Engineering staffing agencies vs a senior network: How to choose, and what to check before you sign

Key takeaways

• An engineering staffing agency recruits engineers for your open roles and bills a markup on their pay. Choose one on six checks: who does the vetting and how deep, time to a working engineer, fit for your company's stage, where the engineers work from, replacement terms, and what's inside the all-in rate.
• IT contract markups usually run 35 to 50% above the engineer's pay rate, and the agency's profit margin is typically 3 to 8%, per KORE1's 2026 pricing guide. Most of the markup is payroll tax, insurance and recruiting cost, so ask what's inside it before you negotiate it.
• Hiring a contractor away from an agency usually costs 10 to 25% of projected first-year salary, often pro-rated down the longer they've worked for you. Get the schedule in writing before the first candidate call.
• A senior network vets its members before your role exists and matches from that bench. An agency recruits against your role. That one difference drives most of the six checks.
• Use an agency for permanent hires, high-volume mid-level roles and on-site work in one city. Use a senior network when the role needs senior judgment from the first week and you'd rather interview two people than twenty.

Why this question matters

You have an engineering role that can't wait for a full search, a budget line, and proposals from three engineering staffing agencies that read alike: profiles, an hourly rate, a start date. What separates them sits in the parts of the contract you haven't read yet, such as who screened the candidates, what happens when the first one misses and what it costs to hire the engineer at the end. This guide gives you six checks to run across every proposal, including the ones from senior networks that don't call themselves agencies, so you compare the terms you'll live with.

The frame: Three vendor types, six checks

Three kinds of vendor answer when you search for engineering staffing agencies, and they differ most in what happens before your role reaches them.

Large IT staffing firms, such as TEKsystems, Robert Half and Kforce, run national recruiting operations across many roles and industries. They place engineers on contract, contract-to-hire and permanent terms, employ the engineer during a contract, and are built for volume, payroll and compliance across many locations.

Specialist engineering agencies, such as KORE1 and Motion Recruitment, recruit technical roles only, usually with recruiters who know the stacks they hire for. Like the large firms, they open a search for each role you give them, present a short slate, and charge a markup on contract work and a fee on permanent placements.

Senior networks vet engineers into a standing membership before any client role exists, then match from that membership when you describe the work. Toptal works this way, and so does A.Team.

The six checks apply to all three. The table further down shows the answer each type tends to give, as a starting point for your own questions.

What is an engineering staffing agency?

An engineering staffing agency is a firm that recruits engineers for a client's open roles and either employs them on contract, billing the client an hourly rate that includes a markup, or places them as the client's own employees for a one-time fee. Most offer three arrangements: contract, contract-to-hire and direct hire. A software engineer staffing agency, or developer staffing agency, is the same model limited to software roles.

An engineering recruiting agency usually means the direct-hire half on its own: it finds candidates you employ and charges a placement fee, which KORE1's 2026 pricing guide puts at around 20% of first-year salary for most IT placements and 25 to 30% for senior and specialized roles. The same phrase also covers civil, mechanical and electrical engineering staffing. This guide is about software engineering, though most of the checks carry over.

If you're still choosing a model rather than a vendor, marketplaces vs agencies vs staffing firms compares them side by side. This guide starts once you have names on a shortlist.

How do you choose an engineering staffing agency? Six checks

Run six checks on every vendor, in writing: who does the vetting and how deep it goes, how long until an engineer is working in your codebase, whether the vendor fits your company's stage, which regions the engineers work from, what the contract says when a placement misses, and what the all-in rate contains. Write each vendor's answers in a column and read across.

A.Team sits in the senior-network column: six-stage vetting into a network of 11,000+ vetted builders with under 2% acceptance, builders across North America, Europe and Latin America, replacement with a builder of substantially similar experience and skills, and one all-in rate per builder on the service order.

Who does the vetting, and how deep does it go?

Vetting is only as good as the person who evaluates the code, so ask who that person is and what the candidate produced for them. A recruiter screen checks availability, rate, work authorization and résumé fit. Whether a senior engineer also reviews the candidate's work depends on the agency, and at a large firm it often depends on the desk.

Toptal publishes its own funnel, which makes it a useful reference for what a documented screen looks like. Its screening page lists five steps: a language and communication interview that 26.4% of applicants pass, skill assessments (7.4%), a live screening with domain experts (3.6%), a one-to-three-week test project (3.2%), and a continued-performance step, leaving fewer than 3% accepted. The full process takes three to eight weeks. You don't need a vendor to copy that. You need them to describe theirs as specifically, with what happens at each step, who runs it and how the pass rate is counted. How to read acceptance-rate claims explains why two vendors' percentages often divide by different things.

The quickest test on the call is to ask for the artifact. An anonymized scorecard or work sample from a recent candidate's screen tells you more than a description of the process, and a vendor that vets deeply will have one ready.

How long until an engineer is working in your codebase?

