Free PNG placeholder API — real PNG bytes at a URL, no signup

Most free placeholder services default to SVG — and SVG is the right default for the web: crisp at any size, tiny, cheap to render. But a placeholder that only exists as SVG is useless in a surprising number of places: HTML email (Gmail and most clients won't render SVG in <img>), og:image social cards (crawlers want raster — see the dedicated OG image API guide), React Native's <Image> and Flutter's Image.network (no SVG without an extra package), native iOS/Android image views, and any test pipeline that actually decodes the image (Pillow, sharp, OpenCV — none of them open SVG out of the box).

Mockbird serves placeholders as real PNG bytes — 8-bit RGBA, standard non-interlaced PNG, decodes anywhere PNG does. No signup, no key, CORS on, and deterministic: the same URL always returns byte-identical output, so image-diff tests don't flake.

The 10-second version

# a 300x200 PNG placeholder — this URL works right now
curl -o p.png https://mockbird.mockbird.workers.dev/m/demo/img/300x200.png

# custom text + colors, 640x360, via ?format=png
curl -o hero.png "https://mockbird.mockbird.workers.dev/m/demo/img/640x360?format=png&text=Hero&bg=1e293b&fg=f8fafc"

# avatars too — 128x128 PNG initials for "Ada Lovelace"
curl -o ada.png "https://mockbird.mockbird.workers.dev/m/demo/avatar/128.png?name=Ada+Lovelace"

Prefer clicking to typing? The live playground builds any of these URLs interactively with an instant preview.

Three ways to ask for PNG

Without any of these, /img returns SVG — the better choice wherever SVG renders.

Every parameter works in PNG

The PNG renderer is a raster twin of the SVG one — same layout, same colors, same determinism. All of these compose:

Avatars have the same twin: /avatar/128.png?name=Ada+Lovelace works in all three styles (initials, identicon, shapes) with the same params as the SVG avatar API, and the initials style is ui-avatars-compatible.

Where PNG (not SVG) is the requirement

• HTML email. Gmail, Outlook and most clients don't render SVG in <img> tags. Seeding a mock newsletter or testing an email template? Point the images at .png URLs and they render in the real inbox preview.
• og:image / social cards. Facebook, Twitter/X, Slack and Discord crawlers expect raster images for link previews. An SVG og:image simply doesn't show.
• Native mobile. React Native's <Image source={{uri}}>, Flutter's Image.network(), iOS UIImage, Android BitmapFactory — none decode SVG without an extra dependency. PNG placeholder URLs work in all of them unchanged.
• Pipelines that decode images. Pillow, sharp, OpenCV, image-diff test tools — they open PNG, not SVG. If your test asserts on pixels or dimensions, you need raster; deterministic output means the assertion holds run after run.
• Anything that caches by content hash. Byte-identical output per URL means your CDN, snapshot tests and lockfile-style image manifests stay stable.

Limits — stated plainly

• PNG output is capped at 1,000,000 pixels (e.g. 1000×1000). Over the cap you get an explanatory 400, not a truncated image. SVG has no such cap (up to 2000 px per side) — use SVG for larger sizes.
• ?blur on PNG is capped at 512×512 (blur is the expensive raster op; LQIP images are tiny anyway). SVG blurs at any size.
• Text renders in a deliberately blocky bitmap font — fine for "this is a placeholder", not for typography demos. The SVG output's text is crisper.
• Output is PNG only. The .jpg suffix is accepted but serves PNG bytes — if you need actual JPEG/WebP/AVIF encoding (smaller files for photo-like content), placehold.co does that and we don't.

Honest comparison

Written by the Mockbird maker — bias disclosed. Where the others genuinely win: placehold.co encodes real JPEG/WebP/AVIF, retina variants and custom fonts; picsum.photos serves real photographs, which look far better in any read-only grid. Use them there. Use Mockbird when the placeholder should live at the same base URL as the rest of your fake backend — one host to swap when the real backend lands — or when you specifically need deterministic PNG bytes next to mock JSON. Uptime of all of them is tracked live here.

The actual point: mock data whose image URLs decode anywhere

The placeholder endpoint exists because mock records need images that render in whatever consumes them. Create a seeded e-commerce backend and every product can carry a PNG URL that works in an email template, a React Native screen, and a Pillow-based test alike:

curl -X POST https://mockbird.mockbird.workers.dev/api/projects \
  -H 'content-type: application/json' \
  -d '{"preset":"ecommerce"}'
# → live REST API with products/orders/customers/reviews
#   image fields: https://mockbird.mockbird.workers.dev/m/<id>/img/640x480?seed=…
#   (SVG by default — append .png before the ? wherever raster is required)

Full parameter reference in the docs. More guides: free placeholder image API · picsum alternative · avatar placeholder API · identicon API · testing loading & error states. Create your API →