MaKo 2026: How EDIFACT, AS4 and APIs Rewire Market Communication
MaKo 2026 is the regulatory reform of German market communication (Marktkommunikation), the data exchange that runs supplier switching, metering and balancing. It is an architecture shift, not a process big bang. A binding format release took effect on 1 April 2026 under Bundesnetzagentur (BNetzA, the Federal Network Agency) Mitteilung No. 54, AS4 transport has been mandatory in the electricity market since 1 April 2024, and the first binding API process has applied since 6 June 2025. The next release follows on 1 October 2026 under Mitteilung No. 55. This article explains what MaKo 2026 really is, how EDIFACT, AS4 and APIs fit together, who is affected, the staggered deadlines, and what utilities should do now.
MaKo 2026 reshapes the data architecture behind German energy market communication while leaving the business processes broadly intact. A binding format release took effect on 1 April 2026 under BNetzA Mitteilung No. 54, consolidating the EDIFACT formats with decision trees (EBD) 4.2, check identifiers 3.3, general specifications 6.1c and OBIS codes 2.5c under the motto consolidation rather than upheaval. In parallel, the transport layer is changing: AS4 (Applicability Statement 4), an ebMS3 and web service standard, has been mandatory in the electricity market since 1 April 2024 and replaces the earlier email and AS2 transfer, while JSON web service APIs become a second channel, with the first binding API process for determining the MaLo-ID in force since 6 June 2025. The next release follows on 1 October 2026 under Mitteilung No. 55, with new message versions, EBD 4.3, API electricity 2.0.0 and updated AS4 profiles. The scale is large: market participants exchange millions of EDIFACT messages a day, around 6 million supplier switches happen in Germany each year, and a single cloud platform handles over 10 million messages a month. The reform affects all market roles, so the practical answer is a migration programme with clear enterprise architecture control rather than point fixes at each deadline.
What MaKo 2026 really is: an architecture shift, not a process big bang
MaKo 2026 is best treated as a data architecture and integration topic, not a pure business project. It is not a single event but a staggered rebuild of market communication that leaves the business processes broadly stable and instead modernises formats, transport paths and interfaces. The current format release took effect on 1 April 2026, and the BNetzA itself places it under the motto consolidation rather than upheaval.
A short clarification matters here. MaKo 2026 is the regulatory reform of market communication itself, not the SAP product Mako Cloud, which is one vendor's software for handling that communication. The release under Mitteilung No. 54 brings EBD 4.2, check identifiers 3.3, general specifications 6.1c and OBIS codes 2.5c, with clearer mandatory field definitions, harmonised reference logic and less room for interpretation in the validations. It touches the core processes GPKE, WiM, MaBiS and GeLi Gas, that is supplier switching, metering, balancing and gas supply. Where a single vendor platform fits into this picture is set out in innobu's guide to the SAP Mako Cloud .
From EDIFACT to API: two worlds in parallel
The real technological marker is the move from a purely file-based EDIFACT exchange to synchronous API web services with JSON. EDIFACT messages such as UTILMD, MSCONS or INVOIC remain in place for now, but BNetzA and the BDEW (the German energy and water industry association) state plainly that APIs are meant to replace EDIFACT step by step. The first binding API process, for determining the MaLo-ID (the market location identifier), has applied since 6 June 2025 and marks the entry into a gradual migration.
The two channels coexist rather than switch over at once. Mitteilung No. 55 takes the single API web service for determining the MaLo-ID and splits it into several functionally separate services, and it delivers API web services electricity release 2.0.0, which has moved from Swagger to GitHub. For an integration team this means EDIFACT and API are not an either or but two structures to be kept in sync.
AS4: the new transport layer under the hood
While formats and APIs concern the content, AS4 governs the transport. AS4 (Applicability Statement 4) is a standard based on ebMS3 and web services that has been mandatory in the German electricity market since 1 April 2024 and replaces the earlier transfer of EDIFACT messages by email and AS2. The channel becomes more secure, acknowledged and auditable, which is decisive for the mass operation.
AS4 covers the core processes GPKE, MPES, WiM and MaBiS, while schedule exchange and Redispatch 2.0 are governed separately. The communication security rests on the Smart Metering PKI and the cryptography standards of the BSI (the Federal Office for Information Security), with the transport secured by TLS. Mitteilung No. 55 updates the AS4 profiles to version 1.2 and the transmission rules to version 1.10, each binding from 1 October 2026. The same secure transport that carries today's EDIFACT messages will carry the growing share of API traffic, which is why the transport layer is the part to get right first. The grid-side context, from metering to control, runs alongside this, as innobu set out for the control box and Section 14a .
Who is affected and what happens in the systems
The change touches every market role at once, from the grid operator through the energy supplier and metering point operator to the balancing group responsible party. For municipal utilities with grown IT estates this means adapting energy data management (EDM) systems, converters and interfaces in step with each deadline, without interrupting the live operation. The quality of the data architecture decides the effort and the risk.