Ask for the median time from a signed order to an engineer's first billed day, because published speed claims count different events. Toptal's homepage says you can hire in under 48 hours, with an average time to match under 24 hours. KORE1 says its average time-to-hire for IT roles is 17 days. A.Team's standard is a working builder in about 2 weeks, sometimes sooner depending on scope. That's a match, a hire and a person working, three separate events, and none of them is the day the engineer's first pull request merges in your repository.

The structural difference sits under those numbers. An agency opens its search when you open the role, so its clock includes sourcing. A network starts from people it has already vetted, so its clock starts at matching. Both then wait on your interviews, your paperwork and your access provisioning, which are often the slowest part of the whole sequence. Ask each vendor what happened to the clock the last time the first candidate was wrong.

Does the vendor fit your company's stage?

Fit by stage comes down to who on your side will run the engineer. A seed-stage company with no engineering manager needs a vendor that carries continuity and escalation, because nobody on the buyer side will. A growth-stage company hiring several engineers a quarter toward permanent headcount gets real value from an agency's direct-hire desk and from contract-to-hire. An enterprise with procurement, an approved-vendor list and a contractor program needs a vendor that can clear the paperwork, and a large firm that's already on the list starts with an advantage there.

Choose for the management capacity you have today. A senior engineer placed into a team with no one to set priorities will set their own, which is sometimes exactly what you wanted and sometimes a quarter of work on the wrong thing.

Where do the engineers work from?

Ask for the regions each shortlisted person works from and the number of your core hours they share, in writing. "US-based" and a list of countries are sales answers. Overlap is the number that decides whether your standups, code reviews and incident calls work, and it belongs to the person, not the vendor's headquarters. A.Team's builders work across North America, Europe and Latin America, and the same test applies: check every name against your hours.

What happens when a placement misses?

Read the replacement terms before you need them. On contract work, the contract should say how fast a replacement arrives, who pays for the new engineer's ramp, whether the rate changes and how much notice either side gives. On direct hire, KORE1 notes that most agencies offer guarantee periods of 30 to 90 days, after which a departure is yours to absorb.

Continuity is the half buyers forget. Ask what happens when an engineer leaves mid-engagement for reasons that aren't performance, who writes the handover, and whether the vendor has a contact who stays with the engagement after the first month. SLA expectations when buying senior talent lists the terms worth asking for by name.

How much do engineering staffing agencies charge?

Most engineering staffing agencies charge a markup on the engineer's hourly pay, which KORE1 puts at usually 35 to 50% for IT work, plus a conversion fee if you hire the engineer and a placement fee for direct hire. The markup is mostly cost: payroll taxes, workers' comp insurance, benefits where offered and recruiting, with the agency's profit margin typically 3 to 8%.

Here's what that looks like over a year on an illustrative $100 hourly pay rate, assuming full-time hours.

Two things follow. The markup percentage on its own tells you little, because a 50% markup on a well-paid senior engineer can cost less per hour of useful work than 35% on a weaker one, so compare bill rates for comparable people. And because most of the markup is cost, the margin you can negotiate is narrower than the headline suggests. The question that pays is what's inside the bill rate.

The conversion fee is where buyers get surprised. KORE1 puts it at usually 10 to 25% of projected first-year salary, and many agencies pro-rate it down by time on contract; some credit the markup you've already paid against it. On an illustrative $180,000 salary, 10 to 25% is $18,000 to $45,000. Most vendors have a conversion term, senior networks included, so ask for the schedule in writing and how it changes month by month.

Senior networks usually quote one all-in rate per engineer with the platform's margin inside it, which moves the question from "what's your markup?" to "what does this rate include, and what does it cost to hire this person later?" A.Team quotes one all-in rate per builder on the service order, with no hidden tiers or success fees, under one MSA. Pricing questions to ask every vendor has ten questions that make any two quotes comparable.

When is a senior network the answer, and when is an agency?

An agency is the better answer when you're hiring permanent employees, since direct-hire search is a core part of what agencies do and a network's model is built around contract engagements. It's the better answer for several mid-level engineers at once on common stacks, for on-site work in one city, when you want the vendor to employ the engineer and carry payroll and compliance, and when your procurement team already has the agency on its approved list and the start date matters more than the seniority. It's also the answer for roles outside software.

A senior network is the better answer when the role needs senior judgment from the first week, such as a tech lead, an architect or an AI engineer joining a live system. It fits when you don't have the interview capacity to screen twenty candidates, when the term is uncertain or likely to change, when you want one rate you can read line by line, and when the hours you need cross regions.

Plenty of companies use both: an agency running the permanent pipeline and a senior network covering the senior contract capacity needed this quarter. If you're evaluating networks in particular, how to evaluate a talent marketplace runs a six-dimension framework that works for them too.

What to do next

Put the six checks on one page and send them to every vendor on your shortlist before the first call, then read the answers in columns. Ask for three things in writing up front: the bill rate and what's inside it, the conversion schedule, and the replacement terms. If a vendor needs a second call to answer any of the three, ask why.

A.Team matches senior engineers from 11,000+ vetted builders with under 2% acceptance, with a working builder in about 2 weeks, sometimes sooner depending on scope.