eCoCs Explained: What the UK's Electronic Certificate of Conformity Means for Vehicle Manufacturers

If you build or import vehicles in the UK, the paper Certificate of Conformity you've handed over at the point of sale is on its way out. From 29 November 2026, manufacturers of many vehicle categories will have to send that information to the Vehicle Certification Agency (VCA) as structured electronic data, an electronic Certificate of Conformity, or eCoC. This isn't a small formatting tweak. It's a shift from a printed document to machine-readable XML files that have to pass validation before they're accepted, and it changes how your systems need to produce and submit that data.

Below is a plain-English walk through what the VCA has published: what an eCoC is, who's in scope, the deadlines, the file format, and the two ways you can actually get the data to the VCA. We've also added our own practical take on the build side, because the moment a regulator says "submit structured data via an API", it stops being a paperwork job and becomes a software one.

Key takeaways

• A Certificate of Conformity confirms an individual vehicle was built in line with an approved type. The UK is moving this from paper to an electronic Certificate of Conformity (eCoC) in structured digital format.
• Vehicles of categories M, N and O approved under GB or UKNI type approval schemes must submit eCoCs for newly manufactured vehicles from 29 November 2026.
• The VCA's submission portal and API launched on 17 June 2026. There's no obligation to submit eCoC data for vehicles manufactured before 29 November 2026.
• eCoC files must be XML, based on the Initial Vehicle Information (IVI) 2.0 file from the EU eCoC system, with UK-specific additions.
• You can submit either by manual upload through the VCA eCoC Portal, or by system-to-system integration using an API. Both need a VCA account.

What an eCoC actually is

A Certificate of Conformity (CoC) is issued by a vehicle manufacturer to confirm that an individual vehicle has been produced in conformity with an approved type. In plain terms, it's the document that says "this specific vehicle matches the version we got approved." Historically it's been a paper document handed over with the vehicle.

The UK is now moving that from a paper-based document to an electronic Certificate of Conformity (eCoC), so the same information can be provided and used in a consistent digital format. The point is consistency: instead of a printed sheet that varies in presentation, you get structured data that any system can read the same way.

The legal driver is Assimilated Regulation (EU) 2018/858. It requires that, following a transition period, manufacturers make the CoC for newly manufactured vehicles available to the VCA as structured data in electronic format. To support that, the VCA is building a digital service for the submission and use of eCoC data for the UK market. The guidance they've published explains the approach and will be updated as the service rolls out.

Who's in scope, and who isn't

This is the part to get right first, because the answer decides whether you need to do anything at all.

In scope from 29 November 2026: Vehicles of categories M, N and O approved under either the GB or UKNI type approval schemes must submit eCoCs for newly manufactured vehicles from that date. Vehicles approved under the GB medium series, or UKNI EU small series schemes are also subject to eCoC requirements.

Exempt (can keep using paper permanently): Vehicles approved under the national small series (NSSTA) GB or UKNI schemes are exempt from mandatory eCoC requirements and may continue to use paper CoCs on a permanent basis.

Not required yet: Category L, T, C, R and S vehicles are not subject to eCoC requirements at this time and should continue to use paper CoCs until further notice.

Here's the same information as a quick reference.

Category / scheme	eCoC requirement
M, N, O under GB or UKNI type approval	Mandatory from 29 November 2026
GB medium series	Subject to eCoC requirements
UKNI EU small series	Subject to eCoC requirements
National small series (NSSTA) GB or UKNI	Exempt, paper CoCs permitted permanently
Categories L, T, C, R, S	Not required at this time, continue paper

One caveat worth flagging: paper CoCs must continue to be provided free of charge at the point of sale where eCoCs are not provided. So the eCoC doesn't automatically kill the paper obligation in every case.

The key dates

There are two dates that matter most.

• 17 June 2026 is when the Phase 1 eCoC submission portal and API launched. So the tools for submitting data already exist.
• 29 November 2026 is the mandatory submission deadline for eCoCs for newly manufactured vehicles in the affected categories.

Crucially, there's no obligation to submit eCoC data for vehicles manufactured before 29 November 2026. The Department for Transport (DfT) has agreed to an extended transition period before that mandatory deadline, specifically to give manufacturers more time to get familiar with the VCA system. In other words, the gap between the June launch and the November deadline is a deliberate run-up, not dead time. If you're in scope, that window is when you build, test and iron out your submission process.

