Sequence website screenshot

Sequence

Sequence is a web3 developer platform (0xsequence, now part of Polygon Labs) for building blockchain applications: smart-contract wallets, a universal crypto payments and swap layer, a real-time multi-chain Indexer with balances, token prices, contract events and webhooks, plus Metadata, Marketplace, Transactions (Relayer) and Analytics APIs. Its backend APIs are webrpc-generated (POST /rpc/{Service}/{Method}) authenticated with a project access key and secret JWT, and it ships first-party SDKs for TypeScript, Go, Unity, Unreal, Kotlin and Swift plus a CLI. Backed by a16z and Polychain.

Sequence publishes 5 APIs on the APIs.io network, including Analytics API, Marketplace API, public API, and 2 more. Tagged areas include Company, Web3, Blockchain, Wallets, and Payments.

The Sequence catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Sequence’s developer surface includes documentation, API reference, signup flow, support, engineering blog, pricing, changelog, and 23 more developer resources.

🌐 Visit website 📡 Source on GitHub
42.4/100 developing ▬ flat Agent 33/100 agent aware Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0
AccessSelf serve
5 APIs 1 MCP Servers
CompanyWeb3BlockchainWalletsPaymentsCryptoIndexerNFTDeveloper PlatformGaming

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0
Composite quality — 42.4/100 · developing
Contract Quality 11.7 / 21
Developer Ergonomics 10.0 / 17
Access Clarity 1.8 / 17
Operational Transparency 4.7 / 11
Contract Governance 1.7 / 10
Discoverability 6.9 / 9
Regulatory Posture 4.0 / 15
Agent readiness — 33/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 0 / 10
Documented Reversibility 0 / 6
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 7 / 7
Rate-Limit Signaling 0 / 7
Typed Event Surface 6 / 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/sequence: 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 5

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

Sequence Analytics API

The Analytics API from Sequence — 177 operation(s) for analytics.

Sequence Marketplace API

The Marketplace API from Sequence — 34 operation(s) for marketplace.

Sequence public API

Endpoints accessible by passing your project-access-key in the header. This is injected whenever you login automatically.

Sequence Rpc API

The Rpc API from Sequence — 32 operation(s) for rpc.

Sequence secret API

Endpoints that require a Sequence service token intended to be secret. You can manually generate one on Sequence Builder and pass it as a Bearer Token.

Open Collections 6

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Api Analytics API

OPEN COLLECTION

Api Analytics Marketplace API

OPEN COLLECTION

Api Analytics public API

OPEN COLLECTION

Api Analytics Rpc API

OPEN COLLECTION

Api Analytics secret API

OPEN COLLECTION

MCP Servers 1

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

Sequence MCP Server

MCP SERVER

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Sequence Indexer Webhooks

ASYNCAPI

Security Posture 2

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

Sequence Authentication

apiKey/http · 2 schemes

SECURITY

Sequence Domain Security

TLSv1.3 · DMARC

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 SignUp
SignUp
 Sandbox
Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt
LLMsTxt
 MCPServer
MCPServer
 WellKnown
WellKnown
 AgentSkill
AgentSkill

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

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

Scroll for all 7

Build 4

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 Packages
Packages
 SDKs
SDKs
 CLI
CLI

Access & Security 2

Authentication, authorization, and security posture

Authentication
Authentication
 DomainSecurity
DomainSecurity

Operate 4

Status, limits, changes, and where to get help

Support
Support
 HelpCenter
HelpCenter
 StatusPage
StatusPage
 ChangeLog
ChangeLog

Commercial 1

Pricing, plans, and the legal terms of use

Pricing
Pricing

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

Overlay
Overlay

Source (apis.yml)

