GNU Taler

GNU Taler is an open‑source, privacy‑preserving electronic cash system developed as part of the GNU project. It enables merchants to accept digital payments that are fully auditable for tax purposes while preserving payer anonymity. The system is built on cryptographic protocols and integrates with GNU tools. Taler supports multiple currencies, provides a RESTful API for payment processing, and is maintained by the GNUnet e.V. and Taler Systems SA. The project aims to offer a free, secure, and tax‑compliant alternative to traditional payment methods.

GNU Taler is listed with 2 APIs on the APIs.io network. Tagged areas include Payments, E‑Cash, Open Source, Finance, and Privacy.

The GNU Taler catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

GNU Taler’s developer surface includes CLI, documentation, API reference, getting-started guide, support, engineering blog, and 16 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

27.2/100 thin Agent 16/100 agent aware Full breakdown ↓
scored 2026-10-31 · rubric v0.25.0 · Show this score on your site →

2 APIs

PaymentsE‑CashOpen Source Finance Privacy

Kin Score

Kin Score How this is scored →
scored 2026-10-31 · rubric v0.25.0

Composite quality — 27.2/100 · thin

Contract Quality 5.6 / 21

Developer Ergonomics 8.5 / 17

Access Clarity 0.0 / 17

Operational Transparency 1.2 / 11

Contract Governance 2.2 / 10

Discoverability 5.0 / 9

Regulatory Posture 3.6 / 15

Agent readiness — 16/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

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.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

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/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey)
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)

11 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 0.0 — up to +20.0 composite points
Contract Quality scores 26.3 — up to +18.4 composite points
Operational Transparency scores 10.5 — up to +11.6 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/gnu-taler/apis.yml: open an issue on github.com/api-evangelist/gnu-taler to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 2

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

GNU Taler Core APIs

Provides public and management REST APIs for Exchange, Merchant Backend, Wallet Core, Core Bank, and other components.

GNU Taler API

GNU Taler API as documented publicly: 176 operations. Contract generated from the documentation by API Evangelist (2026-10-28); not the provider's own document.

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Gnu Taler Context

120 classes · 209 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

GNU Taler API Rules

9 rules · 7 errors 1 warnings 1 info

SPECTRAL

JSON Schema 6

Standalone JSON Schema definitions for this provider's data models.

GetMonitorResponse

11 properties

JSON SCHEMA

PatchConversionRateClassesClassidRequest

10 properties

JSON SCHEMA

PatchConversionRateClassesResponse

13 properties

JSON SCHEMA

PostConversionRateClassesRequest

10 properties

JSON SCHEMA

PostConversionRateRequest

10 properties

JSON SCHEMA

PutDepositConfirmationRequest

16 properties

JSON SCHEMA

Security Posture 3

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

Gnu Taler Authentication

0 schemes

SECURITY

Gnu Taler Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Gnu Taler Vulnerability Disclosure

security.txt · contact published

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Gnu Taler Scopes

OAuth 2.0 · no documented scopes

0 scopes

SCOPES

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

WellKnown

WellKnown

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

Conformance

Build 3

SDKs, sample code, and the tooling you integrate with

CLI

CLI

SDKs

SDKs

Packages

Packages

Access & Security 5

Authentication, authorization, and security posture

Security

Security

SecurityTxt

SecurityTxt

SecurityTxt

SecurityTxt

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Company 3

The organization behind the API

Newsroom

Newsroom

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Hosts

Hosts

Source (apis.yml)

