2s Convert API
The convert API from 2s — 2 operation(s) for convert.
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OpenAPI Specification
openapi: 3.2.0
info:
title: 2s — the (most) everything Convert API
version: '1'
summary: The (most) everything API.
description: 'The (most) everything API for AI agents: 575+ pay-per-call endpoints on one origin.'
contact:
name: 2s
url: https://2s.io
email: alley@2s.io
x-logo:
url: https://2s.io/icon-512.png
altText: 2s
x-guidance: 'Pay-per-call REST API for AI agents — hundreds of endpoints returning ground-truth data (US public records, company & legal identifiers, finance/SEC, crypto/web3, security & CVEs, medical codes, weather & geocoding, agriculture, energy, maritime, music, and more). Every endpoint is paid per call in USDC via x402 (Base or Solana) — no API key, no signup. Call any endpoint with no auth to get a 402 PaymentRequirements envelope, sign it (EIP-3009 on Base, partial SPL transfer on Solana), and retry with the PAYMENT-SIGNATURE header. Add ?trial=1 for one free real call per endpoint per hour to test before paying. To discover the right endpoint: GET https://2s.io/api/directory for the full catalog, or GET https://2s.io/api/search/endpoints?q=<natural-language task> for a ranked match. Per-call price is on each operation as x-payment-info (from $0.001). Batch up to 50 calls behind one payment via POST https://2s.io/api/batch/run.'
servers:
- url: https://2s.io
tags:
- name: Convert
paths:
/api/convert/currency:
get:
tags:
- Convert
summary: Convert an amount between currencies at a live or
description: Convert an amount between currencies at a live or historical exchange rate. Pass from + to (3-letter ISO 4217 codes) and optional amount (default 1) and date (YYYY-MM-DD for a historical rate; omit for the latest). Returns the converted result, the per-unit rate, and the effective rate date. Live data from the European Central Bank reference rates (via Frankfurter) — fetched per request, never stale; weekends/holidays use the last published business day. Coverage is the ECB major currencies. Distinct from fx.rates (the raw rate table) — this is the agent-friendly "X from = ? to" call.
operationId: convert_currency
deprecated: false
security:
- x402Payment: []
responses:
'200':
description: OK
content:
application/json:
schema:
type: object
required:
- data
- meta
properties:
data:
type: object
properties:
query:
type: object
properties:
from:
type: string
to:
type: string
amount:
type: number
date:
type: string
nullable: true
required:
- from
- to
- amount
- date
additionalProperties: false
rateDate:
type: string
rate:
type: number
result:
type: number
source:
$ref: '#/components/schemas/Source'
required:
- query
- rateDate
- rate
- result
- source
additionalProperties: false
meta:
$ref: '#/components/schemas/CallMeta'
'400':
$ref: '#/components/responses/BadRequest'
'402':
$ref: '#/components/responses/PaymentRequired'
'405':
$ref: '#/components/responses/MethodNotAllowed'
'500':
$ref: '#/components/responses/ServerError'
'502':
$ref: '#/components/responses/UpstreamError'
x-2s-id: convert.currency
x-2s-version: null
x-2s-price:
usd: 0.0036
x-2s-accepts:
- x402
x-2s-response-shape: legacy
x-payment-info:
price:
mode: fixed
currency: USD
amount: '0.003600'
protocols:
- x402: {}
parameters:
- name: from
in: query
required: true
description: Start of the range.
schema:
type: string
minLength: 3
maxLength: 3
- name: to
in: query
required: true
description: End of the range.
schema:
type: string
minLength: 3
maxLength: 3
- name: amount
in: query
required: false
description: Amount.
schema:
type: number
exclusiveMinimum: true
minimum: 0
- name: date
in: query
required: false
description: Date in YYYY-MM-DD format.
schema:
type: string
pattern: ^\d{4}-\d{2}-\d{2}$
- $ref: '#/components/parameters/TrialMode'
/api/convert/unit:
get:
tags:
- Convert
summary: 'Convert a value between units of measure: mass (g, kg, mg'
description: 'Convert a value between units of measure: mass (g, kg, mg, lb, oz, t, st), length (m, km, cm, mm, in, ft, yd, mi), volume (l, ml, m3, gal, gal-imp, qt, pt, cup, floz, tbsp, tsp), area (m2, km2, ft2, acre, ha), and temperature (C, F, K). Units are matched case-insensitively with common aliases (kg/kilogram/kgs). Returns {value, from, to, dimension, result}. Exact factors — the ground-truth answer a CPG/ETL pipeline needs instead of an LLM approximating conversions. Cross-dimension conversions (kg→m) return 400.'
