generated: '2026-09-19'
method: probed
source: https://api.machinelibrary.ai/v1/pricing
name: Space Frontiers API Plans
sources:
- https://api.machinelibrary.ai/v1/pricing (machine-readable; identical at https://machinelibrary.ai/api/pricing and https://api.spacefrontiers.org/v1/pricing)
- https://machinelibrary.ai/pricing (pricing model text; per-endpoint table is rendered from the endpoint above)
- https://machinelibrary.ai/terms-of-service (3.2 formula, 4.2 arbitrary prepayment, 4.5-4.8 Pro subscription and refunds)
- openapi/machinelibrary-ai-openapi.yml createMppBalanceTopUp package enum + x-payment-info offers
- https://github.com/SpaceFrontiers/mcp README "Pricing"
checked: '2026-09-19'
summary: >-
  Pay-as-you-go from a prepaid USD balance with a published, machine-readable per-endpoint price list
  (base_price + multiplier x variable), plus a monthly "Pro" subscription whose price is not published and a
  feature-gated raw-download entitlement. No free tier is advertised beyond "Free credit already included for
  testing" (amount unstated); the MCP registry.json says free_tier false.
currency: USD
billing_model: prepaid balance, per-request deduction (Terms 3.3); Stripe cards (Visa, MasterCard, Amex) for humans, Stripe MPP / ACP for agents
prices_published: true
plan_count: 2
plans:
- name: Pay-as-you-go API access
  price: 0
  currency: USD
  billing_period: per request
  cta: Get API keys
  onboarding: self-serve (sign up with Google, GitHub or email; create a key at /keys; top up any amount at /payments)
  included_quota: unstated "free credit ... for testing"
  overage: n/a — every call is charged at the published rate
  rates:
  - endpoint: /v2/search
    endpoint_type: search
    base_price: 0.01
    multiplier: 0.001
    variable: requested results (limit)
    example: limit 10 = $0.02 per call
  - endpoint: /v2/conversations
    endpoint_type: conversation
    base_price: 0.05
    multiplier: 0.015
    variable: requested results (limit)
  - endpoint: /v2/documents/{id}
    endpoint_type: fetch
    base_price: 0.0
    multiplier: 7.32421875e-07
    variable: 4,096 returned tokens
    derived_note: multiplier x 4096 = $0.003 per 4,096 returned tokens (arithmetic on the published fields; the MCP README rounds a default fetch to $0.05)
  - endpoint: /v2/downloads/{id}.{format}
    endpoint_type: download
    base_price: 0.02
    multiplier: 0.0
    variable: document; book types are billed at 10x
    entitlement: requires the raw-document-downloads feature (403 without it)
  - endpoint: /v1/recognitions
    endpoint_type: ocr
    base_price: 0.01
    multiplier: 0.0
    variable: submitted document
    note: identical resubmissions are free
  mcp_rates_from_readme:
    search: $0.01 base + $0.001 per returned result
    fetch_document: $0.05
    search_in_document: $0.015
    referenced_by: adds a separately billed search
  limits: x-ratelimit-* headers (see rate-limits/); offset + limit <= 500 per search
- name: Pro
  price: null
  currency: USD
  billing_period: monthly, auto-renewing via Stripe
  cta: Manage subscription
  positioning: '"Pro subscription unlocks extra capabilities" (pricing page); "unlock additional features" (Terms 4.5)'
  included_quota: null
  overage: null
  cancellation: any time from Account Settings; remains active to period end; no partial refunds (Terms 4.6)
  price_change_notice: 30 days by email (Terms 4.7)
  note: Price and feature list are not published on any public page; the /profile page that manages it is behind sign-in.
prepaid_credit_packages:
  source: openapi createMppBalanceTopUp package enum; x-payment-info amounts are in cents
  packages: [usd-5, usd-10, usd-25, usd-50, usd-100, usd-250, usd-500, usd-1000]
  channels: [Stripe MPP top-up (POST /v2/payments/mpp/top-up), ACP checkout sessions (POST /v2/acp/checkout_sessions), A2A credit-top-up skill, MCP tool spacefrontiers_top_up_balance, human top-up at https://machinelibrary.ai/payments in an arbitrary amount (Terms 4.2)]
refunds: Unused balance is not refunded except where required by law (Terms 4.8); remaining balance is not refunded on termination (Terms 8.3).
rate_change_notice: 30 days (Terms 3.5)
bulk_data: Separate licensed product ("Premium datasets for purchase", https://machinelibrary.ai/datasets) scoped by source segment, use and volume; no published price; "There is no anonymous whole-corpus download."