How to Choose a Tech Recruitment Agency in London

London has hundreds of recruitment agencies that will take an engineering brief. Very few will improve on what your own team could do with a job advert and a spare afternoon. The difference is not the logo or the size of the database. It is who does the work, how they assess people, and what the contract commits each side to. This is the checklist we would use if we were buying.

Start with who does the screening

The single question that separates agencies is: who speaks to the candidate before I do, and what do they ask? If the answer is a resourcer matching CV keywords, the agency is a sourcing service and should be priced like one. If the answer is someone who has done the job, who asks about the systems the candidate built and the trade-offs they made, you are buying technical screening, which is the part of recruitment that actually saves a hiring team time.

Ask for a sample of the written summary that arrives with a CV. If there is no written summary, there was no screen.

Match the model to the role

Agencies sell three engagement models and most will push whichever they prefer. Choose by the role instead.

• A single mid or senior hire where good candidates exist in reasonable numbers: contingent recruitment, paid only on a start.
• A leadership or genuinely scarce role where a wrong hire costs a year: retained search, with a committed process and full market mapping.
• Several roles at once, typically after a funding round: embedded recruitment, a recruiter inside your team for a fixed period.

Our guide to recruitment models sets out the trade-offs in detail, and the contingent versus retained comparison covers the two most people choose between.

Read the terms before the role is urgent

Most companies sign agency terms on the day a role becomes urgent, which is the worst moment to read a contract. Four clauses decide what you will actually pay.

1. Fee basis and timing. Usually a percentage of first-year salary, invoiced on start. The percentage varies with scarcity and volume, so compare the whole agreement, not the headline rate.
2. Rebate or replacement. The rebate period says what happens if the hire leaves early: a sliding-scale refund, a free replacement search, or nothing. Check which, and whether it applies if you dismiss the person.
3. Introduction period. If you hire someone the agency introduced within a set period, even through another route, you owe the fee. Know how long that period is and keep a record of who introduced whom.
4. Transfer fees. For contractors, the rules on temp-to-perm fees are set by the Conduct of Employment Agencies and Employment Businesses Regulations 2003, which also require an agency to agree its terms with you before it supplies anyone. An agency that starts sending CVs before you have seen terms is already cutting corners.

Check the proof is from clients

Read the agency’s reviews and notice who wrote them. Candidate reviews tell you how the agency treats people it places, which matters. They tell you nothing about whether it fills roles for employers. Look for named clients, with roles and companies stated, and ask to speak to one. Our own client references are published with permission for exactly this reason.

Ask the questions a weak agency cannot answer

• Which three roles like mine have you filled in the last six months, and how long did each take from brief to start?
• Who will run my search day to day, and will I ever be handed to someone else?
• How many roles is that person running right now?
• What will you tell a candidate about us that we have not told you?
• Which roles have you turned down this year, and why?

The last one matters most. An agency that has never declined a brief will take yours whether or not it can fill it.

Brief one agency properly

Once you have chosen, give the agency what it needs to do the job well: the real scope of the role, the salary band, the working model, the interview stages and the decision makers’ availability. Run the advert through our free job description checker first, and if the role has been open a while, the cost of vacancy calculator will tell you what each further week is costing. A clear brief and a fast process do more for the outcome than any choice of supplier.

Where we fit

OpenSource is a founder-led tech recruitment agency in London. The founders take the brief, run the search and screen every candidate themselves; one of us was a software developer. We run engineering, product and technology leadership searches for startups and scale-ups, and we turn down the ones we cannot fill well. If that is the kind of agency you are looking for, tell us the role.

The regulatory points above summarise the UK government’s published guidance on the Conduct Regulations 2003; they are not legal advice. Check your own terms with a solicitor where the sums are material.