AltF Developers
Embed free tool widgets on your site
Any AltFTool tool that has a widget can run on your page inside an iframe: calculators, converters, generators and exam photo resizers. Pick the tool in the embed builder, choose a plain iframe, a responsive wrapper, a WordPress block or a paste-to-embed URL, preview it, and copy. Widgets are free, need no account and carry a small visible "Widget by AltFTool" credit.
- No API key
- Free, no sign-up
- Real responses, no mock data
- Code in 5 languages
Snippet types
- Iframe: works anywhere raw HTML is allowed - Ghost HTML cards, Webflow, Squarespace code blocks, hand-written pages.
- Responsive wrapper: the same iframe in a width-capped wrapper that grows taller below 640px, where widgets wrap to one column.
- WordPress block: paste into the block editor's Code editor view to get a Custom HTML block. No plugin is needed and none exists.
- Paste-to-embed URL: paste on its own line in an oEmbed-aware editor and it expands into the widget.
Rules for publishers
- Keep the "Widget by AltFTool" credit visible. It is a nofollow link, so it does not pass ranking signals.
- Do not wrap a widget in pages that claim it as your own product, and do not overlay ads on top of the iframe.
- You may shrink a widget; do not stretch it taller than its natural size, or it will show empty space.
Widget ids
A widget is addressed by its id, which is also its path: bmi-calculator is /embed/widget/bmi-calculator, transform/json-to-go is a converter, and exam-photo/ssc-cgl is an exam resizer. The /embed gallery searches all of them.
Limits, CORS and caching
| Endpoint | Returns | Browser CORS | Rate limit | Cache |
|---|---|---|---|---|
| GET /api/signals | Signals catalogue | Same origin only | 60 requests per minute per client | CDN 1 hour, then stale for up to 24 hours |
| GET /api/open-data/exam-photo-specs | Exam photo and signature specs | Any origin (Access-Control-Allow-Origin: *) | No per-client limit; served from cache | Browser and CDN 24 hours, stale for up to 7 days |
| GET /api/open-data/transform-converters | Format converter index | Any origin (Access-Control-Allow-Origin: *) | No per-client limit; served from cache | Browser and CDN 24 hours, stale for up to 7 days |
| GET /api/oembed | oEmbed provider | Any origin (Access-Control-Allow-Origin: *) | No per-client limit; cached at the CDN | CDN 1 hour, then stale for up to 24 hours; cache_age 86400 |
| GET /api/health | Site health | Same origin only | 30 requests per minute per client | CDN 60 seconds, then stale for up to 2 minutes |
Read from each route's source code on 2026-11-01.
Embed free tool widgets on your site: questions and answers
Do embedded widgets send my visitors' data to AltFTool?
The widget page loads from altftool.com like any iframe. Tools that run in the browser keep processing on the visitor's device; tools that need a server say so on their own page.
Can I remove the AltFTool credit?
No. The visible credit is the only condition of using the widgets for free.
Is there a WordPress plugin?
No, and none is needed. Use the WordPress block snippet or paste the tool URL.
More developer reference
- Free JSON API quickstart (no API key)Call AltFTool's free public JSON API in a minute: no key, no sign-up. Working cURL, JavaScript, Node.js, Python and PHP examples with caching and 429 handling.
- Signals API referenceGET /api/signals returns search-demand signals for tool ideas: query, category, search volume estimate, opportunity score and momentum. Parameters, fields and examples.
- Open data API referenceTwo free open datasets with CORS enabled: Indian exam photo and signature specs, and the AltFTool file converter index. Fields, attribution rules and code.
- oEmbed provider referenceAltFTool's oEmbed endpoint turns a pasted tool URL into a live widget in WordPress, Ghost and any oEmbed consumer. Parameters, response, errors and a live tester.
- Feeds, sitemaps and llms.txtEvery machine-readable AltFTool file: RSS feed, XML sitemap, Google News sitemap, llms.txt, llms-full.txt, ai.txt and robots.txt, with refresh times and uses.
- Rate limits, 429s and cachingAltFTool API rate limits and cache headers per endpoint, what a 429 response contains, and copyable retry-with-backoff code that honours Retry-After.
Free developer tools
Requests and APIs
JSON and data
Built something with it? Get it seen
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