Euler Finance Chains API

openapi: 3.1.0
info:
  title: Euler Data API (V3) Accounts Chains API
  version: 3.0.0
  description: "API specification for Euler Data v3. This spec defines the current\nresource-oriented contract for the platform, with emphasis on consistent\nschemas, predictable REST semantics, caching, observability, and a uniform\ndeveloper experience.\n\nMigration notes\n- Euler Data v3 is not a path-for-path clone of v1/v2. Some endpoints map\n  directly, some require multiple v3 calls, and some legacy aggregates were\n  intentionally removed.\n- The live [migration guide](/v3/docs/migration) explains how legacy v1/v2\n  endpoints and payloads map into the v3 resource model.\n- Important semantic changes:\n  - Vault base APY and rewards APY are exposed separately in v3.\n  - Account positions are flattened into account-vault rows instead of the\n    legacy nested sub-account shape.\n  - All supported API paths live under `/v3`; legacy paths return `410`.\n  - Summary endpoints prefer smaller, focused resources over large\n    BFF-style payloads.\n\nBase path: /v3\n\nConventions\n- JSON field naming: camelCase\n- Addresses: accept lowercase or checksum; responses are EIP-55 checksummed\n- Public APY values (`*Apy`, `apy*`): percent numbers with 6 decimal places (e.g., 5.123456 = 5.123456%)\n- Contract interest-rate fields (`borrowAPY`, `supplyAPY` in `interestRates`): decimal strings in contract fraction units\n- Ratios (utilization, LTV, etc.): numbers with 6 decimal places\n- Response timestamps: ISO-8601 strings (UTC). Some legacy fields still expose unix\n  seconds for compatibility and include `*Iso` companions.\n- Query time ranges: unix seconds (from/to)\n\nUnit policy\n- v3 separates market metadata from contract verdicts by both name and type.\n- Market-normalized USD prices and USD values are JSON numbers. These are values\n  derived from off-chain pricing, cached price snapshots, or API-level market math.\n  This includes `/v3/prices`, token price routes, vault/earn/protocol USD totals,\n  portfolio market values, portfolio USD liquidation/risk fields such as\n  `liabilityValueUsd`, `totalCollateralValueUsd`, `borrowLiquidationPriceUsd`,\n  and `collateralLiquidationPricesUsd`, and vault holder `assetsUsd`.\n- Contract-derived oracle and raw account-liquidity verdict values are exact strings.\n  These preserve the integer value used by contracts, normalized to 18 decimals\n  for API exposure. Oracle prices are quoted in the vault unit of account, which\n  can be USD, ETH, or another asset. This includes `/v3/oracles/prices`, raw\n  account-liquidity `liabilityValue` and `totalCollateralValue` objects,\n  `liabilityValueBorrowing`, `liabilityValueLiquidation`, and collateral verdict\n  values.\n- On-chain token quantities are bigint strings in their native unit scale. This\n  includes amounts, balances, shares, assets, borrows, reward amounts, liquidation\n  repay/yield amounts, and block numbers.\n- Caps are also bigint strings, but EVK caps are exposed as resolved underlying\n  asset-unit amounts rather than packed contract config words.\n- LTV config values use canonical basis-point strings. Legacy decimal aliases\n  may remain on config-history payloads for compatibility when explicitly named.\n\nRate limiting\n- Optional API keys for higher limits\n- Default limits are configurable; current defaults: free tier 100 req/min (IP-based)\n  and authenticated 1000 req/min (per API key), 60s window.\n- By default, proxy headers are not trusted for IP identity unless explicitly enabled.\n- Redis failures default to fail-closed (503) for strict enforcement; fail-open is opt-in.\n- RateLimit-* (IETF draft-6) and legacy X-RateLimit-* headers are returned.\n\nCORS\n- Public API responses use wildcard CORS, including preflight responses for unsafe methods.\n- Unsafe methods with request bodies must use a JSON media type.\n\nCaching\n- Cache-Control headers are returned for cacheable endpoints.\n- Defaults (may be adjusted in config):\n  - Prices: 300s\n  - APYs: 600s\n  - Rewards: 900s\n  - General responses: 60s (short 30s, long 300s)\n\nErrors\n- All errors use a standard envelope: { error: { code, message, requestId, details? } }\n- Domain error codes are documented in this spec.\n- JSON request bodies must use `Content-Type: application/json` or another `application/*+json` media type.\n- Request bodies larger than 1 MiB are rejected before route parsing with `413 PAYLOAD_TOO_LARGE`.\n"
servers:
- url: /
  description: Current environment
security: []
tags:
- name: Chains
  description: Chain inventory and per-chain protocol summaries. These replace ad-hoc chain-level aggregates from legacy APIs with explicit, cacheable resources.
