Much like its UK counterpart, it's written in Python using the Tweepy API. Mine scrapes data from Ireland's COVID-19 Data Hub and will tweet only when new data has been added. Annoyingly, this source data seems to lag behind the "headline" data that gets reported in the news, but I haven't found any better official source.
Like the UK bot, I'm counting percentages of adult (18+) population, those being what the government roadmap focuses on. This was an interesting challenge because there isn't really a solid source for the number of people older than 18 living in Ireland. The most recent census was 2016, so its data is about as out of date as it's going to get. It states the population as 4,761,865 but uses a fairly inconvenient set of age groups—13-18 and 19-24—which creates a bit of grey area.
In the end I estimated that about 1/6 of the 13-18 age group would be 18, giving an approximate over-18 total of 3,572,000 or 75% of the total population. The most recent official estimate of total population comes from the Central Statistics Office and places the population at 4,977,400 as of April 2020. Wanting to incorporate this growth, I used the 75% proportion from the 2016 data to land on 3,733,679 as the number that I base the 'progress' percentage off. If anyone knows of a better estimate, let me know!
To reflect some changes to the vaccine rollout in Ireland, I've now slightly modified the tracker to measure against the population aged 16 and over. Using the same method as above—just taking 1/2 of the 13-18 age ground instead of 1/6—I arrived at a new figure of 3,863,147 to base the percentage on.