Question 1

Which is better, adresse.data.gouv.fr or GraphHopper Directions API?

Accepted Answer

If you need a Geocoding API that's easy to integrate, go with adresse.data.gouv.fr. adresse.data.gouv.fr uses no authentication while GraphHopper Directions API uses apiKey.

Question 2

What is the main difference between adresse.data.gouv.fr and GraphHopper Directions API?

Accepted Answer

adresse.data.gouv.fr: Address database of France, geocoding and reverse. GraphHopper Directions API: 
With the [GraphHopper Directions API](https://www.graphhopper.com/products/) you can integrate A-to-B route planning, turn-by-turn navigation,
route optimization, isochrone calculations and other .... They differ in authentication (no authentication vs apiKey), HTTPS support (yes vs yes), and CORS (unknown vs unknown).

Question 3

Which Geocoding API is easier to integrate?

Accepted Answer

adresse.data.gouv.fr is easier to integrate because it requires no authentication.

Feature	adresse.data.gouv.fr	GraphHopper Directions API
Authentication	None	apiKey
HTTPS	Yes	Yes
CORS	Unknown	Unknown

adresse.data.gouv.fr vs GraphHopper Directions API

adresse.data.gouv.fr

GraphHopper Directions API

When to use which?