Callstack revives the Austrian AgentConf name in Warsaw: two days, one stage, thirty published speakers, for engineers who already run AI agents in production.
A two-day conference on agentic software development, held in Warsaw and run by the Polish software house Callstack. The organiser expects 500 engineers. The published schedule is a single stage, not parallel tracks: the four labels used on the site (Vibe Coding, Agentic Engineering Fundamentals, Orchestration and Multi-Agent Systems, Adoption and Case Studies) tag each talk by theme, they do not split the room. The name is inherited: AgentConf was a JavaScript and React conference held in the Austrian Alps until 2023, and Callstack states it is opening a new chapter for it in Warsaw with a different subject.
17 and 18 September 2026, first talk at 09:15 on day one, closing at 17:20 on day two followed by an after party at 18:00. Crowne Plaza Warsaw The HUB, rondo Ignacego Daszynskiego 2, in the Wola business district. A separate paid workshop day runs on 16 September 2026 at the same venue.
Callstack, trading as Callstack.io sp. z o.o., a Polish company whose registered office is in Wroclaw, not Warsaw, per the event terms and conditions. Callstack created React Native EU in 2017, later renamed React Universe Conf, and claims more than 20,000 attendees across its whole conference history, a figure that covers all of its events and not this one.
500 engineers, an organiser target rather than an audited count, and the same figure the organiser used in its call for speakers in May 2026. The stated audience is software engineers, AI engineers and engineering leads already building or evaluating agent systems. No attendee breakdown by seniority, country or company size is published.
The site lists thirty names, the roster below, and states that more are still to come. Two further people appear only elsewhere on the site: Bartek Pucek (The Thinking Company) on the day-two panel, and Giovanni Laquidara (Amazon) leading the workshop day.
Everything a returning AgentConf visitor knew has changed. The event ran in Dornbirn, Austria until 2023 as a JavaScript and React conference with ski days in Lech, organised by Alpine Conferences. The 2026 edition is in Warsaw, organised by Callstack, and the subject is AI agents. The old domain agentconf.io no longer resolves; the site is now agent.sh. Anyone who attended in Austria should treat this as a new event that kept a name.
Twenty-five minute slots on one stage, tagged by the four angles the organiser says shape agentic development. Vibe Coding: prompting as an engineering skill, knowing when to steer an agent and when to let it run, reviewing code an agent wrote. Agentic Engineering Fundamentals: context, memory, tools and feedback loops, then cost, latency and failure modes. Orchestration and Multi-Agent Systems: agent orchestration proper, splitting work across specialised agents, coordinating state and responsibility, and where a human checkpoint belongs. Adoption and Case Studies: accounts from teams that moved AI-driven workflows out of experiments and into production, what scaled, what broke, and how the gain was measured beyond a feeling of speed. Day one opens at 09:15 with Nader Dabit and runs through talks from Allegro, Expo, Open Mercato, Amazon, Sierra, AT&T, CSOB and IBM, closing with networking at 17:20. Day two opens at 09:15 with OpenAI, then Meta, Stately, EpicWeb.dev, Grafana Labs, eBay, Sizzy, Natech, Postman and Vercel, and ends with a panel on the future of software development at 16:45 and an after party at 18:00. Recurring subjects: prompting as an engineering discipline, agent memory and failure modes, observability for agents, multi-agent coordination, and production case studies with measured results. Two day-two slots were still marked TBA on 9 September 2026.
Conference talks of twenty-five minutes on a single stage, one panel discussion, and one full-day hands-on workshop the day before. No exhibition floor, no roundtables and no organised matchmaking are described. There is a hosted after party on the evening of day two, and a speakers dinner reserved for the roster.
One pre-conference workshop, "Build Your Own Software (re)Factory", on 16 September 2026 at the same venue, led by Giovanni Laquidara of Amazon, from 10:00 to 14:30, and marked sold out on the official page on 9 September 2026. On the conference days themselves: networking at the end of day one, and an after party from 18:00 on day two, both included in the ticket. Callstack has also negotiated rates at two neighbouring hotels, Crowne Plaza and Holiday Inn, for 15 to 19 September.
