API · /elements-api

Chemical Elements API

healthy 4,505 Subscribers

The complete periodic table as an API — all 119 chemical elements with their atomic and physical properties: atomic number and mass, category, phase, melting and boiling point, density, electron configuration, electronegativity, ionization energies and a short summary. Look up an element by symbol, atomic number or name, search and filter by category/phase/block, or fetch the whole table. Ideal for chemistry tools, education apps and science projects.

api.oanor.com/elements-api
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Machine-readable spec so AI agents can integrate this API.

/api/elements-api/openapi.json
/api/elements-api/llms.txt

Discovery: GET /api/index.json lists every API.

API health

healthy
Uptime
100.00%
Server probes · 24h
Avg latency
84 ms
Server probes · 24h
Subscribers
4,505
active
Total calls
380
last 7 days
status Full status page → · 16 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

Free

  • 1,500 calls / month
  • 3 requests / second
  • Hard cap (429 above quota, no overage)
  • 1,500 calls/month
  • 3 req/sec
  • Lookup + search + full table
  • No credit card
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Starter

€4.00 /month

  • 30,000 calls / month
  • 8 requests / second
  • Hard cap (429 above quota, no overage)
  • 30k calls/month
  • 8 req/sec
  • All filters
  • Email support
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Pro

€13.00 /month

  • 200,000 calls / month
  • 20 requests / second
  • Hard cap (429 above quota, no overage)
  • 200k calls/month
  • 20 req/sec
  • Education / app integration
  • Priority support
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Mega

€37.00 /month

  • 1,200,000 calls / month
  • 40 requests / second
  • Hard cap (429 above quota, no overage)
  • 1.2M calls/month
  • 40 req/sec
  • Embed in product
  • Dedicated SLA
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Built by

Related APIs

Other APIs with overlapping tags.

Crystallography API

Crystal structures as an API — powered by the Crystallography Open Database (COD), the open, public-domain collection of over 500,000 crystal structures of organic, inorganic, metal-organic compounds and minerals. Search the database by chemical formula (any standard casing — TiO2, Al2O3, H2O — is normalised automatically) or by free text over mineral names, titles and comments, then look up any structure to get its full crystallographic data: chemical and cell formula, space group (Hermann-Mauguin and Hall), the complete unit cell (a, b, c, alpha, beta, gamma and volume), the source publication (title, authors, journal, year, DOI) and a link to the CIF file. From quartz, calcite and diamond to anatase, corundum and diopside, it is ideal for materials science, solid-state chemistry, mineralogy, crystallography teaching and research tooling. This is a crystal-structure & materials database — distinct from molecule-property (chemistry / PubChem) and protein-structure (PDB) databases. Open data from the Crystallography Open Database (CC0 / public domain).

api.oanor.com/cod-api

Chemistry API

Chemical compound data as an API, powered by NIH PubChem (>100 million compounds). Look up any compound by common name, PubChem CID or SMILES and get its molecular formula, molecular and exact mass, IUPAC name, canonical SMILES, InChI and InChIKey, plus physicochemical properties (XLogP, TPSA, formal charge, hydrogen-bond donor/acceptor counts, rotatable bonds, heavy-atom count). List a compound's synonyms and trade/registry names, or resolve a name to PubChem CIDs. Ideal for cheminformatics, lab software, education, drug-discovery tooling and scientific data pipelines.

api.oanor.com/chemistry-api

Protein Interactions API

Protein-protein interaction networks as an API — powered by STRING, the database of known and predicted protein associations that combines evidence from laboratory experiments, curated pathway databases, gene co-expression, genomic context and automated text mining into a single confidence score, across thousands of organisms. Get a protein's top interaction partners (each with the combined confidence score and the seven evidence-channel subscores), the interaction network among any set of proteins as scored edges, and functional enrichment for a gene set — the over-represented GO terms, KEGG pathways, Pfam domains and more, each with its p-value, FDR and member genes. Pass gene symbols (TP53) or STRING/Ensembl ids, for human (default) or any species by NCBI taxon id. It is a cornerstone of systems biology — ideal for network analysis, functional genomics, pathway and bioinformatics tools. A protein-interaction-network resource — distinct from biological pathways (Reactome), curated protein complexes (Complex Portal) and Gene Ontology annotations (QuickGO). Open data from STRING (CC BY 4.0).

api.oanor.com/stringdb-api

Polygenic Scores API

Polygenic (risk) scores as an API — powered by the NHGRI-EBI PGS Catalog, the open database of published polygenic scores: weighted combinations of genetic variants used to estimate a person's genetic predisposition to a trait or disease. Search traits by name to find their ontology ids, list every polygenic score developed for a trait, and read a score's full metadata — the reported and mapped (EFO/MONDO) traits, the number of variants in the score, the development method, genome build, the ancestry distribution of the samples it was built and evaluated on, the publication behind it (title, journal, date, PubMed id), the release date, license and a direct link to the scoring file. From breast cancer and coronary artery disease to type 2 diabetes and BMI, it is ideal for statistical genetics, genomics, risk-prediction research and bioinformatics tools. A polygenic-score / genetic-risk-prediction resource — distinct from single-variant association studies (GWAS Catalog), population allele frequencies (gnomAD) and clinical variant interpretation (ClinVar). Open data from the NHGRI-EBI PGS Catalog (CC BY 4.0).

api.oanor.com/pgs-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Chemical Elements API?
Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Chemical Elements API with the x-oanor-key header. No credit card needed for the free tier.
What's the rate limit for Chemical Elements API?
Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.
How much does Chemical Elements API cost?
Chemical Elements API has a free tier with 100 calls / month. Paid plans start at €4.00 / month with higher quotas and faster rate limits.
Can I cancel my subscription anytime?
Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.
Is Chemical Elements API GDPR-compliant?
All requests to Chemical Elements API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Pick an endpoint from the list on the left to see its details and try it.

Code snippets

Sign up to get an API key, then call any path under your slug.

curl https://api.oanor.com/elements-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/elements-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/elements-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);
import requests
r = requests.get(
    "https://api.oanor.com/elements-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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