Location
United States
Country level only
Domain
fastly.com
Served through Fastly's network, which answers from the location nearest each visitor.
Still looking this up. This tab fills in as the answers arrive.
Network Every network on the internet has an autonomous system number (ASN). This is the one that announces this address.
AS54113Fastly
Fastly, Inc.
BGP prefixPrefix The block of addresses this IP is announced in to the rest of the internet. RPKI valid means the block's owner signed off on the network announcing it.
RPKI valid151.101.128.0/22
Seen by 3,187 peers
Latency Round trip for an HTTPS request from your browser to the site and back, including the server's reply time.
Live— ms
Measuring from your browser…
At a glance
Route
Finding a probe near you…
Networks crossed
Each network is an autonomous system (AS). Your traffic is handed from one to the next where they connect, following
the routes BGP advertises.
- AS16509Anthropic, PBC
- AS54113Fastly
Tracing from a probe near you with Globalping. Hop locations that its round-trip times rule out are left off the map.
DNS records
TypeNameValueTTL
Afastly.com151.101.129.571 hr
Afastly.com151.101.1.571 hr
Afastly.com151.101.193.571 hr
Afastly.com151.101.65.571 hr
AAAAfastly.com2a04:4e42:400::3131 hr
AAAAfastly.com2a04:4e42::3131 hr
AAAAfastly.com2a04:4e42:200::3131 hr
AAAAfastly.com2a04:4e42:600::3131 hr
NSfastly.comedns1.ultradns.com1 hr
NSfastly.comns-cloud-a2.googledomains.com1 hr
NSfastly.comoak.fastlydns.com1 hr
NSfastly.comoak.fastlydns.dev1 hr
NSfastly.comedns1.ultradns.net1 hr
NSfastly.comns-cloud-a1.googledomains.com1 hr
NSfastly.comoak.fastlydns.net1 hr
NSfastly.comoak.fastlydns.org1 hr
MXfastly.com30 aspmx2.googlemail.com1 hr
MXfastly.com10 aspmx.l.google.com1 hr
MXfastly.com20 alt2.aspmx.l.google.com1 hr
MXfastly.com30 aspmx3.googlemail.com1 hr
MXfastly.com20 alt1.aspmx.l.google.com1 hr
TXTfastly.com"google-site-verification=XIAH8ONJreWlh9Y70OdOpJEOEJ2v2GQREV2tqq1CIRs"30 sec
TXTfastly.com"v=spf1 ip4:159.26.177.235 ip4:192.254.122.132 ip4:199.27.72.0/21 ip4:168.245.55.99 include:_spf.google.com include:_spf.salesforce.com -all"30 sec
TXTfastly.com"google-site-verification=PBhH4HrDEbENmggTOryS2QsbDGhnb9zc583U0CqYrm8"30 sec
TXTfastly.com"drift-domain-verification=cac9c53e6dcc8cfe8cadbbb83cb1b0b72a378ca58768fe368358e0a821a76c85"30 sec
TXTfastly.com"google-site-verification=93VjX3_sU9GM8VT_CBXHZvR1iRfWxDD8uVs-qcM-fa4"30 sec
TXTfastly.com"facebook-domain-verification=a5cr1f2db64tpngjvytpxe4u65sjtm"30 sec
TXTfastly.com"onetrust-domain-verification=ca990b1356924ce6a8f3db2b26470479"30 sec
TXTfastly.com"anthropic-domain-verification-90vjex=Jq3F6Vxk4FRdOFNIOSOq3NjDS"30 sec
TXTfastly.com"stripe-verification=a972553ccbc9121d3b1416aab829c8ee444e4f8bc38729e4ac75623c52b55ab3"30 sec
TXTfastly.com"_globalsign-domain-verification=Om8i6ZW5leojQ3EoMlITfDWE8mARIOyXkdjGp4f1AL"30 sec
TXTfastly.com"MS=ms21516267"30 sec
TXTfastly.com"atlassian-domain-verification=f0mlpbKMfaymWOzYknOWLAQ0a/f/hZbXof90UdM3pL2THIvc/nkCUTDoJusXl4kc"30 sec
TXTfastly.com"h1-domain-verification=tGLFu9vLa6oeUKtYgq3qPnbvWu43DZVdz1YQDXoNNFmSVn1Z"30 sec
TXTfastly.com"miro-verification=208c007cde2d4cda11ee84c49848d8b7074fba31"30 sec
TXTfastly.com"15c37408-29ae-4d52-8aac-c6f4d94fdcb7"30 sec
TXTfastly.com"mongodb-site-verification=emnlNQxedQspl3GSh4ZJP0LoDGoi07XT"30 sec
TXTfastly.com"dropbox-domain-verification=6qxhbsnj6ptn"30 sec
TXTfastly.com"MS=8DDEF0C8F0796A9B5250EF7D2BB6DE03C4556F6F"30 sec
TXTfastly.com"google-site-verification=r1uB8RIEL2lLC3Swp4-QBDrN-i9g-AK9YEjPUJN_6xU"30 sec
TXTfastly.com"docusign=b0d8d38f-fd39-4bf0-b916-609c0bd56e29"30 sec
TXTfastly.com"stripe-verification=b4b73bc8e56f0a7589ea23d1e9e2214cd20fff1c95bc1db244483af60d2a42f9"30 sec
TXT_dmarc.fastly.com"v=DMARC1; p=reject; rua=mailto:mailauth-reports@fastly.com,mailto:dmarc_agg@vali.email;"1 hr
CAAfastly.com0 issue "globalsign.com"1 hr
CAAfastly.com0 issue "amazonaws.com"1 hr
CAAfastly.com0 issue "letsencrypt.org"1 hr
CAAfastly.com0 issue "certainly.com"1 hr
CAAfastly.com0 iodef "mailto:security@fastly.com"1 hr
CAAfastly.com0 issue "digicert.com"1 hr
Protected from spoofing
Mail that fails its checks is rejected under fastly.com's DMARC policy, so forged mail doesn't reach inboxes.