How the VCA's digital service is being built

The VCA is delivering a new digital service to handle the submission, storage and presentation of eCoC data, and it's arriving in two phases.

Phase 1 delivered three things: a new database for storing eCoC data, a web portal for manufacturers to manage and manually submit eCoC data, and an Application Programming Interface (API) service for automated transmission of data. As noted, this launched on 17 June 2026.

Phase 2 will deliver a public-facing webpage where anyone can locate and view the eCoC data of a vehicle that had an eCoC submission made, using the Vehicle Identification Number (VIN) as a unique identifier. Launch timings for Phase 2 are still to be confirmed. In the meantime, the VCA's guidance points to an 'Access to eCoC Data' section for how to get at eCoC data in the interim.

That two-phase split tells you something about priorities. Phase 1 is about getting data in and stored reliably. Phase 2 is about making it searchable and useful to the wider world. For a manufacturer, Phase 1 is the phase you have to engineer against right now.

The file format: XML, IVI 2.0 and UK-specific bits

This is where the eCoC stops being a document and becomes a data structure. The structure and content of UK eCoCs differ from what GB type approval legislation prescribes for paper CoCs, so you can't just digitise your existing sheet.

UK eCoCs are based on the Initial Vehicle Information (IVI) 2.0 file developed for the EU eCoC system. The UK IVI file follows the same structure and includes all content from the EU IVI file, with some additions to carry GB and UKNI specific approval information (for example, using 'g11' or 'n11' as an Approval Authority code for various fields).

IVI files must be in Extensible Markup Language (XML) format. The VCA publishes a copy of the XML Schema Definition (XSD) and a version control document for the UK IVI in the 'Publications' section of its page. Because the UK XSD was adapted from the EU equivalent, the EUCARIS guidance documents (including the 'messagebook' and 'IVI setup manual') stay relevant to the UK eCoC system and should be read alongside the UK-specific and supplementary guidance. More information on the EU eCoC system is available from EUCARIS.

The UK-specific IVI elements

The UK-specific parts of the initial UK IVI template are limited to extra data entry options (enumerations) for fields that have a restricted list of possible selections. Listed in the order they appear in the XSD file:

• "GeneralCodeEcoInnovationCode" adds eco-innovation code '99' as an option. This is a GB approved eco-innovation that doesn't appear in the EU list. Other GB eco-innovations use the same codes as the EU equivalents, as they do for UKNI.
• "TypeApprovalCountryCode" adds 'g11' and 'n11' options to the list of e?? codes.
• "TypeApprovalTypeCode" adds scheme options 'GBNSS' (GB national small series), 'GBMED' (GB medium series), 'GB' (GB unlimited series), 'UKNINSS' (UKNI national small series), 'UKNIESS' (UKNI European small series), and 'UKNI' (UKNI unlimited series) to the existing EU options.

Fields with EU references that stay

Because the UK template is aligned with the EU version, some fields keep EU-specific references. This doesn't stop you entering UK vehicle information, but the VCA gives supplementary guidance for clarity:

• "EURepresentativeGroup" should hold the name and address of the relevant GB-based (for GB type approvals) or EU/NI-based (for UKNI approvals) manufacturer's representative. If you're using a UK based representative, 'EURepresentativeCountryOfResidence' can list either 'Northern Ireland' or 'Great Britain' (as applicable), or 'United Kingdom', according to how the address is listed in type approval documents.
• "EUCountryCode" already has 'UK' as a selectable option, and that's what you use for UK eCoCs.
• "EULanguageCode" already has 'en' as a selectable option, and that's what you use for UK eCoCs.

The practical read here: your data has to map cleanly onto a schema that was designed for the EU and then extended for the UK. Where the schema uses an EU label, you follow the VCA's note on how to populate it with UK data. Getting these enumerations wrong is exactly the kind of thing that fails validation.

Who creates the files, and how

Creating the eCoC (UK IVI) XML files is the manufacturer's responsibility, or that of their authorised representatives. Importantly, the VCA does not provide software for generating eCoC files and does not mandate any particular commercial or open-source product. That's a deliberate hands-off stance: the regulator defines the schema and the submission routes, and leaves the file generation to you.

There's a wide range of publicly available information, XML tooling and software libraries you can use to create and validate files against an XSD. The VCA's advice is to pick an approach that fits your own systems and your volume of production. A manufacturer turning out a handful of vehicles has very different needs from one producing at scale.

