What the GRN is
Every participant on diidum Events has a Global Race Number — a permanent, unique identifier that follows them across every event, every year, for as long as they want it.
The format is simple: a country prefix, a hyphen, and six digits. Ireland uses IE. Numbers are assigned in order, so the first runner in the diidum system was IE-000001, the thousandth was IE-001000, and so on.
IE-004721 belongs to one runner. It always will. They will see it on their bib at every diidum-powered event they enter, on their profile when they log in, and in the result of every race they finish.
The GRN is assigned automatically the first time someone registers for a diidum event. There is no separate sign-up, no membership fee, and no opting in. If you have ever entered a race through diidum, you already have a GRN — it is on your dashboard at my.diidum.com waiting for you.
The problem the GRN solves
Race day is run on data. The timing company records who crossed the line and when. The registration platform records who entered and what they paid. After the race, those two records have to be matched together so each runner gets their result.
In Irish road running, that matching is usually done by name. And that is where it falls apart. A field of 700 might have a dozen Murphys, eight Kellys, and six Brennans. Add spelling variations (Seán / Sean / Shawn), maiden names, club secretaries registering on behalf of members, and runners using one email at sign-up and another in everyday life — and matching results by name becomes hours of manual work, with mistakes that surface as polite-but-frustrated emails the following week.
The current way to deal with all of this is manual. After the race, a volunteer sits down with two spreadsheets and works through them line by line. Two to four hours per event, every event. The GRN exists to make that process unnecessary.
How a GRN-enabled race works
The eight steps of a GRN-enabled race
- A runner registers for an event through diidum. The first time they register, they are assigned a GRN automatically (for example IE-004721). Returning runners use the GRN they already have.
- The organiser assigns bib numbers — typically a few weeks before race day. Each runner’s bib is now linked to their GRN in the diidum database.
- The organiser exports the start list. The export is a single file that includes the bib number, the runner’s name, and their GRN, all in one row per runner.
- The organiser sends the start list to the timing partner. No reformatting, no merging of files, no last-minute manual lookups.
- On race day, the timing partner records bib numbers and chip times. The bib-to-GRN link is already known, so every chip time is now associated with a permanent runner identity, not a fragile name string.
- After the race, the timing partner uploads the results to diidum — either as a CSV or via a single API call. The matching is exact and instant. No name deduplication is required.
- Each runner’s result appears in their diidum account automatically. They get an email; they log in to my.diidum.com; their result is there.
- The same GRN is used at the runner’s next event, regardless of which organiser, which county, or which timing partner runs it. Their lifetime race history grows automatically.
That is the whole picture. The audience-specific tabs above go into more detail on what changes for runners, organisers and timing partners.
For runners
If you have entered a road race or a charity 5K through diidum, you already have a GRN. This section explains what it gives you and how to use it.
What you get on day one
The first time you log in to my.diidum.com, your GRN is shown on your dashboard. It looks like IE-004721 — a country prefix and six digits. That number is yours. It does not change. You do not need to renew it, pay for it, or do anything to keep it.
Your dashboard also shows you any events you are registered for, any results that have been published for you, and your personal bests at each distance you have run. If you have only run one race so far, the dashboard will be modest — but it grows automatically with every event you enter.
What changes at your next race
Once your GRN is on the start list, your race day experience changes in three small but cumulative ways:
- Your bib has your GRN printed on it. Some runners notice this immediately, others not at all. Either is fine. The GRN on the bib is for the timing partner and the result-matching process — runners never need to write it down or remember it themselves.
- Your result appears in your account automatically. There is no form to fill in, no email to reply to, no spreadsheet to wait for. When the timing partner uploads the results, they appear under your GRN and in your dashboard.
- Your race history accumulates without effort. Each new result joins the previous ones. Your personal bests update if you run faster. Your dashboard becomes a record of your running, kept by the platform rather than by you.
The GRN is designed to be invisible to the runner who just wants to run. It does its work in the background. You do not need to think about it for it to benefit you.
The longer-term value
The everyday usefulness of the GRN — automatic results, automatic personal bests — is real and immediate. The longer-term value takes a year or two to become apparent, but it compounds. After three years on diidum, a runner has:
- A complete record of every event they entered through the platform — date, distance, location, time, and category position.
- Verified personal bests at each distance they have run, with the date and location of each.
- A profile they can share with a coach, a club secretary, or a registration form that asks for past performance.
- Year-on-year progression visible at a glance — useful for training, for goal-setting, and simply for the satisfaction of seeing improvement.
None of that requires the runner to do anything beyond keep entering races. The platform builds the record.
If you were registered by someone else
Some runners enter races through a club secretary, a family member, or a friend who registers a group together. In those cases, you may already have a GRN that you have not yet claimed.
