Detect ArUco markers

POST /api/image-detect-aruco2 quota units per call · cache hits free

Detect ArUco fiducial markers in an image. Returns the marker ID, the four corners, and the rotation. Used in AR, robotics, and camera calibration.

Detects ArUco markers — printed black-and-white square fiducials with a unique ID encoded in the pattern. Common in AR / VR, robotics, and camera calibration. Returns each marker's ID, its four corners (image pixel coords), and a derived rotation angle. Multiple dictionaries are supported (4×4, 5×5, 6×6, 7×7).

Inputs

Name	Type	Default	Description
image*	file	—	Input image bytes.
dictionary	enum (4x4_50 \| 4x4_100 \| 4x4_250 \| 4x4_1000 \| 5x5_50 \| 5x5_100 \| 5x5_250 \| 5x5_1000 \| 6x6_50 \| 6x6_100 \| 6x6_250 \| 6x6_1000 \| 7x7_50 \| 7x7_100 \| 7x7_250 \| 7x7_1000)	"6x6_250"	ArUco dictionary.

Response

Modes: 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	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	`25 MiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`1 MiB`
Timeout	15s 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": "…" }