The four sub-reports converge on a single, almost embarrassing fact for a Ghent-based senior dev: the densest concentration of 2026 flagships happens within an hour of home. Antwerp alone hosts Techorama Belgium (May 11-13) [1], DDD Europe (Jun 8-12) [2], and Devoxx Belgium (Oct 5-9) [3] — covering .NET, architecture, and the Java/AI generalist circuit respectively. Brussels adds FOSDEM (Jan 31-Feb 1) for free [4]. The “short flight or train” filter barely needs to be applied; staying local already buys three of the strongest events on the European calendar.
Two months bear the load: June and October. June stacks NDC Copenhagen Jun 1-4 [5], DevSum Stockholm Jun 1-3 [6], Craft Budapest Jun 4-5 [7], DDD Europe Jun 8-12 [2], AI Summit London Jun 10-11 [8], and ICSA Amsterdam Jun 22-26 [9] — six flagships, four overlapping pairs. October overlaps Devoxx Belgium with JAX London (both Oct 5-9) [3][10], then runs ai-PULSE Paris Oct 13 [11], .NET DeveloperDays Warsaw Oct 19-23 [12], Code BEAM Haarlem Oct 21-22 [13], and Techorama Netherlands Oct 26-28 [14] on consecutive weeks. Pick at most one per cluster.
The AI/architecture/SE separation is collapsing on the program side. Devoxx Belgium runs an explicit Architecture track on multi-agent systems, A2A and MCP [3]; KubeCon EU 2026’s keynotes were AI-infra dominated [15]; QCon London’s 20th-anniversary edition leaned into agentic AI and platform ROI [16]. The implication: a generalist event with a strong AI track (Devoxx, GOTO Copenhagen [17], NDC Oslo [18]) can substitute for a dedicated AI conference unless you need depth on a specific subspecialty — which is where ML Prague (May 4-6) [19] or Applied AI Berlin (May 28) [20] earn their slot.
The original brief asked for CFP deadlines surfaced; the children only partially delivered. The Devoxx Belgium CFP runs Jun 1 - Jul 17, 2026 [3] — the one window cited explicitly. iSAQB Software Architecture Forum Munich’s very-early-bird closed Apr 2 [21]; NDC Oslo all-access early bird ends May 22 [22]; GOTO Copenhagen’s early bird closed May 1 [17]. Other CFPs aren’t surfaced in the source pages — for autumn-2026 and 2027 events with windows still open, dev.events’ architecture and .NET feeds are the recommended discovery channels [23][24].
Already past for 2026 (mark for 2027 cycle): FOSDEM Brussels [4], KubeCon EU Amsterdam Mar 23-26 [15], QCon London Mar 16-19 [25], OOP Munich (next: Feb 2-5, 2027) [26], NDC London (next: Jan 25-29, 2027) [27], WAICF Cannes, AMLD Lausanne, PyTorch Conf Europe Paris, PyCon DE Darmstadt, Voxxed Days Bucharest. The most striking absence on the autumn calendar is GOTO Aarhus / Amsterdam — both dark in 2026, leaving Copenhagen as the year’s only European GOTO stop [28].
If the budget allows one paid flagship plus one local: Techorama Belgium + GOTO Copenhagen is the highest-signal pairing — home-turf .NET depth in May, agnostic engineering practice in late September, with FOSDEM and Devoxx Belgium as free / low-cost bookends. The open question worth answering before booking: does the Techorama Netherlands edition in late October [14] ever justify a second .NET conference in the same year, or is Update Conference Prague (Nov 12-13) [29] the better second .NET stop?
CFP picture for speakers
A May-1 follow-up sweep across the same calendar surfaced a sharper CFP picture than the children captured. Open right now and worth submitting: NDC TechTown Kongsberg (closes 3 May ⚠), .NET DeveloperDays Warsaw (10 May), Techorama NL (29 May), DDC Cologne (15 Jun), iSAQB SAG Berlin opens 5 May, and Devoxx Belgium opens 1 Jun. Academic windows still ahead: NeurIPS (Paris node, 4/6 May), ECSA Bolzano (multiple deadlines through 26 Jun), BMVC Lancaster (22/29 May), EMNLP Budapest (25 May ARR), CIKM Rome (16/23 May full, 30 May / 6 Jun short). Recently closed (note for the 2027 cycle): NDC Oslo (19 Apr), JavaZone (13 Apr), JAX London (13 Apr), Øredev (31 Mar), Voxxed Days Luxembourg (29 Mar), Craft Budapest (31 Jan), Devoxx UK (9 Jan), PyData London (16 Feb), DevSum Stockholm (8 Dec ‘25), NDC London 2027 (7 Sep ‘25). Curated, no public CFP: GOTO Copenhagen, QCon London, Update Conference Prague (~65 invited), ai-PULSE Paris, World Summit AI. One major correction surfaced: GSAS Barcelona has rebranded to CONVEX Summit, now in Madrid, 17-18 June 2026 — earlier in the year and a different city than initially indexed. See the per-topic CFP tables in the child reports for details, and UPCOMING_CFP.md next to this file for the consolidated cross-Europe view.