- Receives mail
- Google Workspace
- Mail servers
- aspmx.l.google.comalt2.aspmx.l.google.comalt1.aspmx.l.google.com+2 more
- SPFLists the servers allowed to send mail for the domain. Receivers check it against the sending server.
- Rejects everything else3 of 10 DNS lookups · includes _spf.google.com, _spf.salesforce.com
- DMARCTells receivers what to do with mail that fails SPF and DKIM: nothing (none), spam folder (quarantine) or reject.
- Rejectsends reports
- MTA-STSRequires other mail servers to use encrypted connections (TLS) when delivering to this domain.
- Not published
- TLS reportsAsks other mail servers to report failed encrypted deliveries (TLS-RPT).
- Not requested
- BIMIA brand logo that some mail apps show next to authenticated mail from the domain.
- Not published
Details
Network
- IPv4
- 151.101.129.57
- ASNThe autonomous system number of the network that announces this address.
- AS54113
- Operator
- Fastly, Inc.
- CDNFrom the provider's own published list of its address ranges.
- Fastly
- PrefixThe block of addresses announced over BGP that contains this address.
- 151.101.128.0/22
- RPKIWhether a signed record (ROA) authorizes this network to announce this prefix.
- Valid
- VisibilityHow many bgp.tools peers carry this announcement.
- 3,187 peers
- Type
- Content
- Registry
- RIPE NCC
Location
Country level- Country
- United States
- Continent
- North America
Registration
RDAP- PopularityCloudflare Radar's ranking of domains by how often 1.1.1.1 users look them up.
- Top 5,000
- Registrar
- MarkMonitor Inc.
- Registered
- Jul 8, 200224 years ago
- Expires
- Jul 8, 2027in 8 months
- Updated
- Jun 15, 2026
- StatusRegistry flags on the domain, such as locks that stop unauthorized transfers or changes.
- Delete lockedTransfer lockedUpdate lockedDelete locked by registryTransfer locked by registryUpdate locked by registry
- DNSSECDNSSEC signs DNS answers so they can't be forged on the way to you.
- Unsigned
- Name servers
- edns1.ultradns.comedns1.ultradns.netns-cloud-a1.googledomains.comns-cloud-a2.googledomains.comoak.fastlydns.comoak.fastlydns.devoak.fastlydns.netoak.fastlydns.org
- Registrant
- Redacted for privacy
Jul 8, 2002269 days leftJul 8, 2027
HTTPS
Certificate
Valid- Issuer
- Certainly
- Issuing CA
- Certainly Intermediate R1
- Covers
- developer.fastly.com, fastly.com, www.fastly.com
- Also validOther unexpired certificates for this name, found in Certificate Transparency logs.
- 5 more certificates
Oct 4, 202623 days leftNov 3, 2026
From Certificate Transparency logs, via Cert Spotter.
Security
D- HSTSStrict-Transport-Security makes browsers refuse plain HTTP to this site. Preloaded sites are HTTPS-only even on a first visit.
- 1 year
- HTTP → HTTPSWhether the plain http:// address redirects visitors to the secure one.
- Redirects
- HTTP/3The newest HTTP, over QUIC. Announced in the alt-svc header or the domain's HTTPS DNS record.
- Available
- CAADNS records naming the only certificate authorities allowed to issue certificates for the domain.
- GlobalSign, Amazon, Let's Encrypt, certainly.com, DigiCert
- security.txtA standard file (RFC 9116) telling security researchers how to report vulnerabilities.