As an alternative, manufacturers can use the EU manual input tool to generate an EU IVI XML file, then edit the output to reflect UK requirements (for example, adding GB- and UKNI-specific approval information where applicable). Whichever route you take, any file submitted to the VCA must conform to the UK IVI XSD published on the VCA page.

This is the part where, in our experience, projects quietly get more complicated than they first look. "Generate an XML file that matches a published schema" sounds simple. In practice, the data usually lives across your production systems, your type approval records and sometimes a spreadsheet or two, and it all has to be pulled together, mapped to the right IVI fields and validated before it's fit to send. If your source data currently sits in fragile spreadsheets, that's often the real bottleneck, and it's the sort of thing a bespoke tool that turns spreadsheets into proper software can solve for good.

The two ways to submit eCoC data

There are two routes for getting eCoCs to the VCA.

1. Manual file upload and submission via the VCA eCoC Portal.
2. System-to-system integration using an API.

The VCA expects option 1 to suit small volume manufacturers and option 2 to suit high volume manufacturers, but both are available and you choose based on preference. A VCA account is required for either method.

Once the VCA receives eCoC data, it's validated against the UK IVI XML schema to confirm the format is correct. If there are errors or issues with an uploaded file, you get feedback so you can correct and resubmit. That validation loop is the thing to design for: the goal isn't just to produce a file, it's to produce a file that passes first time, most of the time.

Manual portal versus API: which fits you?

Route	Best for	What it involves
Manual upload via eCoC Portal	Small volume manufacturers	Log into the portal, upload the XML file, act on any validation feedback
API (system-to-system)	High volume manufacturers	Automated transmission from your own systems, no manual upload per vehicle

If you're producing at volume, the manual route becomes a person clicking upload over and over, which is slow and error-prone. That's exactly the case for an integration that generates the file, validates it and pushes it to the API automatically. Building that kind of API integration and automation is squarely a software job, and it's the sort of work a team that handles custom integrations and internal tools takes on. If you'd rather not run it in-house, custom software and API integration work is one way to get the pipeline built and tested against the VCA's validation before November.

The eCoC Portal and accounts

The VCA eCoC Portal is the new digital service for submitting eCoC files and managing eCoC submission accounts. To use it, manufacturers need to create an account. Only manufacturers or their authorised representatives can create an account for eCoC submissions.

Once an account exists, manufacturers can assign additional users access to their accounts and manage user permissions. That's a small but useful detail if more than one person in your business will be handling submissions: you don't all share a single login, you manage proper user access.

What this means in practice, and how to prepare

Strip away the regulatory language and the job comes down to three things: get the data, shape it into valid UK IVI XML, and get it to the VCA in a way that scales with your volume. Here's a sensible order to tackle it.

1. Confirm your scope. Check your vehicle categories and approval schemes against the rules above. If everything you make is exempt or not-yet-required, you may have nothing to do beyond continuing with paper CoCs. If any of your output is category M, N or O under GB or UKNI, you're in.
2. Set up your VCA account early. You need one for both submission routes, and the portal and API have been live since 17 June 2026. There's no reason to leave account setup to the last minute.
3. Get the schema and read it against your data. Download the UK IVI XSD and version control document from the VCA's Publications section, and read the EUCARIS messagebook and IVI setup manual alongside the UK-specific guidance. Map every field you need to populate to where that data actually lives in your business.
4. Decide manual versus API. Base it on volume honestly. If you're generating more than a trickle of vehicles, the API route will pay for itself in saved time and fewer manual errors.
5. Build in validation before you submit. The VCA validates against the schema and sends back errors. You want to catch those on your side first, so submissions pass rather than bounce.
6. Use the transition window. The gap between June 2026 and the 29 November 2026 deadline exists precisely so you can get familiar with the system. Test with real data, fix what breaks, and don't treat November as the start date.

If your existing production and type approval data is scattered or held in spreadsheets that already creak, that's usually where the effort really lands. Pulling that together into something that reliably produces valid, submission-ready files is a proper piece of engineering, especially if you're going the API route. Whether you build it yourself or bring in help, start now while the transition period is on your side.

Need a hand turning your vehicle data into valid eCoC XML and getting it flowing into the VCA API before 29 November 2026? Our custom software and integration team builds exactly this kind of data pipeline and validation tooling. Get in touch and we'll scope it with you.