MP3 metadata

POST /api/mp3-metadata1 quota unit per call · cache hits free

Read MP3 metadata: title, artist, album, year, genre, track number, embedded artwork. Supports both ID3v1 and ID3v2 tags.

Reads the ID3 tags from an MP3 file and returns the metadata as JSON: title, artist, album, album artist, year, genre, track number, comment, composer, plus a flag indicating whether embedded cover-art is present. Both ID3v1 (the simpler trailer at the end of the file) and ID3v2 (richer header at the start) are supported. When both are present, ID3v2 wins. Audio characteristics are also reported: duration, bitrate, sample rate, channels, and the codec profile.

Inputs

Name	Type	Default	Description
mp3*	file	—	MP3 file bytes.

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	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	`100 MiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`256 KiB`
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": "…" }

Code samples

Built from the tagged example.

# Download or substitute the example input:
#   curl -O https://xtract.bot/examples/mp3-fixtures/sample.mp3
MP3=$(base64 -w0 < sample.mp3)

curl -X POST https://api.xtract.bot/api/mp3-metadata \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -H "X-Account-Id: $XTRACT_ACCOUNT_ID" \
  -H "X-Api-Key: $XTRACT_API_KEY" \
  -d '{
  "mp3": "__BASE64_MP3__"
}'