PNG to ICO

POST /api/image-png-to-ico1 quota unit per call · cache hits free

Convert PNG to ICO online or via API. Produces a multi-size Windows icon / favicon with Vista-style PNG-compressed entries — pick your own size list (16, 32, 48, up to 256).

Builds a Windows ICO from a PNG. Each requested size becomes a PNG-compressed directory entry (the Vista-style layout every modern browser and Windows version reads), downscaled with an alpha-weighted box filter. - `sizes` is a comma-separated list, e.g. "16,32,48" (the default) or "16,32,48,256". Up to 10 sizes, each ≤ 256 px. - The source must be at least as large as the biggest requested size — icons are never upscaled. The symmetric pair of image-ico-to-png. For a complete favicon bundle (PNG set + manifest), see favicon-generate.

Inputs

Name	Type	Default	Description
image*	file	—	Input PNG image (at least as large as the biggest requested size).
sizes	string	"16,32,48"	Comma-separated icon sizes in pixels, each 1-256. At most 10 sizes.

Response

Modes: binary, json. Cache: yes (24h TTL).

Every response carries x-cache (HIT / MISS / BYPASS), x-cache-signature (stable across identical inputs), and the rate-limit headers listed below.

Quota & limits

Cost per call	1 unit against the 10,000-unit monthly quota. Cache hits are free — only cache misses decrement.
Burst limit	200 requests per rolling minute, shared across all tools.
Max request size	`16 MiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`8 MiB`
Timeout	30s wall clock.
Rate-limit headers	`X-RateLimit-Limit`, `X-RateLimit-Remaining`, `X-RateLimit-Burst-Limit` on every response; `X-Quota-Warning` once 80% of the monthly quota is spent; `Retry-After` on 429s.

Errors

Errors are JSON with an error string; schema failures add a details object (Zod's flattened field errors).

Status	When	Body
400	Input fails the tool's schema (wrong type, missing required field, malformed base64) or the file bytes can't be parsed as the expected format.	{ "error": "invalid inputs", "details": { "fieldErrors": { … } } }
401	Missing or invalid X-Api-Key / X-Account-Id headers (or no session when called from the browser).	{ "error": "unauthorized" }
404	Unknown tool id, or calling /api/* on the website hostname instead of api.xtract.bot.	{ "error": "not found" }
413	Request body over the tool's max request size, or an image header declaring more megapixels than the tool's pixel budget.	{ "error": "…exceeds maxRequestBytes…" }
415	Content-Type isn't application/json on the json-body transport.	{ "error": "unsupported content-type; expected application/json" }
429	Monthly quota or the 200/min burst limit exhausted. Check Retry-After and the X-RateLimit-* headers.	{ "error": "monthly quota exceeded", "monthRemaining": 0, … }
5xx	Conversion engine failure. Safe to retry; if it persists, the input is hitting a bug — please report it.	{ "error": "…" }

Code samples

Built from the favicon-trio example.

# Download or substitute the example input:
#   curl -O https://xtract.bot/examples/image-png-to-ico/sample.png
IMAGE=$(base64 -w0 < sample.png)

curl -X POST https://api.xtract.bot/api/image-png-to-ico \
  -H "Content-Type: application/json" \
  -H "Accept: application/octet-stream" \
  -H "X-Account-Id: $XTRACT_ACCOUNT_ID" \
  -H "X-Api-Key: $XTRACT_API_KEY" \
  -d '{
  "image": "'"$IMAGE"'"
}'