paths:
  /v3/chains:
    get:
      tags:
      - Chains
      summary: List supported chains
      x-status: implemented
      x-cache-ttl: 300
      responses:
        '200':
          description: Chains
          headers:
            Cache-Control:
              $ref: '#/components/headers/Cache-Control'
            X-Request-Id:
              $ref: '#/components/headers/X-Request-Id'
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Chain'
                  meta:
                    $ref: '#/components/schemas/PaginationMeta'
      operationId: getChains
  /v3/chains/{chainId}/stats:
    get:
      tags:
      - Chains
      summary: Chain-level stats
      description: Returns chain-scoped EVK lending aggregates. `earnTotalAssetsUsd` is reported separately and is not part of `totalSuppliedUsd` or `utilization`.
      x-status: implemented
      x-cache-ttl: 60
      parameters:
      - $ref: '#/components/parameters/ChainIdPath'
      responses:
        '200':
          description: Chain stats
          headers:
            Cache-Control:
              $ref: '#/components/headers/Cache-Control'
            X-Request-Id:
              $ref: '#/components/headers/X-Request-Id'
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    $ref: '#/components/schemas/ChainStats'
                  meta:
                    $ref: '#/components/schemas/PaginationMeta'
      operationId: getChainsByChainIdStats
  /v3/chains/{chainId}/borrowable-vaults:
    get:
      tags:
      - Chains
      summary: Borrowable vaults for a chain
      deprecated: true
      description: Legacy location for this collection.
      x-status: implemented
      x-cache-ttl: 300
      parameters:
      - $ref: '#/components/parameters/ChainIdPath'
      responses:
        '200':
          description: Borrowable vaults
          headers:
            Cache-Control:
              $ref: '#/components/headers/Cache-Control'
            X-Request-Id:
              $ref: '#/components/headers/X-Request-Id'
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      type: string
                  meta:
                    $ref: '#/components/schemas/PaginationMeta'
      operationId: getChainsByChainIdBorrowableVaults
components:
  parameters:
    ChainIdPath:
      name: chainId
      in: path
      required: true
      schema:
        type: integer
  schemas:
    PaginationMeta:
      type: object
      required:
      - timestamp
      properties:
        total:
          type: integer
          description: Exact total count when the endpoint provides one.
        hasMore:
          type: boolean
          description: Indicates whether another page exists beyond the current page.
        offset:
          type: integer
        limit:
          type: integer
          description: Echoed page size after endpoint-side clamping.
        timestamp:
          type: string
          format: date-time
        chainId:
          type: string
          description: Comma-separated chain IDs for multi-chain responses.
    ProtocolStats:
      type: object
      description: EVK lending aggregates across the selected chains, with Earn TVL reported separately.
      properties:
        totalSuppliedUsd:
          type: number
          description: Total EVK lending supply in USD. This is the sum of vault `cash + totalBorrows` valued in USD and excludes Earn vault assets.
        totalBorrowedUsd:
          type: number
          description: Total EVK lending borrows in USD across the selected chains.
        earnTotalAssetsUsd:
          type: number
          description: Total Earn vault assets in USD. Reported separately and not included in `totalSuppliedUsd` or `utilization`.
        utilization:
          type: number
          description: EVK lending utilization, computed as `totalBorrowedUsd / totalSuppliedUsd`. Earn assets are excluded from the denominator.
        vaultCount:
          type: integer
        chainCount:
          type: integer
    Chain:
      type: object
      required:
      - id
      - name
      properties:
        id:
          type: integer
        name:
          type: string
        status:
          type: string
          nullable: true
          description: Optional chain health status.
    ChainStats:
      allOf:
      - $ref: '#/components/schemas/ProtocolStats'
      - type: object
        required:
        - chainId
        properties:
          chainId:
            type: integer
            description: Chain ID for the returned chain-scoped aggregate.
  headers:
    Cache-Control:
      description: Cache policy for this response.
      schema:
        type: string
    X-Request-Id:
      description: Request identifier for tracing.
      schema:
        type: string
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
      description: API key authentication (optional; higher rate limits).
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: API key
      description: 'Alternative to X-API-Key using Authorization: Bearer <key>'
    AdminSecret:
      type: apiKey
      in: header
      name: X-Admin-Secret
      description: Admin secret (server-to-server) for API key management.
    PlatformSession:
      type: apiKey
      in: cookie
      name: euler_platform_session
      description: Signed, httpOnly platform-operator browser session cookie.
    PlatformCsrf:
      type: apiKey
      in: header
      name: X-CSRF-Token
      description: Double-submit CSRF token required for unsafe cookie-authenticated methods.