Licence, attribution, and what you may publish
Two different things are about to become public, and they are governed separately. Getting this wrong is the one mistake in this course that is hard to undo.
Your code and their data are not the same asset
The code is yours. You wrote it, or you generated it and reviewed it. Pick a licence and put it in the repository — a permissive one like MIT if you want it used, something more restrictive if you do not. A repository with no licence is not "open by default"; it is all-rights-reserved by default, which is rarely what an author intends.
The data is not yours. It is retrieved under your plan's terms, which are, in EODHD's own words, "intended for personal use only as commercial use requires a more thorough approach to licensing and data use".
So the honest artefact separates them. The starter repository does this with two files: a LICENSE covering the code, and a NOTICE that opens by saying the code licence "does not cover the market data this code retrieves". Copy that shape.
What you may and may not publish
| The code | Yes — that is the portfolio piece |
| A screenshot showing prices | Normal illustrative use |
Your .env.local |
Never |
| A cached copy of the price history | No — that is redistributing their dataset |
| Sample fixtures for tests | A handful of rows to make a test run is a different thing from shipping a dataset; keep it small and say what it is |
| A hosted instance serving other people from your key | This is the conversation to have with them first |
The last row is the one people arrive at without noticing. A deployed personal tool is personal use. The same deployment with a link you hand to twenty people is something else, and the difference is not technical.
Attribute the source
"Powered by EODHD APIs" in the footer and named in the README. It costs nothing, it is accurate, and it tells a reader where the numbers come from — which is information they need in order to judge them.
Say what it is not
One line, near the top: this is a research and learning tool, it is a historical and market-data viewer, it is not investment advice, and you are not a licensed adviser.
Course 3 argued this for backtests. It applies more broadly once anything is public, because a stranger has none of the context that makes your intent obvious. A chart with a rising line reads as a recommendation to almost everyone who sees it.
The finance behind it
What you may do with market data, treated properly from the data side: Where do you find the tickers that no longer exist? covers the same list this course tells you not to redistribute.
Try it now
Add both files and read your repository as a stranger would: can they tell what they may do with your code, and separately what they may do with the data it fetches? If either answer takes more than ten seconds to find, move it higher.