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
24.2/100 emerging ▬ flat Agent 16/100 agent aware Full breakdown ↓
scored 2026-08-17 · rubric v0.11.0
AccessSelf serve
1 APIs 1 MCP Servers
CompanyPaymentsWeb3GamingFiat On-RampCryptocurrencyNFTMerchant of RecordDeveloper Tools

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-17 · rubric v0.11.0
Composite quality — 24.2/100 · emerging
Contract Quality 0.0 / 21
Developer Ergonomics 10.6 / 17
Commercial Clarity 2.2 / 17
Operational Transparency 0.6 / 11
Governance 0.3 / 10
Discoverability 6.5 / 9
Regulatory Posture 4.0 / 15
Agent readiness — 16/100 · agent aware
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
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
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Regulatory Posture applies to this provider. Its tags matched the Payments regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.
The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
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