Claiming your GRN is a one-time process. Go to my.diidum.com/claim, enter the GRN that is printed on your bib, enter your name as it was registered for the event, and provide your own email address. We send you a sign-in link, and from that point forward your GRN belongs to you and is associated with your own email address.
Privacy and what we do not do
The GRN is an identifier within the diidum system. It is not a national ID, a sporting licence, or a database record shared with any external body. We do not sell it. We do not pass it to advertisers. We do not require you to use it outside diidum events.
Your race results are visible by default to anyone who looks up your runner profile, in the same way that any race result published on a Facebook page or a results PDF is visible. You can make your profile private in your settings if you prefer. If you no longer want a GRN, you can request deletion at — we will remove your account and your GRN will be retired (not reissued to another runner).
For race organisers
The GRN is a tool for you as much as it is an identity for your runners. This is the longest section on the page because the GRN changes the most parts of an organiser’s job.
What the GRN replaces
Most race committees in Ireland already have a working post-race process. It usually involves a registration spreadsheet, a results file from the timing partner, and a volunteer who spends the evening after the race lining them up against each other. The GRN replaces that process with one that is fast, accurate, and does not require a volunteer.
The specific things the GRN replaces are:
- The post-race name-matching session — typically two to four hours of cross-referencing two spreadsheets, with mistakes that lead to follow-up correction emails the following week.
- The follow-up correction process — emails from runners whose times got attributed to someone else, or who do not appear in the published results at all.
- The patchwork start list — a registration export hand-edited into the format the timing partner needs, often as a last-minute job the night before the race.
- The fragmented record of past participants — a different spreadsheet for every year, with no easy way to recognise returning runners or see who registered last year and has not registered this year.
What changes in your registration export
This is the practical heart of it. When you register an event with diidum, every confirmed participant has a GRN. Your registration export includes a GRN column alongside the standard name, email, phone, distance, and emergency contact fields.
The export is also the start list. There is no second file to prepare for the timing partner. The same export — or a slightly trimmed version that excludes email addresses and other personal details — goes straight to whoever is timing your race. The timing partner can match results to runners by GRN without seeing your participants’ personal data, which is a cleaner GDPR position than sharing full registration files.
diidum offers three default start list views: an Admin view with everything, a Check-in view with what you need at the registration desk, and a Timing view with the minimum a timing partner needs. The GRN appears in all three.
Returning runners and your event year-on-year
The GRN turns a runner into a stable record across years. A runner who entered your 2025 event and your 2026 event is the same person in the database, even if they used a different email address or a slightly different name on each registration. That gives you something most Irish committees do not have today: a real picture of who is coming back and who is new.
Concretely, you can look at your event and see:
- How many of this year’s entrants ran your race last year, and how many are new.
- Which runners have entered three years in a row and might appreciate a thank-you note.
- Which clubs are growing their attendance at your race over time.
- Demographic shifts year over year — distance preference, age profile, gender split — without manually deduplicating spreadsheets to get there.
None of this is essential for running a race. All of it is useful when you are reporting to your committee, your sponsors, or your local authority on how the event is doing.
Day-of entries and walk-ups
Day-of entries — a runner who turns up on race morning, pays their fee, and enters on the spot — get a GRN like everyone else. The diidum check-in workflow lets a volunteer enter a name, a contact phone, a distance, and a payment, and the GRN is assigned automatically. The walk-up runner appears in the start list, the timing partner sees them, and their result lands in their dashboard if they later claim their account.
Refunds, cancellations, and changes
A runner’s GRN is independent of any particular registration. If they enter, then cancel, then re-enter the same event two weeks later, they have one GRN throughout. If they enter the 5K, then change to the 10K, they have one GRN throughout. The clean separation between the runner’s identity and the registration record simplifies every scenario where a registration gets adjusted.
What the GRN does not do for you
It is worth being honest about the things the GRN is not. It is a participant identifier, not a magic wand.
- The GRN does not chase up incomplete registrations. If a runner does not provide a date of birth at sign-up, the GRN cannot fill it in.
- The GRN does not eliminate the need to talk to your timing partner. You still need a working relationship with whoever is chip-timing your race.
- The GRN does not make a result accurate that was inaccurate at the timing chip level. If the timing partner’s chip mat misreads a bib number, the GRN cannot recover the missing data — but neither can any other system.
- The GRN does not currently work for runners outside the diidum platform. A non-diidum runner who turns up at your event will need to be registered as a day-of entry or matched manually after the race.
None of these are gaps we plan to leave open forever. The first three are inherent limits of any registration system; the fourth is the natural growth ceiling of the GRN, which expands as more events use it.
For timing partners
This section is shorter than the runner and organiser sections, but the change for timing partners is the most direct: you save time on every race, and you offer your clients a cleaner result delivery process. It is a small ask in exchange for a meaningful reduction in post-race effort.
