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Build on AltFTool
AltF API & Widgets
Live API tester, copyable examples and developer utilities.
- Live API tester
- Copyable examples
- Developer utilities
Contacts a named public serviceOpen
For developers
Free AltFTool tools for developers
For developers, AltF API & Widgets documents AltFTool's public read APIs with a live tester, AltF DomainOps reads DNS, SPF, DMARC and RDAP records with the source shown, and AltF Security grades a site's security headers. AltF Flow runs ordered text and data transformations in the browser, and AltF Authenticator generates TOTP codes for testing two-factor sign-in.
Public read APIs, DNS and email records, security headers and local automation.
6 picks, in order
Best AltFTool products for developers
Ordered by how often this audience needs them. Every workspace is free and needs no account.
- Working
Domain health check and DNS toolkit
AltF DomainOps
A scored domain health report plus DNS lookup, resolver compare, live SSL check and RDAP expiry, with raw records shown.
- Health report
- DNS lookup and resolver compare
- SSL certificate and expiry check
- SPF, DMARC and DKIM
Contacts a named public serviceOpen - Working
Free private security check-up
AltF Security
Grade a website's security headers and check suspicious links.
- Password leak check
- Phishing link checker
- Website security headers
- Personal security checkup
Runs in your browserOpen - Public beta
Local workflow automation
AltF Flow
Chain text and data transformations with an execution log, all in the browser.
- Ordered actions
- Reusable recipes
- Execution log
Runs in your browserOpen - Working
TOTP 2FA code generator
AltF Authenticator
RFC-compatible TOTP codes for testing a two-factor sign-in flow.
- RFC 6238 TOTP and RFC 4226 HOTP
- QR and otpauth:// import
- Setup QR and secret generator
- Code verifier with clock drift
Runs in your browserOpen - Working
Internet speed test
AltF NetCheck
Ping, jitter and bufferbloat when you need to rule out the connection.
- Download and upload speed
- Ping, jitter and bufferbloat
- ISP, IP and server details
- Speed history and plan comparison
Contacts a named public serviceOpen
Go straight to a tool
Individual tools inside these workspaces
- API Testerfrom AltF API & Widgets
- API Documentation Makerfrom AltF API & Widgets
- API Stress Estimatorfrom AltF API & Widgets
- WHOIS Lookupfrom AltF DomainOps
- DNS Propagation Checkerfrom AltF DomainOps
- SPF, DKIM and DMARC Checkerfrom AltF DomainOps
- Password Strength Checkerfrom AltF Security
- Password Generatorfrom AltF Security
- Phishing URL X-Rayfrom AltF Security
- Bulk Text Replacerfrom AltF Flow
- JSON Editorfrom AltF Flow
- Cron Generatorfrom AltF Flow
- TOTP Code Generatorfrom AltF Authenticator
- 2FA Setup QR Generatorfrom AltF Authenticator
- Google Authenticator Export Decoderfrom AltF Authenticator
- Ping Testfrom AltF NetCheck
- WiFi Speed Testfrom AltF NetCheck
- Upload Speed Testfrom AltF NetCheck
FAQ
Questions from developers
Is there a rate limit on the AltFTool APIs?
Each endpoint documents its own behaviour on the AltF API & Widgets page; check there before building on one.
Does DomainOps store the domains I look up?
No. DNS lookups go from your browser to public resolvers; the report, registration and certificate checks pass through AltFTool's server and keep nothing.
Picks for other audiences
- For studentsStudy, cite, plan and stay safe online with free workspaces that need no account.AltF Campus · AltF Minutes · AltF CareerSee picks
- For creatorsRecord, caption, design thumbnails, research a channel and check your upload connection.AltF Creator · AltF NetCheck · AltF IdeaLabSee picks
- For job seekersPlan the search, write the application, prepare the interview and keep your accounts safe.AltF Career · AltF Security · AltF MinutesSee picks
- For small businessValidate ideas, check your domain and email setup, run tidy meetings and stay secure.AltF IdeaLab · AltF DomainOps · AltF MinutesSee picks
- For privacy firstWorkspaces that do their work on your device, so your input is not sent to a server.AltF Security · AltF Authenticator · AltF MinutesSee picks
More on AltFTool
Keep exploring AltFTool
- All free tools Every AltFTool utility in one searchable directory.
- AI tools directory Independent notes on AI tools, grouped by task.
- Free backlink sites Directories and communities where you can list a site or product.
- Browser extensions Extensions reviewed with plain store facts.
- AltF Labs Experiments and playful projects outside the product suite.
- Docs and guides How-to guides for AltFTool tools and SEO basics.
- Site map Every section of AltFTool on one page.