Image resize

POST /api/image-resize2 quota units per call · cache hits free

Resize an image to a target width and height. Accepts PNG, JPEG, WebP, BMP, GIF, PNM, PCX and QOI; outputs those plus ICO and TGA. Pass only one dimension to preserve aspect ratio. High-quality Lanczos resampling.

Resizes the input to the requested `width` × `height` in pixels. Pass `width=0` (or omit) to derive width from height, and vice versa, preserving the source aspect ratio. At least one of `width` and `height` must be > 0. Resampling uses Lanczos — high-quality. Output format defaults to the input's format; override with `format` to re-encode at a different format in the same call. Accepted inputs: PNG, JPEG, WebP, BMP, GIF, PNM (PBM/PGM/PPM), PCX, QOI. Outputs additionally include ICO and TGA (encode-only — the engine cannot decode those two). Animated GIF input is flattened to its first frame.

Inputs

Name	Type	Default	Description
image*	file	—	Input image (PNG / JPEG / WebP / BMP / GIF / PNM / PCX / QOI).
width	number (0…16384)	0	Target width in pixels. 0 (default) means derive from height to preserve aspect ratio.
height	number (0…16384)	0	Target height in pixels. 0 (default) means derive from width to preserve aspect ratio.
format	enum (png \| jpeg \| webp \| bmp \| ico \| gif \| tga \| pnm \| pcx \| qoi)	—	Output format. Defaults to the input's format. ICO and TGA are encode-only (not accepted as input).

Response

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

Large outputs stream: responses over the 4 MiB cache limit are piped through as they are produced instead of buffered. They carry x-cache-skip: size and are never cached — identical follow-up calls recompute.

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	2 units 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	`48 MiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`32 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 resize-jpeg-half example.

# Download or substitute the example input:
#   curl -O https://xtract.bot/examples/image-resize-jpeg/pool-ducks.jpg
IMAGE=$(base64 -w0 < pool-ducks.jpg)

curl -X POST https://api.xtract.bot/api/image-resize \
  -H "Content-Type: application/json" \
  -H "Accept: application/octet-stream" \
  -H "X-Account-Id: $XTRACT_ACCOUNT_ID" \
  -H "X-Api-Key: $XTRACT_API_KEY" \
  -d '{
  "width": 16,
  "height": 0,
  "image": "'"$IMAGE"'"
}'