aid: gnu-taler
name: GNU Taler
description: GNU Taler is an open‑source, privacy‑preserving electronic cash system developed as part of the GNU project.
  It enables merchants to accept digital payments that are fully auditable for tax purposes while preserving payer anonymity.
  The system is built on cryptographic protocols and integrates with GNU tools. Taler supports multiple currencies, provides
  a RESTful API for payment processing, and is maintained by the GNUnet e.V. and Taler Systems SA. The project aims to offer
  a free, secure, and tax‑compliant alternative to traditional payment methods.
url: https://artifacts.apis.io/gnu-taler/apis.yml
image: https://www.taler.net/images/favicon.png
x-type: company
x-source: harvest:new-submission
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-28 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-28'
modified: '2026-10-28'
tags:
- Payments
- E‑Cash
- Open Source
- Finance
- Privacy
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Spectral
  url: rules/gnu-taler-rules.yml
- type: JSONLD
  url: json-ld/gnu-taler-context.jsonld
- type: Vocabulary
  url: vocabulary/gnu-taler-vocabulary.yml
- type: DataModel
  url: data-model/gnu-taler-data-model.yml
- type: CLI
  url: cli/gnu-taler-cli.yml
- type: Security
  url: security/gnu-taler-vulnerability-disclosure.yml
- type: Conformance
  url: conformance/gnu-taler-conformance.yml
- type: SecurityTxt
  url: well-known/gnu-taler-taler-security.txt
- type: SecurityTxt
  url: well-known/gnu-taler-security.txt
- type: WellKnown
  url: well-known/gnu-taler-well-known.yml
- type: Hosts
  url: hosts/gnu-taler-hosts.yml
- type: SDKs
  url: packages/gnu-taler-packages.yml
- type: Packages
  url: packages/gnu-taler-packages.yml
- type: Newsroom
  url: https://www.taler.net/en/news/index.html
- type: VulnerabilityDisclosure
  url: security/gnu-taler-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/gnu-taler-domain-security.yml
- type: Website
  url: https://www.taler.net/
- type: Documentation
  url: https://docs.taler.net/
- type: APIReference
  url: https://docs.taler.net/
- type: GettingStarted
  url: https://www.taler.net/en/docs.html
- type: Support
  url: mailto:support@taler.net
- type: Blog
  url: https://www.taler.net/en/news/
apis:
- name: GNU Taler Core APIs
  description: Provides public and management REST APIs for Exchange, Merchant Backend, Wallet Core, Core Bank, and other
    components.
  humanURL: https://docs.taler.net/core/api-overview.html
  aid: gnu-taler:gnu-taler-core-apis
- aid: gnu-taler:gnu-taler-api
  name: GNU Taler API
  description: 'GNU Taler API as documented publicly: 176 operations. Contract generated from the documentation by API Evangelist
    (2026-10-28);

    not the provider''s own document.'
  humanURL: https://docs.taler.net/core/api-apns.html
  baseURL: https://merchant-backend.demo.taler.net
  properties:
  - type: OpenAPI
    url: openapi/_ae-authored/gnu-taler-openapi-generated.yml
    x-provenance: generated
  - type: JSONSchema
    url: json-schema/gnu-taler-put-deposit-confirmation-request-schema.json
  - type: JSONSchema
    url: json-schema/gnu-taler-get-monitor-response-schema.json
  - type: JSONSchema
    url: json-schema/gnu-taler-post-conversion-rate-request-schema.json
  - type: JSONSchema
    url: json-schema/gnu-taler-patch-conversion-rate-classes-response-schema.json
  - type: JSONSchema
    url: json-schema/gnu-taler-patch-conversion-rate-classes-classid-request-schema.json
  - type: JSONSchema
    url: json-schema/gnu-taler-post-conversion-rate-classes-request-schema.json
x-coverage:
  state: unreadable
  reason: no-machine-readable-spec
  detail: Documentation provides API descriptions only as HTML pages, no OpenAPI or other machine‑readable contract.
  evidence:
  - url: https://docs.taler.net/core/api-overview.html
    status: 200
  checked: '2026-10-28'
x-submission-probe: 301 https://www.taler.net/, 2026-10-26
x-enrichment:
  date: '2026-10-28'
  status: enriched
  artifacts_added: 34
  pass: modular-v1
  engine: identity=oss,contract=oss,surfaces=oss,docs=oss,regulatory=oss

GNU Taler API — frequently asked questions

Does GNU Taler have an API?

Yes. APIs.io lists 2 APIs from GNU Taler, including GNU Taler Core APIs and GNU Taler API.

Is there an OpenAPI specification for the GNU Taler API?

Yes. APIs.io indexes 1 OpenAPI specification for GNU Taler, each linked for download from this page.

How do I authenticate with the GNU Taler API?

GNU Taler documents its authentication (0 schemes). The details are profiled on APIs.io as Gnu Taler Authentication.

Is the GNU Taler API ready for AI agents?

GNU Taler has a Kin Score of 27.2 out of 100 (thin) and an Agent Readiness score of 16.1 (agent-aware), scored by API Evangelist on 2026-10-31.

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