apis.yml Raw ↑ 
aid: sequence
name: Sequence
description: 'Sequence is a web3 developer platform (0xsequence, now part of Polygon Labs) for building blockchain applications:
  smart-contract wallets, a universal crypto payments and swap layer, a real-time multi-chain Indexer with balances, token
  prices, contract events and webhooks, plus Metadata, Marketplace, Transactions (Relayer) and Analytics APIs. Its backend
  APIs are webrpc-generated (POST /rpc/{Service}/{Method}) authenticated with a project access key and secret JWT, and it
  ships first-party SDKs for TypeScript, Go, Unity, Unreal, Kotlin and Swift plus a CLI. Backed by a16z and Polychain.'
url: https://raw.githubusercontent.com/api-evangelist/sequence/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- a16z
- polychain
x-tier: stub
x-tier-reason: portfolio-lead
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://sequence.xyz/favicon.ico
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
tags:
- Company
- Web3
- Blockchain
- Wallets
- Payments
- Crypto
- Indexer
- NFT
- Developer Platform
- Gaming
apis:
- aid: sequence:sequence-analytics-api
  name: Sequence Analytics API
  description: The Analytics API from Sequence — 177 operation(s) for analytics.
  humanURL: https://docs.sequence.xyz/api-references/indexer/overview
  baseURL: https://mainnet-indexer.sequence.app
  tags:
  - Analytics
  properties:
  - type: OpenAPI
    url: openapi/sequence-analytics-api-openapi.yml
  - type: Webhooks
    url: asyncapi/sequence-indexer-webhooks.yml
- aid: sequence:sequence-marketplace-api
  name: Sequence Marketplace API
  description: The Marketplace API from Sequence — 34 operation(s) for marketplace.
  humanURL: https://docs.sequence.xyz/api-references/indexer/overview
  baseURL: https://mainnet-indexer.sequence.app
  tags:
  - Marketplace
  properties:
  - type: OpenAPI
    url: openapi/sequence-marketplace-api-openapi.yml
  - type: Webhooks
    url: asyncapi/sequence-indexer-webhooks.yml
- aid: sequence:sequence-public-api
  name: Sequence public API
  description: Endpoints accessible by passing your project-access-key in the header. This is injected whenever you login
    automatically.
  humanURL: https://docs.sequence.xyz/api-references/indexer/overview
  baseURL: https://mainnet-indexer.sequence.app
  tags:
  - Public
  tags_raw:
  - public
  properties:
  - type: OpenAPI
    url: openapi/sequence-public-api-openapi.yml
  - type: Webhooks
    url: asyncapi/sequence-indexer-webhooks.yml
- aid: sequence:sequence-rpc-api
  name: Sequence Rpc API
  description: The Rpc API from Sequence — 32 operation(s) for rpc.
  humanURL: https://docs.sequence.xyz/api-references/indexer/overview
  baseURL: https://mainnet-indexer.sequence.app
  tags:
  - RPC
  tags_raw:
  - Rpc
  properties:
  - type: OpenAPI
    url: openapi/sequence-rpc-api-openapi.yml
  - type: Webhooks
    url: asyncapi/sequence-indexer-webhooks.yml
- aid: sequence:sequence-secret-api
  name: Sequence secret API
  description: Endpoints that require a Sequence service token intended to be secret. You can manually generate one on Sequence
    Builder and pass it as a Bearer Token.
  humanURL: https://docs.sequence.xyz/api-references/indexer/overview
  baseURL: https://mainnet-indexer.sequence.app
  tags:
  - Secret
  tags_raw:
  - secret
  properties:
  - type: OpenAPI
    url: openapi/sequence-secret-api-openapi.yml
  - type: Webhooks
    url: asyncapi/sequence-indexer-webhooks.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Overlay
  url: overlays/sequence-analytics-overlay.yaml
- type: Website
  url: https://sequence.xyz
- type: DeveloperPortal
  url: https://sequence.build
- type: Documentation
  url: https://docs.sequence.xyz
- type: APIReference
  url: https://docs.sequence.xyz/api-references/overview
- type: SignUp
  url: https://sequence.build
- type: Support
  url: https://support.sequence.xyz/en/
- type: HelpCenter
  url: https://support.sequence.xyz/en/
- type: Blog
  url: https://sequence.xyz/blog
- type: GitHubOrganization
  url: https://github.com/0xsequence
- type: Pricing
  url: https://sequence.xyz/pricing
- type: StatusPage
  url: lifecycle/sequence-lifecycle.yml
- type: ChangeLog
  url: changelog/sequence-changelog.yml
- type: Packages
  url: packages/sequence-packages.yml
- type: SDKs
  url: packages/sequence-packages.yml
- type: CLI
  url: cli/sequence-cli.yml
- type: Components
  url: components/sequence-components.yml
- type: LLMsTxt
  url: llms/sequence-llms.txt
- type: MCPServer
  url: mcp/sequence-mcp.yml
- type: WellKnown
  url: well-known/sequence-well-known.yml
- type: Authentication
  url: authentication/sequence-authentication.yml
- type: DomainSecurity
  url: security/sequence-domain-security.yml
- type: Conventions
  url: conventions/sequence-conventions.yml
- type: ErrorCatalog
  url: errors/sequence-problem-types.yml
- type: Conformance
  url: conformance/sequence-conformance.yml
- type: Lifecycle
  url: lifecycle/sequence-lifecycle.yml
- type: DataModel
  url: data-model/sequence-data-model.yml
- type: Sandbox
  url: sandbox/sequence-sandbox.yml
- type: Webhooks
  url: asyncapi/sequence-indexer-webhooks.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 30
  pass: local-v1