Hiring a Senior Dev Full-Time vs. on Contract at $210/day: The 12-Month Math

A senior dev on a permanent contract in Paris costs between 82,000 and 95,000 euros a year in employer payroll taxes alone. Add recruiting, onboarding, equipment, and the bill tops 100,000 euros before they've merged their first PR. On contract at $210/day, the annual budget drops below 40,000 euros, with someone operational from week one. I ran the math line by line over 12 months to settle this once and for all.

What a senior dev on a permanent contract really costs

Why does gross salary only account for 60% of the bill?

When a founder tells me "I'm hiring a senior dev at 58,000 euros gross," I know they're underestimating the real cost by at least 40%. Gross salary is just the visible part of the iceberg.

Employer payroll taxes in France run around 42 to 45% of gross. On a salary of 58,000 euros (the Paris region median for a profile with 5 to 8 years of experience, source APEC Q1 2026), that means an employer cost of 82,000 to 84,000 euros a year. Add mandatory health insurance, disability coverage, meal vouchers: you're at 85,000 euros before you've even posted the job ad.

Recruiting itself weighs heavily. A headhunting firm charges between 15 and 20% of the annual gross salary, meaning 8,700 to 11,600 euros for this profile. According to APEC, the average time to recruit a tech manager in 2025 exceeds 11 weeks in the Paris region. During those three months, your project runs at half speed or doesn't start at all.

How much does the onboarding nobody ever budgets for actually cost?

A senior dev takes 2 to 3 months on average to reach cruising velocity on a new project. During that phase, their productivity runs at 40 to 60% of nominal capacity. Over 3 months for a profile costing 85,000 euros a year, that's a hidden cost of 7,000 to 10,000 euros in lost productivity.

Add equipment (laptop, monitors, JetBrains or GitHub Enterprise licenses) for around 3,000 euros. And the line item nobody budgets for: management time. A freshly hired dev pulls 5 to 8 hours a week from their tech lead or CTO during the first two months.

Year-one tally for a full-time senior dev in Paris: between 95,000 and 110,000 euros all-in. That figure is nothing unusual. According to the Syntec Numerique benchmark, the fully loaded cost of an experienced engineer at a French IT services firm has exceeded 90,000 euros since 2025, before margin.

$210/day on contract: the real 12-month budget

How does the annual bill break down?

The math fits on one line. France has roughly 218 working days per year. At $210 per day, that comes to $45,780 over 12 months.

At Extra Dev that figure includes everything: a developer with at least 8 years of experience, AI tooling (Claude Code, Cursor, GitHub Copilot), project coordination, and technical supervision. No employer payroll taxes to pay, no health insurance, no paid leave to fund. The bill matches the exact number of days worked.

To place that rate in the market: according to Sitenco, a senior dev on a remote contract bills from 250€ per day in France for 6 years of experience. Expert profiles climb to 600 or even 700€ according to Kicklox. The average daily rate observed for a senior full-stack profile in 2025 hovers around 450€.

$210/day for at least 8 years of experience is a third of the French market rate.

The gap comes down to two combined levers: a team based in Vietnam (lower cost of living, a solid tech talent pool trained on modern stacks) and systematic AI augmentation that multiplies each profile's throughput. This isn't low-cost: it's a different production model.

The numbers compared over 12 months

Which cost lines disappear when you switch to contract?

The table below puts the two columns side by side. I took a senior dev at 58,000 euros gross on a permanent contract (APEC 2025 median, Paris region) and a contract profile at $210/day over 218 working days.

The delta is massive: roughly 60% of the cost stripped out in year one. Even in year two, when the permanent contract no longer carries recruiting or onboarding costs, the gap stays well above 45,000 euros.

One CTO objected that the permanent hire "works out cheaper per hour over 3 years." I reran the math: over 36 months, the full-time hire piles up roughly 260,000 euros all-in. The contract at $210/day over the same period: about $137,000. The gap never closes. It widens, because the permanent salary's annual raises (+3 to 5% per year) inflate the cost every year, while the contract daily rate stays contractually fixed.

What the spreadsheet doesn't capture

Why does time-to-first-commit change the equation?

A permanent hire takes 11 weeks to recruit, then 2 to 3 months to ramp up. First meaningful commit in production: month 4 or 5. On contract at Extra Dev, the first profile arrives within 48 hours and starts in under 7 days. First commit: week 1.

On a project with a 6-month deadline, that difference is worth 3 to 4 extra months of velocity. It's often the line between an MVP shipped on time and a late project burning cash with nothing to show investors.

How does an AI-augmented dev change the value-for-money equation?

A classic senior dev merges 8 to 12 PRs per week on average on a standard web project (Next.js, React, Python API). Our profiles, equipped with Claude Code, Cursor and Copilot, hit 15 to 22 PRs per week on comparable scopes. UVIK's video on staff augmentation in 2026 confirms the trend: partners who validate their developers' command of AI tools deliver measurably higher velocity.

It's not magic. It's an industrialized process: specs broken into short, testable blocks, precise acceptance criteria per block, an agent that reads the project context (CLAUDE.md, ARCHITECTURE.md), executes the task, tests in the browser, documents it, then moves to the next block. I built this system on my own SaaS projects before deploying it on client work.

The concrete result: an AI-augmented dev on contract at $210/day produces the equivalent of a full-time profile billed at 450 to 500€ a day in employer cost. The combination of a senior Vietnam dev + AI + strict process outperforms most traditional teams on raw velocity.

"The real advantage isn't AI on its own. It's the industrialized software production system built around AI, with clear specs, reliable agents, and human quality control at every merge."

Vincent Roye, June 2026

When a permanent hire is still the right call

Should you hire if the project runs past 24 months?

Contract isn't the universal answer. Three situations still justify a permanent hire for a senior dev.

Sensitive intellectual property. If your core business rests on a proprietary algorithm or critical confidential data, an employee bound by a non-compete clause and a reinforced confidentiality agreement offers stronger legal protection than a contractor.

Long-term team culture. When you're building a product team of more than 10 people and 3-year cohesion is a strategic stake, a permanent hire allows deeper identity-level integration. Contract works as reinforcement, autonomous on a defined scope, rarely as the cultural backbone of a squad.

Ultra-specialized profiles unavailable on contract. Some niche expertise (Linux kernel, compilers, critical embedded systems, low-level cryptography) is scarce on the contract market. A permanent hire is sometimes the only way to lock down those skills.

Outside those three cases, the metrics speak for themselves. Contract wins on cost, velocity, scaling flexibility, and the ability to start fast without a long commitment.

My verdict on the 12-month math

I've worked with founders torn between hiring their first senior dev and bringing one on contract. In 80% of cases, contract at $210/day was the right call for the first 12 months.

The reason comes down to three points: you pay for delivered code (not onboarding), you keep the flexibility to scale up or down without a layoff procedure, and with an AI-augmented dev, the productivity-per-dollar ratio has no equivalent on the French market in 2026.

My concrete advice: if your need runs under 24 months, or if you're not sure of the exact scope, start with contract. Run a 3-month test. Measure the PRs delivered, the code quality, the deadline adherence. You can always hire later, with a product that's already running and a clear picture of the profile you need in-house.

The 12-month math doesn't lie: under 40k against 100k euros, first commit in week 1 versus month 5.