One tier is on sale: Late Bird at 799.50 EUR including 23 percent Polish VAT, which is 650 EUR before tax. It opened on 2 September 2026 and covers both conference days, all meals and refreshments, and the after party. Earlier tiers are no longer offered. Group orders of three or more take 15 percent off with the code Teams15, announced by the organiser on its own account. A 10 percent code, TWIR, was circulated through a paid newsletter placement. Payment is in euros through Tito and Stripe; a tax invoice follows by email within fourteen days rather than at checkout. The workshop day is a separate purchase and is sold out.
The call for speakers closed on 20 June 2026 and is not reopening for this edition. It ran on Sessionize from 7 May, asked for original twenty-minute talks from intermediate and advanced practitioners, and promised notification by 30 June. Accepted speakers received a full ticket, three nights at the speaker hotel, an invitation to the speakers dinner, and travel support of up to 1,200 EUR for intercontinental flights or 600 EUR for European ones. Anyone aiming at the next edition should expect a spring call on the same platform.
Partnership goes through gutek@callstack.com, with a partner deck available on request and a booking link to Mateusz Kornacki of Callstack for a call. Six levels are visible on the site: Platinum, Gold, Silver, Partnership, Community Partner and Media Partner. Prices are not published, and no exhibition stands are described: what sponsors get in practice is not stated anywhere public.
Fourteen organisations are shown, by level:
Amazon appears twice over: as the only Platinum sponsor and as the employer of three speakers and of the workshop lead.
No attendee breakdown is published, so the only evidence is the speaker roster and the sponsor list. Both point the same way, and in two clusters. First, vendors of agent tooling and infrastructure: OpenAI, Cursor, Cognition, Sierra, Stately, Vercel, Expo, Postman, Grafana Labs, Apify, Rork. Second, in-house platform and engineering teams at large consumer and financial companies: Amazon, Meta, IBM, AT&T, eBay, Allegro, CSOB, Natech. Polish employers are well represented, which is consistent with a Warsaw venue and a Polish organiser. Consultancies and agencies are thin on the ground apart from the host itself.
Not publicly disclosed. The site publishes no press page, no media kit and no accreditation form. The only general address given anywhere on the site or in the terms is conference@callstack.com, which is the ticketing and complaints address rather than a press desk; a journalist has nothing better to write to.
One placement is confirmed and it was paid for: the React community newsletter This Week In React carried Agent Conf in issue 285, flagged as a sponsor item, with the dates, six speaker names and the discount code TWIR. Two Polish media are listed as official media partners, Ucz Mnie (media partner) and justjoin.it (media partner), so anything they publish is placed rather than independent. Beyond that, coverage is aggregator listings, Crossweb and 10times among them, which reproduce the organiser's own copy. No independent editorial review was found for the Warsaw edition.
Low, and transparently so. Everything traceable falls in the first two of the four categories used here: placed coverage bought by the organiser (This Week In React issue 285, marked as a sponsor item) and coverage from declared media partners, Ucz Mnie (media partner) and justjoin.it (media partner). Nothing independent has appeared, which is expected for a first edition under a new organiser. The consequence for a reader: the attendance figure, the speaker count and the description of the audience all come from one source, the organiser, and none has been checked by a third party.
Anyone looking for a trade show. There is no exhibition floor, no matchmaking programme and no buyer-seller structure, so a vendor hoping to work a stand will find nothing to work. Anyone wanting an introduction to AI coding assistants should also think twice: the call for speakers asked for intermediate and advanced material, and the schedule is weighted toward production problems, observability, quantisation and multi-agent coordination. And anyone who came for the Austrian AgentConf, its JavaScript programme or its ski days, is looking at a different event that kept the name.
In the mid-September slot of the developer AI circuit, and it is the Warsaw entry in that circuit. Its closest neighbours by subject are Agentic Engineering Days Zurich and the AI Coding Summit London edition, the latter listed here as one of Agent Conf's own community partners. Counting the workshop day, it asks for three days from 16 to 18 September. Callstack's other conference, React Universe Conf, is a separate event on a separate subject and is not part of this ticket.
Not in 2026. Warsaw is the only edition, and no second city or online edition is announced. Historically the name travelled: AgentConf was an annual winter fixture in Dornbirn, Austria, six editions in all, the last in February 2023, with ski days in nearby Lech, under Alpine Conferences. Callstack presents the Warsaw event as the continuation of that series. Whether the name changed hands formally, and on what terms, is not documented publicly. No 2027 date is announced, so the annual rhythm is inherited from the Austrian series rather than confirmed for Warsaw.