operationId: convert_unit
deprecated: false
security:
- x402Payment: []
responses:
'200':
description: 'Normalized envelope: items = [conversion result]; total = 1.'
content:
application/json:
schema:
type: object
required:
- data
- meta
properties:
data:
type: object
properties:
ok:
type: boolean
enum:
- true
items:
type: array
items:
type: object
properties:
value:
type: number
from:
type: string
nullable: true
to:
type: string
nullable: true
dimension:
type: string
nullable: true
description: mass | length | volume | area | temperature
result:
type: number
nullable: true
reason:
type: string
nullable: true
required:
- value
- from
- to
- dimension
- result
- reason
additionalProperties: false
total:
type: integer
nullable: true
description: Total matching rows upstream; null when unknown.
source:
$ref: '#/components/schemas/Source'
required:
- ok
- items
- total
- source
additionalProperties: false
meta:
$ref: '#/components/schemas/CallMeta'
'400':
$ref: '#/components/responses/BadRequest'
'402':
$ref: '#/components/responses/PaymentRequired'
'405':
$ref: '#/components/responses/MethodNotAllowed'
'500':
$ref: '#/components/responses/ServerError'
'502':
$ref: '#/components/responses/UpstreamError'
x-2s-id: convert.unit
x-2s-version: null
x-2s-price:
usd: 0.0025
x-2s-accepts:
- x402
x-2s-response-shape: normalized
x-payment-info:
price:
mode: fixed
currency: USD
amount: '0.002500'
protocols:
- x402: {}
parameters:
- name: value
in: query
required: true
description: Value.
schema:
type: number
- name: from
in: query
required: true
description: Start of the range.
schema:
type: string
minLength: 1
maxLength: 40
- name: to
in: query
required: true
description: End of the range.
schema:
type: string
minLength: 1
maxLength: 40
- $ref: '#/components/parameters/TrialMode'
components:
schemas:
Source:
type: object
description: 'Provenance of the data: upstream provider, source URL, and license.'
properties:
provider:
type: string
description: Upstream data provider.
url:
type: string
description: Source URL or documentation link.
license:
type: string
description: License / usage terms for the data.
CallMeta:
type: object
description: Per-call meta envelope — endpoint id, cost, caller kind, settlement details.
X402PaymentRequiredV2:
type: object
description: x402 v2 PaymentRequired envelope. Pick any entry from accepts[], sign for that rail, retry with the PAYMENT-SIGNATURE header.
required:
- x402Version
- accepts
properties:
x402Version:
type: integer
const: 2
error:
type: string
description: Human-readable reason payment is required.
resource:
type: string
description: The resource URL being purchased.
accepts:
type: array
description: Payment requirement options, one per supported network (Base USDC, Solana USDC).
items:
type: object
required:
- scheme
- network
- amount
- asset
- payTo
- maxTimeoutSeconds
properties:
scheme:
type: string
enum:
- exact
network:
type: string
description: CAIP-2 network id, e.g. "eip155:8453" (Base) or "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp".
amount:
type: string
description: Price in atomic asset units (USDC has 6 decimals).
asset:
type: string
description: Asset contract address / mint.
payTo:
type: string
description: Treasury address to pay.
maxTimeoutSeconds:
type: integer
extra:
type: object
description: 'Rail-specific extras (EVM: EIP-712 domain name/version; Solana: feePayer).'
additionalProperties: true
extensions:
type: object
description: Optional discovery metadata (e.g. bazaar input/output schemas).
additionalProperties: true
responses:
PaymentRequired:
description: Payment required. Body contains the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients).
content:
application/json:
schema:
$ref: '#/components/schemas/X402PaymentRequiredV2'
UpstreamError:
description: Upstream provider error.
MethodNotAllowed:
description: Method not allowed — see `Allow` header for the supported method.
ServerError:
description: Internal server error.
BadRequest:
description: Bad request — invalid parameters.
parameters:
TrialMode:
name: trial
in: query
required: false
description: 'Try before you buy. Set to 1 for one free real call per endpoint per hour — no wallet or payment needed — to verify the endpoint before paying. Equivalent to sending the "X-2s-Trial: 1" request header. Works on every endpoint.'
schema:
type: integer
enum:
- 1
securitySchemes:
x402Payment:
type: apiKey
in: header
name: PAYMENT-SIGNATURE
description: 'x402 protocol v2: base64-encoded PaymentPayload. Call any paid endpoint without auth to receive a 402 with a multi-network PaymentRequirements envelope. Sign for either rail: EIP-3009 transferWithAuthorization (Base USDC) OR a partial SPL token transfer (Solana USDC). Retry with PAYMENT-SIGNATURE header. X-PAYMENT is also accepted for v1 buyer clients. See https://x402.org.'