Ed25519 sign

POST /api/ed25519-sign1 quota unit per call · cache hits free

Sign arbitrary data with an Ed25519 private key (PKCS#8 PEM). Returns a 64-byte signature in hex / base64 / base64url. Deterministic, no parameter tuning required.

Signs `data` with an Ed25519 private key (PKCS#8 PEM). Output is the 64-byte Ed25519 signature in your chosen encoding. Ed25519 signatures are deterministic (no nonce surprise), 64 bytes regardless of message size, and resistant to side-channel and curve-twist attacks by construction.

Inputs

Name	Type	Default	Description
data*	string	—	Message to sign.
dataFormat	enum (text \| hex \| base64)	"text"	Encoding of `data`.
privateKeyPem*	string	—	Ed25519 private key in PKCS#8 PEM format.
outputFormat	enum (hex \| base64 \| base64url)	"base64"	Encoding of the signature.

Response

Modes: json. Cache: not cacheable.

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	`4 MiB` (base64 inflates file payloads ~33% — the limit applies to the decoded bytes).
Max response size	`8 KiB`
Timeout	10s 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 sign-text example.


curl -X POST https://api.xtract.bot/api/ed25519-sign \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -H "X-Account-Id: $XTRACT_ACCOUNT_ID" \
  -H "X-Api-Key: $XTRACT_API_KEY" \
  -d '{
  "data": "the eagle has landed",
  "privateKeyPem": "-----BEGIN PRIVATE KEY-----\nMC4CAQAwBQYDK2VwBCIEIKPg3RCUW1hziGofXv60GgitNzmEU0cwo7toUnvr6m5a\n-----END PRIVATE KEY-----"
}'