Networking & developer utilities
DNS, certificates, IP, email and everyday developer utilities. Fast, private and ready for production.
- 148tools ready49 more coming
- 21categoriesA to Z
- 25public resolvers5 regions
- 8DNS record typesA to CAA
- 0trackersno ads
- 1placefor everything
Toolbox
Pick a tool.
Get answers in seconds.
Network diagnostics, security checks and developer helpers, grouped by category and sorted A to Z.
197 tools · 21 categories
cURL Converter
Turn a curl command into fetch, Python, Go or PHP code.
- Soon
GraphQL Tester
Send queries, explore the schema and see timings.
- Soon
HTTP Request Builder
Send any method, headers and body and see the full response and timings.
- Soon
OpenAPI Viewer & Validator
Browse and validate an OpenAPI or Swagger spec, in your browser.
Webhook Tester
A private URL that records every request sent to it.
Certificate ↔ Key Matcher
Check a certificate, key and CSR belong together, without uploading the key.
Certificate Chain Fixer
Find missing intermediates and build the correct bundle.
Certificate Decoder
Read the subject, issuer, SANs and expiry from a PEM certificate.
CSR Decoder & Generator
Inspect a certificate signing request or create a new one.
HMAC Generator
Sign messages with HMAC-SHA256 and friends to test webhooks.
Key Pair Generator
Create RSA, EC or Ed25519 keys in your browser; they never leave it.
Password Generator
Strong random passwords and passphrases, generated in your browser.
PEM ↔ DER ↔ PKCS#12 Converter
Convert certificates and keys between common formats.
PGP Key Inspector
See a PGP key's IDs, subkeys, expiry and algorithms.
Revocation Checker (OCSP / CRL)
Check whether a certificate has been revoked.
Self-Signed Certificate Generator
Make certificates for labs and local development.
SPKI Pin Generator
Create public-key pins for apps and HPKP-style configs.
SSH Key Fingerprint
Get the SHA-256 and MD5 fingerprints of an SSH public key.
TOTP / 2FA Tester
Generate and check time-based one-time codes from a secret.
- Soon
CDN Detector & Cache Checker
See which CDN serves a URL and whether it’s cached, for how long and why.
- Soon
Cloud Egress Cost Calculator
Compare data transfer costs across AWS, Google Cloud, Azure and Cloudflare.
- Soon
Cloud IP Range Lookup
Find out if an IP belongs to AWS, Google Cloud, Azure, Cloudflare or GitHub.
- Soon
Cloud Region Latency
Measure latency from your browser to cloud regions around the world.
- Soon
S3 / R2 Presigned URL Generator
Create time-limited download and upload links for S3-compatible storage, in your browser.
Case Converter
Switch text between camelCase, snake_case, kebab-case and more.
Diff Checker
Compare two texts side by side with changes highlighted.
HTML Entity Encoder
Encode and decode HTML entities and Unicode escapes.
Image ↔ Base64
Turn images into data URIs and back.
Image Optimizer
Resize, compress and convert images to WebP, AVIF or PNG, in your browser.
JSON ↔ YAML ↔ CSV
Convert structured data between JSON, YAML and CSV.
Line Tools
Sort, dedupe, reverse, shuffle, trim and prefix lines of text.
Markdown Preview
Write Markdown and see the rendered result as you type.
Markdown Table Generator
Turn CSV into Markdown, HTML or ASCII tables.
Number Base Converter
Convert numbers between binary, octal, decimal and hex.
SVG Optimizer
Clean up and minify SVG files.
Text Statistics
Count words, characters and lines, and find duplicate lines.
Time Zone Converter
Convert times between zones and find a meeting time that works.
XML Formatter & XPath
Format XML and test XPath queries against it.
- Soon
Connection String Builder
Build and parse Postgres, MySQL, SQL Server, MongoDB and Redis connection strings.
- Soon
Database Size Estimator
Estimate table and index size from columns, rows and fill factor.
