The Exact HR Tech Stack a 100-Person Startup Needs (and What to Skip)

A 100-person startup needs three things first: an HRIS, payroll that talks to it, and an applicant tracking system if you hire all year. Vendor guides disagree on the rest, and the legal thresholds at 50 and 100 employees set the real floor. Skip standalone performance, learning and analytics tools until review cycles or reporting get hard to run by hand.

What does a 100-person startup actually need on day one?

An HRIS is the core. BambooHR's stack guide says that at 100 employees you need "a solid HRIS that's able to handle employee data, organizational structure," plus basic benefits administration and workflows. Its list for this size includes an employee directory with custom fields, org charts, time-off management, approvals, reporting dashboards and manager self-service.

A Workable webinar summary (last modified 28 May 2024) goes further. It says core HR tools like an ATS, HCM, background check and payroll system "will meet most companies' basic needs as they scale to 100-200 employees."

My recommendation is the shorter, firmer version:

1. HRIS as the system of record.
2. Payroll connected to the HRIS, so a new hire or a raise is entered once.
3. Benefits through a broker or the HRIS, depending on how many plans you run.
4. Background checks through a provider your ATS or HRIS integrates with.
5. ATS, if you hire continuously (see below).

Everything else is optional at this size.

When should payroll and the HRIS come from the same vendor?

Usually at the start. BambooHR's guide says payroll and core benefits administration are better platform-native, because the data they need (pay rate, tax location, dependents) already lives in the HRIS. Double entry between two systems is where payroll errors start.

The trade-off is lock-in. Moving payroll later means a mid-year or year-end cutover, so pick a vendor you can live with for a few years. For a cost comparison of payroll vendors, see Gusto vs ADP vs Paychex and Rippling vs Deel vs Gusto.

What do the main HRIS vendors publish on price?

Very little, and the pattern matters more than the numbers. As of 13 October 2026, the vendors that publish and those that do not look like this:

For a rough HRIS budget, BambooHR's published rates multiplied by 100 employees give about $1,025 a month for Core, $1,750 for Pro and $2,500 for Elite before volume discounts. Payroll and benefits administration are add-ons without a listed price. Rippling's pricing page offers no number to multiply, so you need a quote to compare.

For a head-to-head on mid-size HRIS options, read BambooHR vs HiBob vs Rippling.

Does a 100-person startup need an ATS?

If you hire all year, yes. If you hire a handful of people a year, probably not. The two vendor guides disagree sharply here. Workable's webinar summary treats an ATS as standard by 100 employees. BambooHR's guide puts ATS in its 500 to 750 plus employee stage.

Both are selling something, so test the claim against your own numbers. A startup growing from 100 to 150 people in a year is running dozens of requisitions, interviews and offers. That is an ATS workload. A startup holding at 100 with ten backfills a year is not.

Pricing is one reason to decide early. Ashby's pricing page shows $400 per month for its Foundations plan, which it lists for companies of up to 100 employees, and offers a 10% discount for annual commitments. The page does not say which company-size band the $400 applies to. It also lists extras: SSO at $100 per month, and Advanced Scheduling and AI Notetaker as paid add-ons. Above 100 employees, Ashby's Plus plan has no published price.

A cheaper route is the applicant tracking built into an HRIS. BambooHR's Core plan includes applicant tracking with 5 job openings, Pro 25, and Elite 50, according to the company's pricing page. That fits a low-volume hirer. For free and low-cost options, see the free HRMS tools nobody tells small businesses about.

Which legal thresholds change what you must buy?

Three federal lines sit at or below 100 employees, and your stack has to support all of them.

On the ACA, the IRS says an employer with at least 50 full-time employees, including full-time equivalents, on average during the prior year is an applicable large employer. Part-time hours are combined (up to 120 per person) and divided by 120 to get full-time equivalents. Related companies under common ownership are generally combined.

The IRS also states that such employers must offer affordable, minimum-value coverage to full-time employees and dependents or potentially pay. The page lists indexed penalty amounts only through 2024: $2,970 per full-time employee (first 30 excluded) when coverage is not offered to at least 95 percent, and $4,460 per full-time employee who receives a premium tax credit otherwise.

The Department of Labor describes FMLA coverage for private employers with 50 or more employees in 20 or more workweeks (page last updated 26 January 2026). The EEOC says EEO-1 Component 1 is mandatory for private sector employers with 100 or more employees. Its page says the 2024 collection is closed and 2025 updates will be posted there, so check it for the current window.

The practical test for any HRIS demo: ask the vendor to show you hours-based full-time tracking, FMLA leave tracking and an EEO-1 export.

What should you skip until you are bigger?

Skip anything that solves a problem you do not yet have. BambooHR's guide warns that adding tools too early "may result in low adoption, wasted spend," and also warns against choosing tools before you have processes in place. Workable's summary makes a similar point: "Don't buy for what you might need in five years at the expense of solving today's problems."

My skip list at 100 people:

• Standalone performance management. BambooHR places these platforms at 250 to 500 employees. Before that, run goals and a twice-yearly check-in in a shared document or your HRIS.
• A learning management system. BambooHR mentions learning and development only in its 750 plus stage. Use short recorded onboarding and manager-led training first.
• Analytics and BI add-ons. BambooHR lists basic analytics at 250 to 500 and advanced analytics later. Your HRIS dashboards cover headcount, turnover and time to hire.
• Enterprise HCM suites. Workday, SAP and Oracle are built for far larger organizations. See Workday vs SuccessFactors vs Oracle HCM for what they target.
• Premium HRIS tiers you will not use. Check whether the plan you want adds features you will actually switch on.

If you employ contractors or staff abroad, that is a separate decision. See Deel vs Remote vs Oyster and the contractor payment tools guide.

What's still unclear?

Timing is genuinely disputed. Workable puts ATS and payroll in the stack by 100 employees. BambooHR puts payroll at 100 to 250 and ATS at 500 or more. Neither shows data behind its thresholds, and each vendor sells the tool it recommends earlier. Treat the headcounts as rough guides.

Prices are partial. Rippling publishes no dollar amounts. BambooHR leaves payroll and benefits administration at quote-only. Ashby shows $400 per month without stating which size band that covers. A true total stack cost for 100 employees cannot be built from public pricing alone, so get quotes before you set a budget.

The sources are vendors. The two stack guides come from companies that sell HR software. Government sources set the legal floor, but the "what to buy" side of this article rests on vendor opinion plus my own judgment about hiring volume.

Compliance dates move. The EEO-1 filing window is announced by the EEOC, and the IRS penalty amounts on its page stop at 2024. Confirm both before you plan around them.