Tool Use / Function Calling Engineer.
San Antonio.
$167,000
median salary, 10% below the national average
$124,000 to $218,000. Last updated April 2026.
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Data points to own the conversation.
If you are evaluating a Tool Use / Function Calling Engineer offer in San Antonio, TX, here is the reality: $124,000 to $218,000, with $167,000 as the midpoint. 10% below the national average. Compensation scales with the complexity and reliability of tool integration systems built. Do not accept the first number.
Salary range
Where do you fall?
Salary by experience
The gap between entry and lead level is typically $150,000. Where you land depends on years of experience and what you bring to the table.
Entry (0-2 yrs)
$109,000
to $134,000
Mid (3-5 yrs)
$142,000
to $175,000
Senior (6-9 yrs)
$184,000
to $217,000
Lead (10+ yrs)
$209,000
to $259,000
Salary trend
+7% YoYTotal compensation
Base salary is not the full picture. Equity, bonus, and signing can add $39,000 to the total package.
Base
$167,000
Equity
$22,000
Bonus
$14,000
Signing
$3,000
Estimated total: $206,000
How San Antonio compares
San Antonio, TX
$167,000
Cost of living: 9% below average
National Average
$185,000
San Antonio is $18,000 below
Tool Use / Function Calling Engineer salary by city
Salary by role in San Antonio
What you should know
The Tool Use / Function Calling Engineer landscape in San Antonio is not what most salary sites will tell you. San Antonio has a major military presence with Joint Base San Antonio and a growing cybersecurity hub. The city is home to USAA headquarters and a cluster of healthcare systems. The extremely affordable cost of living and no state income tax make it attractive for professionals seeking purchasing power. 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 Antonio, cost of living sits near the national average, so the numbers you see are roughly what you keep.
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: texas has no state income tax. San Antonio has no city income tax. The zero tax environment and very affordable housing create exceptional purchasing power relative to most metros. When someone quotes you $167,000, ask what the total package looks like. The gap between base and total comp is where real money hides.
On negotiation: Leverage the cybersecurity corridor. San Antonio's NSA facility and military cyber operations drive demand for cleared security professionals at premium rates. The range for Tool Use / Function Calling Engineers in San Antonio runs from $124,000 to $218,000. That is not a narrow window. Where you land inside it depends almost entirely on whether you negotiate and how well you prepare.
Sources: SEC filings, H-1B LCA (DOL), BLS OES, 50+ job posting platforms. COL: BEA Regional Price Parities (2025). Data verified by Justin Bartak, Founder & Chief AI Officer. Last verified April 8, 2026. Full methodology
Considering a related role?
- A AI Platform Engineer in San Antonio earns $166,000 (1% less)
- The highest-paying role in San Antonio is Distinguished Engineer at $303,000
Common questions.
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