SQL Formatter
Format and minify SQL for common dialects.
Base32 / Base58 / Ascii85
Encode and decode the less common base encodings.
Base64 Encode/Decode
Convert text and files to and from Base64 and Base64URL.
Color Converter
Convert HEX, RGB, HSL and OKLCH, and check contrast.
JSON → TypeScript / Go / Python
Generate type definitions from a JSON sample.
JSON Formatter
Format, validate and minify JSON with clear error positions.
Lorem / Fake Data Generator
Names, emails, IPs and UUIDs for testing, as JSON or CSV.
QR Code Generator
Make QR codes for links, Wi-Fi details and contact cards.
Regex Tester
Test regular expressions with live match highlighting.
Semver Calculator
Test version ranges like ^1.2.3 against a list of versions.
Timestamp Converter
Convert between Unix time, ISO 8601 and your local time zone.
URL Encoder
Encode, decode and parse URLs and query strings.
UUID Generator
Generate v4 and v7 UUIDs in bulk.
.env ↔ JSON / YAML
Convert environment files and flag duplicate or empty keys.
Caddy / HAProxy Config Generator
Generate Caddy and HAProxy configs for common setups.
chmod Calculator
Convert between symbolic and numeric Unix file permissions.
Compose → Kubernetes
Convert docker-compose files to Kubernetes manifests.
Cron Explainer
Turn cron expressions into plain English and see the next run times.
Docker Run → Compose
Convert docker run commands into a docker-compose.yml file.
Dockerfile Linter
Spot common Dockerfile mistakes and suggest best practice.
GitHub Actions Linter
Spot workflow mistakes, unpinned actions and risky triggers.
htpasswd Generator
Create bcrypt or APR1 password entries in your browser.
iptables / nftables / UFW Builder
Write a firewall rule once and get it in all three formats.
Kubernetes Manifest Generator
Build Deployment, Service, Ingress and HPA manifests from a form.
logrotate Generator
Build log rotation config with sensible defaults.
Nginx Config Generator
Generate server blocks for reverse proxies, TLS and redirects.
SSH Config Generator
Create ~/.ssh/config entries, including jump hosts.
systemd Unit Generator
Build a service file with sensible hardening defaults.
User-Agent Parser
Identify the browser, OS and device from a user-agent string.
YAML / Kubernetes Validator
Validate YAML and catch common Kubernetes manifest mistakes.
CAA Records
See which certificate authorities are allowed to issue for a domain.
Dangling DNS / Takeover Checker
Find CNAMEs pointing at deleted cloud resources someone else could claim.
dig
Run dig-style queries against any server, with +trace, DNSSEC and the raw answer, authority and additional sections.
DNS Lookup
Query A, AAAA, MX, TXT, CNAME, NS and SOA records from any resolver.
DNS Propagation
See whether a record change has reached resolvers around the world.
DNS Record Generator
Build SPF, DMARC, CAA, SRV and TXT records from a simple form.
DNS Resolver Benchmark
Compare the speed and reliability of public DNS resolvers.
DNSSEC Validator
Verify the DNSSEC chain of trust from the root down to your zone.
DoH / DoT Tester
Check a DNS-over-HTTPS or DNS-over-TLS resolver works and validates DNSSEC.
MX / Mail Routing Lookup
See MX records by priority with their IPs and reverse DNS.
NS / Zone Health Check
Check nameservers agree, glue records, lame delegation and SOA serials.
Punycode / IDN Converter
Convert internationalised domain names and spot lookalike characters.
Reverse DNS (PTR)
Find the hostname behind an IP address and check it matches forward DNS.
Subdomain Finder
Discover subdomains from public Certificate Transparency logs.
WHOIS / RDAP
Registrar, expiry dates and nameservers for any domain or IP block.
Zone File Validator & Converter
Check a BIND zone file and convert it to and from CSV or JSON.
Abuse Report (ARF) Parser
Read spam complaint reports from feedback loops.