English. Every talk title, the site, the terms and the call for speakers are in English, and the roster is drawn from ten or more countries. The organiser does not state this in so many words, and no interpretation into Polish is offered.
The call for speakers described the Warsaw edition as onsite plus live streamed (unverifiable information). Nothing on the official site, the ticket page or the terms mentions a stream, an online pass or recordings: the single ticket on sale grants physical access only, and no replay policy is published. Treat remote attendance as unconfirmed until the organiser says otherwise.
Tickets are non-refundable. The published terms allow a refund in only two cases: the conference is cancelled, or its date or city changes less than sixty days before the event. Illness, visa refusal, travel trouble and a change of mind are named and excluded, and the terms apply that exclusion to consumers as far as Polish law allows. What is permitted instead is reassignment: a ticket can be transferred to a substitute at no charge if Callstack is told before the event and given the new attendee's details, though the payer cannot be changed and resale for profit voids the ticket. Refund requests must be made within thirty days of the scheduled date. Polish law governs, and Polish courts have jurisdiction.
Not publicly disclosed. No accessibility statement, step-free access note, captioning or dietary and assistance form is published on the site or in the terms. The code of conduct forbids discrimination on the basis of disability, which is a behaviour rule and says nothing about the building. The venue is a modern hotel conference centre with underground metro access, so step-free entry is likely, but the organiser has not confirmed it.
Crowne Plaza Warsaw The HUB, rondo Ignacego Daszynskiego 2, 00-843 Warsaw, in the Wola business district. The organiser publishes no travel page at all, only a Google Maps link, so the practical answer comes from the hotel and from Warsaw's transport operator. The building sits directly above Rondo Daszynskiego station on metro line M2, with access from the station concourse, which is how almost every route ends. From Warsaw Chopin Airport, about fifteen minutes by taxi or ride-hailing, or by public transport from the rail station under the arrivals level: SKM line S3 to Warszawa Centralna or line S2 to Warszawa Srodmiescie, or bus 175, roughly thirty minutes to the Centrum stop, then M2 westbound to Rondo Daszynskiego. From Warszawa Centralna, the main railway station, it is a walk of about one kilometre north west, or one stop on M2 from Rondo ONZ, the next station east of the venue. The night bus from the airport is the N32. A 75 minute Warsaw transport ticket covers any of these legs; the conference includes no shuttle.
The old AgentConf sold a place as much as a programme: Dornbirn, then two days on the slopes at Lech. Warsaw sells the opposite, a hotel above a metro station in an office district, fifteen minutes from the airport, with a workshop bolted on the day before. That is a deliberate exchange of atmosphere for density, and it fits an audience the organiser describes as engineers already running agents in production rather than people looking for a week away. The risk is equally plain: without the ski days, the event has to be worth 799.50 EUR on the strength of twenty-five-minute talks alone.
Five hundred is an organiser target, unaudited, and it is the number everyone will quote. The roster is the harder fact and it is verifiable line by line: OpenAI, Cursor, Cognition and Sierra on the tooling side, and Amazon, Meta, IBM, AT&T, eBay, Allegro and a Czech retail bank on the side of teams that have to make agents survive a production incident. A first edition that books both halves has answered the question that matters more than the door count, which is whether the room contains anyone who has shipped this.
Every figure on this page above the ticket price comes from Callstack: the five hundred engineers, the thirty-plus speakers, the twenty thousand attendees across its history. None has been counted by anyone else, and the only press coverage traced for this edition was bought or placed with declared media partners. That is normal for a first edition and it is not an accusation, but it does mean the honest reading is a target and not a measurement. The one number a buyer can verify is 799.50 EUR, because it is charged at checkout.
Official site: agent.sh, which redirects from www.agent.sh and carries the roster, agenda, workshop page, sponsors and legal pages. Tickets are sold through Tito at ti.to/agent-conf/agent-conf-2026 and nowhere else; an Eventbrite listing exists but sends buyers back to agent.sh. The organiser also maintains a page at callstack.com/events/agent-conf, and the closed call for speakers stays readable at sessionize.com/agent-conf-2026. General and ticketing enquiries go to conference@callstack.com, partnership enquiries to gutek@callstack.com. The historic domain agentconf.io no longer resolves and should not be cited.