Every supplier describes its screening the same way: rigorous, multi-stage, few applicants accepted. The claim is unfalsifiable by design, which is why it is on every website — and the wrong thing to ask about.
An acceptance rate describes whoever happened to apply, over a denominator the vendor controls and you cannot see. The funnel for your brief is a different object — stages, counts and names — and a supplier who screens produces it in one written reply. The five questions below are ordered by how fast a weak answer surfaces.
1. How many did you consider, and how many did you reject?
You want the shape of the funnel for your role, not the size of the bench. "We looked at eleven, screened six, rejected four, and these are the two in front of you" is an answer. "A large pool of pre-vetted senior engineers" describes inventory.
The tell is a supplier who presents exactly as many profiles as they considered: that is allocation, not screening. An idle engineer costs money every week they sit, and that pressure lands on their margin or your shortlist.
2. Where did the rejections happen, and why?
Rejections carry more information than acceptances. Ask for them by stage: rejected on English, on system design, on availability, on never having been on call. A supplier with a rubric answers in a sentence per candidate. One without says "not quite the right fit" four times — nobody wrote the bar down first.
Then ask the uncomfortable version: what did you reject that I might have liked? A real answer has at least one — strong but wrong on hours, wrong on domain, asking above the band. If every rejection was self-evidently correct, you are reading a story, not a record.
3. Who ran the technical screen, and what do they build?
Ask for a name, a role, and what that person shipped recently. An engineer who still writes code can tell you why a candidate's answer to a design question was weak. A recruiter can tell you they used the right words, the one skill they have been practising.
It also reveals whether the screen exists at all. Sourcing is a service a supplier can buy and resell, and the sign it did is that nobody there can name who discussed code with the candidate.
4. What happens when nobody passes?
It is the only one of the five whose answer cannot be prepared in advance. The honest answers are narrow: we cannot fill it, or the timeline is longer than the one we quoted.
So ask it directly: when did you last tell a client no, and for what role? A supplier with candidates for every brief inside the same week is selecting on their own availability, not on your requirements, and one who has never said no has never had a bar — by that test we have nothing to show either: the studio is new, and no client of ours has yet been told no. What is checkable is the timeline, not a history of refusals: first candidates inside five business days when the stack is common, ten to fifteen when it is not, with Go, iOS and Vue in the latter, and which group yours falls in said before you send the brief.
5. Show me a rejection note
Anonymised, for a role like yours; two paragraphs is plenty. You are not reading the candidate but the supplier's reasoning, written when nothing was commercially at stake. That shows in a rejection as it never does in a pitch.
Why a candidate video beats a resume
A resume is a document optimised by a third party, often the vendor, for precisely the screen you are running. A short video of the candidate answering your brief in their own words is a different instrument:
- It is responsive, not generic. A resume matches keywords. A video either engages with your problem and your hours, or visibly does not.
- It surfaces the question. Watch what they ask about the brief. A strong senior always has something to ask, and its specificity is the cheapest seniority signal you get.
- It puts the English check in the right medium. Enough to judge whether a live interview is worth scheduling, without making spoken fluency the first filter on written work.
- It tells you about the supplier. If three videos answer in the same order with the same phrases, you are watching coaching, not candidates — which no reference call would have shown you.
A video is not a technical screen, though, and nerves cost people marks in any language. Weight it for engagement, not polish; reading the answers right is a separate problem.
The question screening does not answer
Screening absorbs all the diligence, and then the engagement dies of something else: the engineer leaves in month nine and the supplier files it under attrition. One question prices that risk up front.
- Is the engineer dedicated to one client, in writing? A split engineer is a retention problem dressed as an efficiency: hours quietly sold twice give you two managers and no owner. Ask for the clause, not the assurance.
Everything else that decides whether they stay is yours, not the supplier's: flattened work, a calendar creeping past their dinner, a rate nobody has revisited. What makes a senior engineer leave is the longer list, worth reading before you price screening as the whole risk.
Then discount the category honestly, HireBrazilDevs included. A young supplier has no retention history, and any figure it quotes is either someone else's or invented. What it can offer instead is paper you read before signing: one client per engineer, no substitution without your written approval, a resignation disclosed the day it is known, a replacement at no cost in the opening month, and symmetrical notice. The whole agreement is one page and published. Weigh that as a commitment, not a track record — and weigh an incumbent's twelve years as what that is, too.
When this diligence should send you elsewhere
The audit has an outcome suppliers do not advertise: sometimes you should not buy screening at all.
- You already own the funnel. With an in-house technical recruiter and a brand engineers apply to, your pipeline out-screens any vendor's for a permanent role.
- The work is a scoped six-week project. A dedicated engineer is the wrong shape; a project team with its own lead is right, and the scope matters more than the screening.
- The person has to be on your payroll. Some security reviews and customer contracts require it outright, and no screening changes that.
- Two engineers already failed in the same seat. No screen can diagnose a seat; a third shortlist only re-runs the experiment. The early signals usually point at the brief, the access or the owner.
Send it in writing
Send all five in one email, not five. Split across messages, a supplier answers the two that flatter it and the rest get lost in the thread; one numbered list makes a gap a decision rather than an oversight. Ask for the reply in writing, in that same sentence — a supplier who turns written questions into a call is choosing the medium that leaves no record, and the offer of a quick call is itself an answer. Then let the clock be the last question: one business day is comfortable for anyone who already keeps rubrics and rejection notes, and nowhere near enough for anyone inventing them.
A supplier who answers all five questions in a day has a screening process. One who answers with adjectives and offers a call has a resume forwarding service. You find out which in month three either way; the difference is five questions and one business day.