BIMI Checker
Check your BIMI record and logo so your brand shows in inboxes.
Bulk Sender Requirements
Check a domain against Gmail and Yahoo's bulk sender rules.
DKIM Key Rotation Planner
Plan selectors, new records and when to retire old DKIM keys.
DMARC Report Viewer
Read aggregate DMARC XML reports, zipped or not, as clear charts.
Email Address Validator
Check syntax, MX, disposable domains and role accounts without sending mail.
Email Blocklist Check
See whether a mail server IP or domain is on a spam blocklist.
Email Header Analyzer
Trace a message’s path and delays from its raw headers.
List-Unsubscribe Checker
Validate one-click unsubscribe headers (RFC 8058).
MTA-STS & TLS-RPT Checker
Check the MTA-STS policy file, its DNS records and TLS reporting.
SMTP Test
Connect to a mail server and check its banner, STARTTLS and response.
SPF / DKIM / DMARC
Validate your email authentication records and spot misconfigurations.
SPF Flattener
Replace include: chains with IP lists to stay under the 10-lookup limit.
- Soon
Cable Label Generator
Make printable patch and cable labels from a list or a numbering pattern.
PoE Budget Calculator
Add up device power draw against a switch's PoE budget.
- Soon
Power & Heat Calculator
Watts, amps, VA and BTU/hr for a room or rack, and the cooling it needs.
- Soon
Rack Planner
Lay out kit in a rack by U, with weight and power per device.
- Soon
UPS Runtime Calculator
How long a UPS keeps your load running.
JWT Decoder
Decode and verify JSON Web Tokens locally, without sending them anywhere.
JWT Generator / Signer
Build and sign test JSON Web Tokens.
- Soon
LDAP DN & Filter Builder
Build and check distinguished names and search filters, with escaping.
- Soon
OIDC / OAuth Discovery Checker
Validate an OpenID Connect discovery document and its keys.
- Soon
Password Policy Generator
Turn NIST 800-63B guidance into settings for Linux, Windows, Entra ID and apps.
- Soon
SAML Response Decoder
Decode SAML assertions and inspect signatures and attributes.
ASN → Prefix Allowlist
Turn every prefix a network announces into firewall or nginx allow rules.
ASN Lookup
Owner, country and announced prefixes for any autonomous system.
BGP Looking Glass
See how routers around the world see a prefix.
BGP Prefix Lookup
See which network announces a prefix and its upstream peers.
Bogon Checker
Find out whether an address or prefix should never appear on the internet.
Bulk IP Lookup
Owner, country and ASN for hundreds of IPs at once, with CSV export.
IP Address Converter
Switch an IP between dotted, decimal, hex, binary and IPv4-mapped forms.
IP Range ↔ CIDR
Turn a start and end address into the smallest set of CIDR blocks.
IP Reputation
Check an IP against public abuse and spam blocklists.
IPv6 Address Generator
Make EUI-64, privacy and ULA addresses and plan IPv6 prefixes.
IPv6 Expand / Compress
Switch IPv6 addresses between full and shortest notation.
My IP & Geolocation
See your public IP, ASN, ISP and approximate location.
RPKI / ROA Validator
Check whether a prefix and origin AS are covered by a valid ROA.
- Soon
Grok & Log Pattern Tester
Test grok and regex patterns against log lines and see the fields.
Log Analyzer
Top IPs, status codes, slow URLs and bots from an access log, in your browser.
- Soon
PromQL & Alert Rule Builder
Write Prometheus queries and alerting rules from common patterns.
- Soon
Syslog Parser
Decode RFC 3164 and 5424 syslog lines, facility and severity.
Certificate Expiry Tracker
Watch your hosts' certificates and get warned before they expire.
- Soon
DNS Change Monitor
Snapshot a domain's records on a schedule and see what changed.
Domain Expiry Tracker
Know when domains are due to expire before they lapse.
IP Blocklist Monitor
Watch your mail server IPs and get flagged as soon as one is listed.