EDM and billing systems have to support new format versions, AS4 connectors and API clients at the same time. The mapping between EDIFACT, internal structures such as IDoc and JSON APIs becomes a permanent part of the integration estate rather than a one-off conversion. The roles affected, grid operators, suppliers, metering point operators, balancing group responsible parties and municipal utilities, are in practice all market participants.
This is where data architecture stops being a back-office concern. A clean separation between the message format, the transport connector and the partner endpoint lets a team absorb a new release by changing one layer rather than rewiring the whole chain. A grown estate that mixes these concerns pays for it at every BNetzA deadline.
The roadmap: staggered deadlines, not a single cut-off date
MaKo 2026 is organised as a rolling roadmap in which the BNetzA sets consultation and binding dates in numbered Mitteilungen. The release of 1 April 2026 under Mitteilung No. 54 is followed by the next bundle of formats and services under Mitteilung No. 55, binding from 1 October 2026. Whoever sets the programme up as a standing task rather than a one-off project stays able to deliver.
The layering matters for planning. The mail-based EDIFACT transfer has been replaced step by step since late 2023, AS4 carried that shift, and APIs arrived in early 2025 as a fast B2B channel on top. There is no single switchover date to plan against, only a sequence of binding releases that a programme has to meet one after another.
What utilities and municipal utilities should do now
The economically sensible answer to MaKo 2026 is a migration programme with clear enterprise architecture control, not point fixes at each deadline. Whoever bundles the EDIFACT, AS4 and API paths into one integrated architecture and encapsulates converters and interfaces cleanly reduces the adaptation effort at every new release. A regulatory duty then becomes a stable foundation for further digital work.
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Define a target architecture with coexisting channels
Set out a target architecture that encapsulates EDIFACT, AS4 transport and API web services as coexisting channels, so each can change without forcing changes in the others.
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Maintain converters and mappings centrally
Keep converters and mappings in one place, so that new format versions and API releases land in the mass operation without a break and without scattered local patches.
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Couple the programme to the BNetzA deadlines
Tie the programme to the BNetzA binding dates and run it as a standing task, with each numbered Mitteilung treated as a planned release rather than a surprise.
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Connect to the wider regulatory picture
Think through the links to Redispatch, the smart meter rollout and Section 14a EnWG, because the same EDM and integration estate carries those duties as well.
The releases are binding now, and the next deadline is close. Whoever defines a target architecture, maintains converters centrally and couples the programme to the BNetzA dates turns a regulatory duty into a stable foundation. The wider grid context, from the metering base outward, fits in the same plan, as innobu set out for the smart meter rollout .
Further reading
Frequently asked questions
MaKo 2026 is the regulatory reform of German energy market communication (Marktkommunikation), the data exchange that runs supplier switching, metering and balancing. It is an architecture shift rather than a process big bang: the business processes stay broadly stable, while formats, transport and interfaces are modernised. A binding format release took effect on 1 April 2026 under BNetzA Mitteilung No. 54, file-based EDIFACT moves to mandatory AS4 transport and new JSON web service APIs, and the next release follows on 1 October 2026 under Mitteilung No. 55. It is not the SAP product Mako Cloud, which is one vendor's software for handling market communication.
EDIFACT is the message format, the structured content of messages such as UTILMD, MSCONS or INVOIC, exchanged asynchronously as files. AS4 (Applicability Statement 4) is the transport layer, an ebMS3 and web service standard that has been mandatory in the German electricity market since 1 April 2024 and replaces the earlier email and AS2 transfer. API web services with JSON are the new synchronous channel: they allow a near real-time dialogue with a defined start and end point. The three operate together, with the format carried over a secure transport to a partner endpoint.
AS4 transport has been mandatory in the German electricity market since 1 April 2024. It is based on the ebMS3 and web service standards, secures the channel with TLS, and relies on the Smart Metering PKI and BSI cryptography standards for communication security. AS4 covers the core processes GPKE, MPES, WiM and MaBiS, while schedule exchange and Redispatch 2.0 are governed separately. Under BNetzA Mitteilung No. 55 the AS4 profiles move to version 1.2 and the transmission rules to version 1.10, binding from 1 October 2026.
The migration affects all market roles: grid operators, energy suppliers, metering point operators, balancing group responsible parties and municipal utilities. In practice every market participant is touched. Energy data management (EDM) and billing systems must support new format versions, AS4 connectors and API clients at the same time, and mapping between EDIFACT, internal structures such as IDoc and JSON APIs becomes a permanent part of the integration estate. For utilities with grown IT estates the challenge is to adapt converters and interfaces in step with each BNetzA deadline without interrupting the live mass operation.
MaKo 2026 runs as a rolling roadmap of numbered BNetzA Mitteilungen rather than a single cut-off date. AS4 transport has been mandatory since 1 April 2024. The first binding API process, for determining the MaLo-ID, has applied since 6 June 2025. The format release under Mitteilung No. 54 became binding on 1 April 2026. The next release under Mitteilung No. 55, with new message versions, EBD 4.3, API electricity 2.0.0 and updated AS4 profiles, is binding from 1 October 2026, with the consultation having closed on 27 February 2026.