ETag
Declared by 147 providers across 13018 published specification files in the APIs.io network.
Spelled 4 ways
HTTP field names are case-insensitive (RFC 9110 §5.1), so every spelling below is the same header on the wire. A contract is not the wire: generated clients key off the string, and a developer reading two of these sees two different headers.
ETagetagEtageTag
Reached by regulation
Carried by the fhir standard.
The registry
| Status | permanent |
|---|---|
| Reference | RFC 9110, Section 8.8.3: HTTP Semantics |
Providers declaring it (147)
acoustic adobe-suite adp aib-group-uk aimlapi akamai aldermore algolia amazon-cloudfront amazon-s3 apache-iceberg apache-ozone azure-storage-accounts bank-of-ireland-uk bank-of-scotland barclays bitpowr-technologies-inc blng bread-financial brightcove btc-war-live-market-data-api cadasto canonical ccp-games cdr-energy cerner chargy cint citi cloudflare-r2 co-operative-bank commure companies-house continuous-delivery-foundation coventry-building-society cubefs cybersource cyclecalcs dapr dedaluslabs devcycle dotdigital eclipse elastic-path electric-sql equinix etsi euronet eve-online fenergo fhir figshare filebase first-direct fusebit galileo-technologies game-of-thrones gb-bank glide-apps halifax here humanitec igaming-tools ilert indykite influxdata influxdb interhyp jp-morgan-chase keboola lakefs lakekeeper leeds-building-society lloyds-banking-group mastercard metro-bank mettle microsoft-azure microsoft-azure-batch microsoft-azure-devops miro monument-bank nasuni nationwide-building-society nedap newstore newtqnia nhost open-banking-uk openehr openfeature openmercantil oracle oracle-cloud oracle-database oracle-partitioning oracle-platforms orion-health osmaura pagesnap palo-alto-networks paragon-bank planomy-tax-data principality-building-society pypi qliksense qr-code-crafter recognise-bank rhombus-systems salesforce santander-uk secure-trust-bank seven-bridges shawbrook-bank shyft sigstore six-group skipton-building-society smarty soracom sovrn spp stanford starling-bank subspace symphony synack tago-io tsb-bank uclouvain university-of-washington uphold upwind vendasta viglink virgin-money-uk wazo weatherbys-bank wikidata wikimedia wikipedia wikisource worklittle worldcat wso2 zhejiang zoominfo
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All headers Conditional Requests & Concurrency Guidance on headers.apievangelist.com
Work with this as data
Every header here is available over the APIs.io API and to AI agents over MCP. HTTP Headers is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.