- Soon
Ping Monitor
Scheduled pings with latency, jitter and packet-loss history.
Uptime Monitor
Scheduled checks of your sites with a response-time history.
- Soon
DHCP Options Builder
Build option 43, 121 and 66/67 values for access points, routes and PXE.
- Soon
DSCP / QoS Reference
DSCP, ToS and CoS values with common traffic classes.
- Soon
iperf3 Throughput Test
Test TCP or UDP throughput from NetKit to a public or your own iperf3 server, and build iperf3 commands.
MAC Vendor Lookup
Find the manufacturer behind any MAC address or OUI prefix.
Network Path MTU Test
Find the largest packet that reaches a host without fragmenting.
NTP Checker
Query an NTP server for its time offset, stratum and reachability.
- Soon
PCAP Viewer
Summarise a packet capture by protocol, conversation and DNS query, in your browser.
Ping & Latency
Measure round-trip time and packet loss to any host.
Port Checker
Check whether TCP ports are open and reachable from the internet.
- Soon
SNMP OID Lookup
Translate common SNMP OIDs into names from a built-in MIB list.
Speed Test
Measure download and upload speed between your browser and NetKit.
Subnet Calculator
CIDR ranges, masks, broadcast and usable hosts for IPv4 and IPv6.
TCP/UDP Service Banner
Identify the service behind an open port from its greeting.
Traceroute
Follow every hop between our edge and your target.
Wake-on-LAN Packet Builder
Build the magic packet for a MAC address, ready to send from a script.
Bandwidth & Transfer Time
How long a file takes to move at a given speed, and the reverse.
Data Unit Converter
Convert between bits, bytes, KB, KiB, Mbps, MB/s and more.
- Soon
Fibre Optic Loss Budget
Will the link light up? Distance, connectors, splices and optics.
- Soon
IOPS & Storage Throughput
Turn disks and RAID level into realistic IOPS and MB/s.
Latency Budget
The fastest possible round trip between two places over fibre.
MTU & MSS
Work out MSS and payload size for tunnels, VPNs and PPPoE.
Storage / RAID Calculator
Usable capacity and fault tolerance for RAID 0, 1, 5, 6 and 10.
Supernet / Route Summariser
Collapse a list of routes into the smallest summary.
Throughput vs Latency
See the maximum TCP throughput for a window size and round-trip time.
VLAN Planner
Plan VLAN IDs and subnets for a site and export the layout.
Wildcard Mask Calculator
Convert between masks and wildcards and generate ACL lines.
Certificate Transparency Search
List every certificate ever issued for a domain.
CSP Builder
Build a Content-Security-Policy step by step and see how strong it is.
Encrypt / Decrypt (AES-GCM)
Encrypt and decrypt text with a passphrase, entirely in your browser.
Hash Generator
MD5, SHA-1, SHA-256 and SHA-512 hashes for text and files.
- Soon
Hash Identifier
Work out which algorithm produced a hash.
HTTP Headers
Inspect response headers and score security headers like CSP and HSTS.
Password Strength Analyzer
Estimate entropy and crack time, and check breach lists privately.
- Soon
Secret Scanner
Find leaked API keys, tokens and private keys in pasted text, in your browser.
security.txt Checker
Validate /.well-known/security.txt against RFC 9116.
- Soon
SRI Hash Generator
Create Subresource Integrity hashes for scripts and stylesheets.
SSL/TLS Checker
Inspect certificate chains, expiry, ciphers and protocol support.
- Soon
TLS Cipher Suite Reference
IANA, OpenSSL and GnuTLS names with how secure each suite is.
- Soon
Broken Link Checker
Crawl a site and list broken links and redirect chains.
- Soon
hreflang & Canonical Checker
Find language and canonical tag mistakes across pages.
- Soon
Meta Tag Generator
Write title, description, canonical, Open Graph and Twitter tags with length checks.
