Skip to content
Chempirical logovsLaunch Library 2 logo

Chempirical API vs Launch Library 2 API

Two free Science & Math APIs compared on access, reliability and developer ratings, using data from our daily health checks.

The verdict

  • Choose Chempirical API if you want faster responses.
  • Choose Launch Library 2 API if its data fits your use case better; on access and reliability it's level with Chempirical API.

Side by side

Chempirical APILaunch Library 2 API
What it doesChemical compounds with physical data, reactions and substructure search.Spaceflight launches and events database.
ProviderChempiricalTheSpaceDevs
API keyNot neededNot needed
HTTPSYesYes
CORS (browser calls)YesYes
Status todayOnline · 533 msOnline · 876 ms
Uptime (30 days)UpUp
Developer ratingNot rated yetNot rated yet
PriceFree / free tierFree / free tier
Chempirical docs ↗Launch Library 2 docs ↗

About each API

Chempirical logoChempirical API

Chemical compounds with physical data, reactions and substructure search.

Free read-only JSON API for 48,000 compounds, reactions, Antoine constants and azeotropes: search, identifiers, physical data, structure images and reaction scaling.

Strengths

  • No API key needed
  • Callable from the browser (CORS)
  • HTTPS

Ratings, reviews and FAQ →

Launch Library 2 logoLaunch Library 2 API

Spaceflight launches and events database.

A group of space enthusiast developers working on services to improve accessibility of spaceflight information.

Strengths

  • No API key needed
  • Callable from the browser (CORS)
  • HTTPS

Ratings, reviews and FAQ →

How to choose between them

  • Prototyping or a tutorial? Pick the one that needs no API key (both qualify).
  • Calling from a web page? You need CORS. Otherwise route requests through your own server or a serverless function.
  • Going to production? Favour HTTPS, a strong uptime record and a provider with clear rate limits and terms. Check each API's docs before you commit.
  • Still unsure? Both are free to try: send one request to each and compare the data you get back.

Chempirical vs Launch Library 2 FAQ

Do Chempirical API and Launch Library 2 API need an API key?

Neither needs an API key; you can call both straight away.

More comparisons

Chempirical API alternatives · Launch Library 2 API alternatives · best Science & Math APIs