String Technology Inc

String (string.xyz) is a fiat interoperability platform for Web3 gaming, operated by String Technology Inc and backed by 500 Global. String lets game developers accept credit-card and bank payments natively inside their games, acting as the merchant of record and counterparty for fiat on/off ramps, NFT purchases, and cross-chain payments. A player pays fiat on traditional rails and String delivers the digital asset on-chain — either by interacting with the game's smart contract to mint/send an NFT or by sending a token from its treasury to the player's wallet. String ships three integration surfaces — String Checkout (drop-in payment app), a Unity SDK, and String Direct (custom web SDK) — all wrapping a REST API at string-api.xyz that covers API keys, contracts, platforms (games), members, organizations, users (players), saved cards, wallet-signature login, quotes, and transactions.

String Technology Inc publishes 1 API on the APIs.io network. Tagged areas include Company, Payments, Web3, Gaming, and Fiat On-Ramp.

String Technology Inc’s developer surface includes documentation, API reference, getting-started guide, signup flow, sandbox, authentication, and 15 more developer resources.

🌐 Visit website 📡 Source on GitHub
28.8/100 emerging ▬ flat Agent 34/100 agent aware Full breakdown ↓
scored 2026-07-27 · rubric v0.5
AccessSelf serve
1 APIs 1 MCP Servers
CompanyPaymentsWeb3GamingFiat On-RampCryptocurrencyNFTMerchant of RecordDeveloper Tools

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 28.8/100 · emerging
Contract Quality 0.0 / 25
Developer Ergonomics 14.8 / 20
Commercial Clarity 2.6 / 20
Operational Transparency 0.7 / 13
Governance 0.0 / 12
Discoverability 9.3 / 10
Agent readiness — 34/100 · agent aware
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
MCP Server 12 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 0 / 7
Typed Event Surface 0 / 6
Agent Skills 5 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/string-technology-inc: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

String API

REST API for String's fiat-for-Web3-gaming platform — quotes and transactions (fiat on/off ramp, NFT purchase, cross-chain), plus management of API keys, contracts, platforms (g...

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

string-technology-inc-mcp.yml

MCP SERVER

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

String Technology Inc Authentication

apiKey/walletSignature/session · 4 schemes

SECURITY

String Technology Inc Domain Security

TLSv1.3 · HSTS

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted
 SignUp
SignUp
 Sandbox
Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt
LLMsTxt
 MCPServer
MCPServer
 AgentSkill
AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Components
Components
 ErrorCatalog
ErrorCatalog
 Conventions
Conventions
 Conformance
Conformance
 Lifecycle
Lifecycle
 DataModel
DataModel

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 Packages
Packages
 SDKs
SDKs

Access & Security 2

Authentication, authorization, and security posture

Authentication
Authentication
 DomainSecurity
DomainSecurity

Company 1

The organization behind the API

Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: string-technology-inc
name: String Technology Inc
description: String (string.xyz) is a fiat interoperability platform for Web3 gaming, operated by String Technology Inc and
  backed by 500 Global. String lets game developers accept credit-card and bank payments natively inside their games, acting
  as the merchant of record and counterparty for fiat on/off ramps, NFT purchases, and cross-chain payments. A player pays
  fiat on traditional rails and String delivers the digital asset on-chain — either by interacting with the game's smart contract
  to mint/send an NFT or by sending a token from its treasury to the player's wallet. String ships three integration surfaces
  — String Checkout (drop-in payment app), a Unity SDK, and String Direct (custom web SDK) — all wrapping a REST API at string-api.xyz
  that covers API keys, contracts, platforms (games), members, organizations, users (players), saved cards, wallet-signature
  login, quotes, and transactions.
url: https://raw.githubusercontent.com/api-evangelist/string-technology-inc/refs/heads/main/apis.yml
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://avatars.githubusercontent.com/u/104804397?v=4
x-type: company
x-source: vc-portfolio
x-backed-by:
- 500-global
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-21'
tags:
- Company
- Payments
- Web3
- Gaming
- Fiat On-Ramp
- Cryptocurrency
- NFT
- Merchant of Record
- Developer Tools
apis:
- name: String API
  description: REST API for String's fiat-for-Web3-gaming platform — quotes and transactions (fiat on/off ramp, NFT purchase,
    cross-chain), plus management of API keys, contracts, platforms (games), members, organizations, users (players), saved
    cards, and wallet-signature authentication.
  humanURL: https://docs.string.xyz
  baseURL: https://string-api.xyz
  tags:
  - Payments
  - Web3
  - Gaming
  properties:
  - type: Documentation
    url: https://docs.string.xyz
  - type: APIReference
    url: https://docs.string.xyz/reference/get_apikeys
  - type: GettingStarted
    url: https://docs.string.xyz/docs/getting-started
  - type: LLMsTxt
    url: llms/string-technology-inc-llms.txt
  - type: Authentication
    url: authentication/string-technology-inc-authentication.yml
  - type: ErrorCatalog
    url: errors/string-technology-inc-problem-types.yml
  - type: Conventions
    url: conventions/string-technology-inc-conventions.yml
  - type: Conformance
    url: conformance/string-technology-inc-conformance.yml
  - type: Lifecycle
    url: lifecycle/string-technology-inc-lifecycle.yml
  - type: DataModel
    url: data-model/string-technology-inc-data-model.yml
  - type: MCPServer
    url: mcp/string-technology-inc-mcp.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://string.xyz
- type: DeveloperPortal
  url: https://docs.string.xyz
- type: Documentation
  url: https://docs.string.xyz
- type: APIReference
  url: https://docs.string.xyz/reference/get_apikeys
- type: GettingStarted
  url: https://docs.string.xyz/docs/getting-started
- type: GitHubOrganization
  url: https://github.com/String-xyz
- type: SignUp
  url: https://sandbox.string.xyz/login
- type: Sandbox
  url: sandbox/string-technology-inc-sandbox.yml
- type: LLMsTxt
  url: llms/string-technology-inc-llms.txt
- type: Packages
  url: packages/string-technology-inc-packages.yml
- type: SDKs
  url: packages/string-technology-inc-packages.yml
- type: Components
  url: components/string-technology-inc-components.yml
- type: Authentication
  url: authentication/string-technology-inc-authentication.yml
- type: ErrorCatalog
  url: errors/string-technology-inc-problem-types.yml
- type: Conventions
  url: conventions/string-technology-inc-conventions.yml
- type: Conformance
  url: conformance/string-technology-inc-conformance.yml
- type: Lifecycle
  url: lifecycle/string-technology-inc-lifecycle.yml
- type: DataModel
  url: data-model/string-technology-inc-data-model.yml
- type: MCPServer
  url: mcp/string-technology-inc-mcp.yml
- type: DomainSecurity
  url: security/string-technology-inc-domain-security.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 15
  pass: local-v1