th percentile to $169,000 at the 75th. San Jose pays the most at $185,000, while Richmond offers the best purchasing power after cost-of-living adjustments. Compensation scales with the complexity and reliability of tool integration systems built.
Tool Use / Function Calling Engineer salary by city.
Skills that increase Tool Use / Function Calling Engineer pay.
The skills below command measurable salary premiums for Tool Use / Function Calling Engineers based on job posting data. Learning the top skill here could add $18,620 to your annual compensation.
≈ +$18,620 per year
≈ +$17,290 per year
≈ +$15,960 per year
≈ +$14,630 per year
≈ +$14,630 per year
≈ +$13,300 per year
≈ +$13,300 per year
≈ +$11,970 per year
What you should know.
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.
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.
Total compensation breakdown.
Salary by company size
Remote salary adjustment
Remote Tool Use / Function Calling Engineers typically earn $120,000 (10% less than on-site). This reflects location-adjusted pay policies at companies using geographic salary bands. Some companies pay flat national rates regardless of location.
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Common questions about Tool Use / Function Calling Engineer pay.
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