The textbook split is simple: an SDR works leads that came to you (inbound), a BDR goes after accounts that never heard of you (outbound). In France and most of Europe the two titles are used almost interchangeably, so the real question is not the label but the lead source, the rhythm of the day and the KPIs you attach to the seat. Hire for the source of pipeline you are missing.

SDR vs BDR: the textbook definition

The distinction comes from US SaaS org charts of the 2010s.

• SDR (Sales Development Representative). Takes marketing-generated leads (demo requests, content downloads, trial sign-ups), calls them fast, qualifies them, books a meeting for an AE. Speed is the job.
• BDR (Business Development Representative). Builds target lists, researches accounts, cold calls and sequences people with no prior contact, books discovery meetings. Persistence is the job.

Neither role is senior to the other. They sit at the same level, feed the same AEs and usually share the same manager. Some companies flip the definitions. Ask what the seat does, not what it is called.

How the titles are really used in Europe

In France, "SDR" has become the generic word for any pipeline-generation role, inbound or outbound. Most French SaaS job posts titled SDR describe cold outbound work. "BDR" appears mostly in companies with a US parent or a US playbook.

Be careful with "Business Developer" in French job ads. It usually means a full-cycle salesperson who prospects and closes, closer to an AE than to a BDR. A candidate who reads "BDR" as "biz dev" will expect to close deals. Write the funnel stage in the first line of the offer.

In the UK and the Netherlands, the US split is more common. In DACH, "SDR" dominates and inbound is often handled by marketing or an "Inside Sales" team. None of this changes the work. It changes who applies.

Same dialer, two very different sessions

The clearest way to see the difference is to watch the two roles for one hour on the phone.

The inbound SDR runs a speed-to-lead session. A demo request arrives, the SDR calls within five minutes, one dial at a time, with the form answers on screen. Connect rates on fresh inbound are high, and the opener is easy: "You asked for a demo on Tuesday, I am calling to find the right slot." The skill is speed and qualification, not persuasion.

The outbound BDR runs a parallel-dialing session at the hours people pick up. The 1,000,000-call benchmark we built with Quentin Despas (Katana) shows an average 11.3% connect rate in French B2B, 15.8% at 4pm and 14% at 10am. The BDR needs around 180 dials to get 20 conversations. The opener is the whole game: 65% of reps open by explaining what they sell, and that lands a 2-3% meeting rate. A trigger-based opener lands 7-10%.

Put an inbound SDR on cold outbound without changing the tool, the hours and the opener, and the meeting count collapses. The reverse is less dramatic but costs money: a BDR profile is paid for persistence you do not need on inbound.

KPIs for each role

Inbound SDR. Speed to first call (minutes), lead-to-meeting rate, meeting show rate, AE acceptance rate. Volume is given by marketing; the SDR owns conversion and speed.

Outbound BDR. Conversations per day (our north-star is 20), meetings held per month, AE acceptance rate, cold pipeline sourced per quarter. Dials and connect rate are health indicators, useful when a result drops.

One shared rule: both are measured on meetings held and accepted, never on activity alone. A BDR paid on dials will dial; an SDR paid on leads touched will touch leads.

Which one should you hire first?

Run three checks.

1. Where is pipeline leaking today? If inbound leads wait more than an hour for a call, or AEs spend their mornings qualifying form fills, hire an inbound SDR. If inbound volume cannot fill AE calendars, hire an outbound BDR.
2. Do your AEs still prospect? Under five salespeople, in our experience, a full-cycle AE with a parallel dialer often beats a first BDR hire. The AE knows the product and the objections. Give them two calling blocks a day before you open a seat.
3. Are you opening a new market? A new country or segment has no inbound. That is BDR work by definition, and a good place to test an outsourced team for three months before hiring in-house.

Teams below ten people usually run one "full-stack" SDR who does both. It works until inbound volume and outbound targets both grow; then the inbound work eats the calling blocks and outbound dies quietly. Split the roles at that point.

Pay and career path

In the offers we see from our French customers in 2026, BDRs earn slightly more than inbound SDRs, roughly €2,000-5,000 more on OTE, because cold outbound carries more rejection and more skill. Both roles move to AE in 12-18 months when quota is hit, and both feed SDR lead, RevOps and customer success roles. Publish the criteria; it is the first thing strong candidates ask.

How Sonik approaches SDR and BDR work

We built the dialer for both sessions. Outbound reps run parallel sessions at the slots the benchmark recommends and get about 5x more conversations per hour. Inbound reps run single-line speed-to-lead sessions with the lead's context on screen.

The signals layer blurs the line on purpose. A website visitor, a job change on a target account or a dormant lead is neither pure inbound nor pure cold. On our own team, 50% of pipeline comes from signals that were already in the CRM, and the same rep handles them in the same session.

Conclusion

SDR and BDR are two jobs with the same output and different inputs: warm leads and speed on one side, cold accounts and persistence on the other. In Europe the titles overlap, so define the seat by its lead source and its KPIs. This week, count how many of last month's meetings came from inbound versus cold outbound. The smaller number tells you which role to hire.