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 22 more developer resources.

🌐 Visit website 📡 Source on GitHub
48.0/100 developing ▬ flat Agent 61/100 agent native Full breakdown ↓
scored 2026-07-27 · rubric v0.5
AccessSelf serve
5 APIs 1 MCP Servers
CompanyWeb3BlockchainWalletsPaymentsCryptoIndexerNFTDeveloper PlatformGaming

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 48.0/100 · developing
Contract Quality 14.2 / 25
Developer Ergonomics 15.2 / 20
Commercial Clarity 4.7 / 20
Operational Transparency 5.8 / 13
Governance 0.0 / 12
Discoverability 10.0 / 10
Agent readiness — 61/100 · agent native
Machine-Readable Contract 18 / 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 6 / 6
Agent Skills 5 / 5
Well-Known Catalog 4 / 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/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.

MCP Servers 1

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

sequence-mcp.yml

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

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: '0.20'
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
  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
  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
  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: 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