- Not published
Security headers 3 of 7
- HSTSpresent
- CSPmissing
- Framingpresent
- No sniffingpresent
- Referrermissing
- Permissionsmissing
- Isolationmissing
Response
200 OK1375 ms from CMH · 42.4 KBDNS lookup111 ms
301 fastly.com18 ms
200 www.fastly.com1375 ms
DNSConnect (TCP + TLS)Waiting for the replyFrom Cloudflare's CMH data center
Response headers
- connection
- close
- content-length
- 43414
- content-type
- text/html
- etag
- W/"3d3bc04c8f8ad0ca138e4fac9b721777"
- x-guploader-response-body-transformations
- gunzipped
- warning
- 214 UploadServer gunzipped
- fastly-restarts
- 1
- content-encoding
- br
- accept-ranges
- bytes
- date
- Mon, 12 Oct 2026 16:45:41 GMT
- x-served-by
- cache-sjc1000087-SJC, cache-cmh1290051-CMH
- x-cache
- HIT, HIT
- x-cache-hits
- 4, 1
- x-timer
- S1791823541.718921,VS0,VE1001
- vary
- Accept-Encoding
- x-xss-protection
- 1; mode=block
- x-frame-options
- DENY
- x-content-type-options
- nosniff
- set-cookie
- ff_revamp=experiment:100; domain=.fastly.com; path=/; max-age=2592000; SameSite=Lax; Secure
- cache-control
- max-age=0, must-revalidate
- server
- Artisanal bits
- server-timing
- ff-revamp;desc=experiment
- strict-transport-security
- max-age=31536000
- alt-svc
- h3=":443";ma=86400,h3-29=":443";ma=86400,h3-27=":443";ma=86400
Website
Page
Powering the best of the internet | Fastly
Fastly's edge cloud platform delivers faster, safer, and more scalable sites and apps to customers. Elevate your edge CDN, video delivery, security, and more.
- Language
- English
Built with
- CloudFrom the provider's published address ranges.
- Fastly
- CDN
- Fastlyx-served-by header
- Framework
- Astropage markup
Tech stack
Built with Each entry says what gave it away: a response header, a cookie's name, an asset's path or file name, or markup the tool leaves in the page. Versions are checked against endoflife.date's support schedules and, for JavaScript packages, OSV's vulnerability database, which carries GitHub's security advisories.
CDN & edge
- Fastly
x-served-by header
Framework
- Astro
page markup
Fonts
- TT Hoves Pro
self-hosted font
- Roboto Mono
self-hosted font
How it's made
- RenderingPrerendered pages are built ahead of time and served as files. Pages rendered on each request are built by server code for every visitor. Pages drawn in the browser arrive nearly empty and depend on JavaScript, which most AI crawlers don't run. Islands are interactive parts in otherwise static HTML.
- Complete HTML1,761 words before any script runs
- Edge cacheWhether a CDN or proxy answered heade.rs's request from its cache, and how long ago that copy was made (the Age header).
- Served from cacheFastly
- Cache-Control
- max-age=0, must-revalidate
- HTML
- 219.7 KB · sent Brotli-compressed
- Scripts
- 5 files · 17 inlineall from this site · 5 modules
Code from other sites Scripts a page loads from another domain run with the same power as its own code: they can read what visitors type and change the page. heade.rs checks what the HTML loads, not what tag managers add once they run.
The HTML loads no scripts from other sites.
AI & agents
Open to AI crawlers
robots.txt lets every AI crawler in.
Crawlers
Allows allTrainingSearchOn request
They visit a page when someone asks an assistant about it. ChatGPT's, Perplexity's, Meta's and Amazon's treat robots.txt as advisory;
Anthropic's and Mistral's follow it.
OpenAIGPTBotallowedOAI-SearchBotallowedChatGPT-Userallowed
AnthropicClaudeBotallowedClaude-SearchBotallowedClaude-Userallowed
GoogleGoogle-ExtendedallowedGooglebotallowed—
Microsoft—bingbotallowed—
AppleApplebot-ExtendedallowedApplebotallowed—
Perplexity—PerplexityBotallowedPerplexity-Userallowed
MetaMeta-ExternalAgentallowedMeta-WebIndexerallowedMeta-ExternalFetcherallowed
AmazonAmazonbotallowedAmzn-SearchBotallowedAmzn-Userallowed
MistralMistralAI-TrainingallowedMistralAI-IndexallowedMistralAI-Userallowed
OthersCCBotallowedBytespiderallowedDuckAssistBotallowed
- Can cite itThe AI products that can use the site in their answers: each answers from one crawler (OAI-SearchBot for ChatGPT search, Googlebot for AI Overviews, bingbot for Copilot), and robots directives on the front page, like noindex, nosnippet and noarchive, keep some out.
- ChatGPT searchClaudePerplexityAI OverviewsGeminiCopilotMeta AISiri
Reading
- Without JavaScriptText on the front page before any scripts run: what GPTBot, ClaudeBot, PerplexityBot and most agents read. Google, Bing and Apple's crawlers run scripts.
- 1,761 words
- MarkdownAgents like Claude Code, Cursor and OpenCode ask for Markdown in their Accept header. It's the page without its markup, so it costs them far fewer tokens.
- Not offered
- llms.txtA Markdown file listing a site's key pages for AI tools. Coding agents read it; search crawlers mostly don't.
- 87 links in 15 sections
- Structured dataschema.org JSON-LD in the page: facts about the site in a form machines read directly.
- Organization, Corporation
Tools Ways an AI agent can do things on the site, not just read it: an MCP server that apps like Claude, ChatGPT and Cursor connect to, an API catalog, packaged agent skills, a shopping profile (UCP), or tools the page offers AI in the browser (WebMCP). heade.rs looks in the official MCP Registry and the files the site publishes under /.well-known/.
No MCP server, API catalog, agent skills, shopping profile or in-page tools found.