Open Graph / Social Preview
See how a link will look when shared on Slack, X, LinkedIn and Facebook.
- Soon
Readability Score
Grade a page or text for reading level, sentence length and jargon.
robots.txt & Sitemap
Validate robots.txt rules and sitemap files.
- Soon
Structured Data Validator
Check JSON-LD and schema.org markup.
- Soon
MOS / Call Quality Calculator
Estimate call quality from latency, jitter, packet loss and codec.
- Soon
Phone Number Validator
Check and format numbers in E.164, national and international styles.
- Soon
SIP URI Parser
Break a SIP or TEL URI into user, host, port and parameters.
- Soon
VoIP Bandwidth Calculator
Bandwidth per call by codec, including packet overheads.
Compression Checker
Check gzip and Brotli support and how much they save.
Cookie Inspector
List the cookies a page sets, with their flags, expiry and third parties.
CORS Tester
Send preflight requests and see exactly which origins are allowed.
HTTP/2 & HTTP/3 Support
See which HTTP versions and ALPN protocols a server supports.
Mixed Content Scanner
Find insecure http:// resources loaded on an HTTPS page.
Page Weight & Resources
List every resource a page loads and what it all weighs.
Redirect Tracer
Follow every redirect hop with its status code and headers.
Response Time (TTFB)
Break down DNS, connect, TLS and time to first byte.
- Soon
Tech Stack Detector
Identify a site's CMS, framework, CDN and analytics from its HTML and headers.
- Soon
Web App Manifest / PWA Checker
Validate the manifest, icons and installability.
Website Status
Check whether a site is up for everyone or just you.
- Soon
WebSocket Tester
Connect to a wss:// endpoint, send messages and see replies.
- Soon
MCC / MNC Lookup
Find the country and mobile network behind a mobile network code.
- Soon
RF Link Budget & Fresnel Zone
Will a point-to-point radio link work? Path loss, fade margin and clearance.
- Soon
Wi-Fi Channel Planner
Non-overlapping 2.4, 5 and 6 GHz channels, widths and realistic speeds.
Capabilities
Everything you need.
Nothing you don’t.
- 01
Private by design
No ads and no trackers. Tools run on your own server, and private keys are blocked in the browser before anything is sent.
- 02
Real DNS, from everywhere
Lookups go to public resolvers across five regions, so you see what the rest of the world sees, not just one cache.
- 03
Production-ready
Rate limits, input checks, signed-in admin access and plain-English errors, built in from day one.
- 04
Fast on every screen
Mobile-first layouts, instant search and keyboard shortcuts. It works the same on a phone as on a desktop.
How it works
Three steps.
Straight to the answer.
- 1❯ netkit tools --category dns
- 2CAA Records ready
- 3DNS Lookup ready
- 4DNS Propagation ready
- 5DNSSEC Validator soon
Coverage
Seen from
everywhere.
DNS changes don’t reach everyone at once. Propagation checks ask resolvers across the world at the same time, so you know when a change is really live.
- 25
- Public resolvers
- 5
- Regions
- 7
- Countries + global
- 7
Global
Cloudflare, Google, Quad9 +4
- 7
North America
Level3, Hurricane Electric, UltraDNS +4
- 4
Europe
DNS.WATCH, Freifunk München, SafeDNS +1
- 5
Asia
114DNS, AliDNS, DNSPod +2
- 2
South America
UOL, Claro
For developers
Automate it.
Same tools, one request.
Use the same tools from scripts, cron jobs and monitoring. One request, structured output.
- Consistent JSON responses for every tool
- API keys with per-key rate limits
- OpenAPI spec for generating clients
curl \ https://netkit.example.com/api/v1/dns \ -H "Authorization: Bearer $NETKIT_KEY" \ -d domain=example.com -d type=MX
{
"domain": "example.com",
"type": "MX",
"status": "ok",
"records": [
{
"priority": 10,
"host": "mail.example.com"
}
],
"resolver": "1.1.1.1",
"took_ms": 12
}