What we are asking of you
The minimum integration is two small additions to your existing workflow:
- Include the GRN column in your start list. When an organiser sends you a diidum start list, the GRN is already there as one of the columns. You do not need to fetch it, generate it, or modify it. You just need to keep it in your file when you load runners into your timing software.
- Upload results to diidum after the race. This can be a manual CSV upload through the organiser portal or a single API call from your timing software. Either way, the upload includes bib numbers and times — diidum matches them to GRNs and delivers results to runner accounts.
That is the whole integration. The total additional time per event is under five minutes. In exchange, you eliminate the most time-consuming and error-prone part of post-race work: deduplicating common Irish names against a registration list.
We are not asking you to change your timing platform, your hardware, or your core workflow. The GRN is a column in a CSV — small enough that it can be added without reworking anything you already do well.
The Results API
Timing partners who want a deeper integration can use the diidum Results API. It is a REST API with a single primary endpoint for results upload, plus secondary endpoints for downloading start lists, validating result files before publishing, and looking up individual runners by GRN.
Authentication is per-partner with a token generated in the diidum portal — there is no shared key, no manual coordination, and no requirement to store sensitive credentials in our system or yours. A typical post-race upload is a single POST request with a JSON body containing the bib numbers, chip times, and gun times. For a 700-runner field, the entire upload takes seconds.
What you get out of it
The most direct benefit is the time saved on each event. Two to four hours of manual name-matching becomes a single upload. Across a season, that adds up materially — and it is time spent on the part of the work that creates real value, not on data cleanup.
The less obvious benefit is the differentiation you can offer your clients. An organiser choosing between two timing partners has a tangible reason to pick the one that delivers results to their participants automatically. “Results in your account before you finish your warm-down” is a story any committee will repeat to the next committee.
And there is a longer-term position worth considering. As the GRN becomes the standard identifier for Irish road running, timing partners who already work with it will be the obvious choice for any event that has adopted diidum. We are not asking for exclusivity — we are saying that early support for the standard is rewarded.
Pilot events and getting started
The simplest way to evaluate the GRN is to run one event with it. We are happy to set up a pilot event with full technical support — we provide the start list in the format you need, walk through the results upload, and handle any edge cases together. After one event, you have a clear picture of what changes and what does not.
To start a pilot conversation, email . The pilot itself takes no preparation beyond agreeing on which event you want to use; we do the rest.
Common questions
Questions that come up most often across all three audiences. If yours is not here, the answer is at — we read every message.
Why a six-digit number? What happens after the millionth runner?
Six digits gives us up to 999,999 GRNs in Ireland, which is comfortable headroom for the next decade and beyond. If we do approach the limit, we extend the format — existing GRNs remain valid, and the change is invisible to runners who already have one. Permanence comes first.
Can I take my GRN to a non-diidum event?
Today, the GRN is recognised at events that use diidum for registration or timing. We are working with timing partners individually to extend recognition, and over time the GRN will become a national standard rather than a platform-specific one. For now, the practical answer is: at a diidum event, your GRN works; at a non-diidum event, you may need to register separately. As more partners adopt the GRN, this gap closes.
Is there a cost to runners?
No. The GRN is assigned automatically when you first register for an event and there is no separate fee. There is no premium tier, no membership upgrade, and no plan you need to sign up for. The GRN is part of the platform that organisers pay for; runners use it at no cost.
What if I have two GRNs by mistake?
It happens occasionally — usually because a runner registered with a different email address one year and the system created a second account. Email with both GRNs and we will merge the accounts. The result history from both is preserved; you keep the GRN that was assigned first.
How is this different from an Athletics Ireland licence?
An Athletics Ireland licence is a sporting registration with a national governing body. A GRN is a participant identifier within the diidum events platform. The two are complementary and serve different purposes — your AI licence proves you are a registered athlete; your GRN ensures your race results land in your account. We are in early conversations with Athletics Ireland about how the two systems might work together more directly in future.
What happens to my GRN if diidum stops operating?
Our commitment is that runners can export their full race history at any time, in a format they can take elsewhere. The GRN itself only has meaning within diidum, but the data tied to it — your results, your personal bests — is yours to keep. If we ever wound down the platform, we would publish a clear migration path well in advance.
As an organiser, what do I need to do to enable the GRN at my event?
Nothing additional, beyond registering your event with diidum. The GRN is on by default for every diidum event. Your registration export already includes the GRN column. Your start list export already includes it. Your participants already have one. There is no separate setup, no additional cost, and no opt-in step.
As a timing partner, do I have to use the GRN to work with diidum-registered events?
No. You can continue to receive a name-based start list from a diidum organiser and deliver results back the way you do today. The GRN is optional from your side — but adopting it removes the manual matching step at the back end of every race, so most timing partners find it pays for itself within one or two events.
How do I find my GRN if I have lost track of it?
Sign in to my.diidum.com with your registration email. Your GRN is on your dashboard. If you cannot remember which email you used, email and we will help you find your account.