Photon is a feature of Jetpack, the WordPress plugin suite from Automattic. It serves your WordPress media files through a CDN and supports URL-parameter image transforms — resize, crop, filter. It's specifically for WordPress sites; there's no standalone API.
ChangeThisFile is a general-purpose file converter with an API. No WordPress dependency, no CMS required, no CDN serving — just file-in, file-out conversion across 690 routes.
These tools overlap only in the narrow case of image format conversion. Outside that, they serve very different use cases.
Quick verdict
For WordPress site image optimization: Photon (via Jetpack) is purpose-built and free for WordPress.com-connected sites.
For developers building non-WordPress apps or needing programmatic file conversion: ChangeThisFile. Free API, 690 routes, call /v1/convert directly with curl or any HTTP client.
For video, audio, documents, or ebooks: ChangeThisFile by default — Photon is image-only.
For the simplest API: ChangeThisFile. One POST with a file and a target format. No WordPress account, no Jetpack license.
Pricing comparison
Competitor pricing below is as of April 2026 - check the vendor's current pricing page before deciding.
| Plan | ChangeThisFile | Photon (Jetpack) |
|---|---|---|
| Free tier | 1,000 conversions/month (no card) | Free with Jetpack Free plan |
| Entry paid | $29/mo — 10,000 conversions | Bundled with Jetpack plans ($5–$50/mo) |
| Standalone access | Yes | No — requires Jetpack + WordPress |
| Non-WordPress use | Yes | No |
| Pricing model | Per conversion (flat count) | Included in Jetpack plan (no per-image billing) |
Photon's free access through Jetpack is genuinely good value for WordPress sites. But it requires WordPress.com connectivity, which means a Jetpack-connected WordPress installation. For developers outside WordPress, there's no way to access Photon directly.
Feature comparison
| Feature | ChangeThisFile | Photon |
|---|---|---|
| Free API tier | Yes — 1,000/mo, no card | Free via Jetpack (WordPress only) |
| SDK required | No — curl/fetch/requests directly | No (WordPress plugin) |
| Non-WordPress use | Yes | No |
| Image format conversion | Yes — JPG, PNG, WebP, HEIC, AVIF, GIF, etc. | Limited (JPEG/PNG output) |
| Resize / crop | No | Yes — URL params |
| CDN delivery | No | Yes — Automattic CDN |
| Video conversion | Yes | No |
| Document conversion | Yes | No |
| Client-side conversions | Yes — 161 routes | No |
What each tool covers
Photon handles WordPress media library images, serving them from Automattic's CDN with optional resize and crop via URL parameters. It primarily outputs JPEG and PNG — WebP output is available on some Jetpack plans. File type coverage is limited to what WordPress accepts as media uploads.
ChangeThisFile covers 690 specific conversion routes across 9 categories. Image formats include JPG, PNG, WebP, HEIC, AVIF, GIF, BMP, ICO, SVG, TIFF, and PSD. Beyond images: video (MP4, WebM, MKV, AVI, MOV), audio (MP3, WAV, FLAC, AAC), documents (PDF, DOCX, ODT, HTML, Markdown), data (CSV, JSON, YAML), spreadsheets (XLSX), fonts (TTF, OTF, WOFF), ebooks (EPUB, MOBI), and archives (ZIP, RAR, 7Z). No WordPress required.
API and developer experience
Photon isn't an API in the traditional sense — it's a WordPress/Jetpack feature that rewrites image URLs in your WordPress content to point at Automattic's CDN. URL transforms work by appending parameters to Photon CDN URLs. No direct API access outside WordPress.
ChangeThisFile API is a standard REST endpoint, no WordPress or CMS dependency. No SDK to install:
curl -X POST https://changethisfile.com/v1/convert \
-H "Authorization: Bearer ctf_sk_your_key" \
-F "file=@image.png" \
-F "target=webp" \
--output result.webp
Source format auto-detected from filename. Get a free key at changethisfile.com/v1/keys/free — no card required. Works from any language, any platform, any infrastructure.
When to choose which
| Use case | Recommended |
|---|---|
| WordPress site image CDN and optimization | Photon (Jetpack) |
| Non-WordPress web app or service | ChangeThisFile |
| Programmatic file conversion via API | ChangeThisFile |
| Convert video, audio, documents, or ebooks | ChangeThisFile |
| Free API tier without a CMS | ChangeThisFile |
| Resize/crop WordPress media images | Photon |
Photon is an excellent free tool if you're running WordPress with Jetpack — it's nearly zero configuration for image CDN benefits. But it's not a general-purpose API. For developers outside WordPress, or for any conversion beyond images, ChangeThisFile's free API tier is the right choice — 1,000 conversions/month, no card, no WordPress required.