diff --git a/src/ddo/Asset.ts b/src/ddo/Asset.ts
new file mode 100644
index 00000000..180aeb0c
--- /dev/null
+++ b/src/ddo/Asset.ts
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+import { DDO } from './DDO'
+
+export interface AssetNft {
+  /**
+   * Contract address of the deployed ERC721 NFT contract.
+   * @type {string}
+   */
+  address: string
+
+  /**
+   * Name of NFT set in contract.
+   * @type {string}
+   */
+  name: string
+
+  /**
+   * Symbol of NFT set in contract.
+   * @type {string}
+   */
+  symbol: string
+
+  /**
+   * ETH account address of the NFT owner.
+   * @type {string}
+   */
+  owner: string
+
+  /**
+   * State of the asset reflecting the NFT contract value.
+   * 0	Active.
+   * 1	End-of-life.
+   * 2	Deprecated (by another asset).
+   * 3	Revoked by publisher.
+   * 4	Ordering is temporary disabled.
+   * @type {number}
+   */
+  state: 0 | 1 | 2 | 3 | 4
+
+  /**
+   * Contains the date of NFT creation.
+   * @type {string}
+   */
+  created: string
+}
+
+export interface AssetDatatoken {
+  /**
+   * Contract address of the deployed ERC20 contract.
+   * @type {string}
+   */
+  address: string
+
+  /**
+   * Name of NFT set in contract.
+   * @type {string}
+   */
+  name: string
+
+  /**
+   * Symbol of NFT set in contract.
+   * @type {string}
+   */
+  symbol: string
+
+  /**
+   * ID of the service the datatoken is attached to.
+   * @type {string}
+   */
+  serviceId: string
+}
+
+export interface AssetLastEvent {
+  tx: string
+  block: number
+  from: string
+  contract: string
+  datetime: string
+}
+
+export class Asset extends DDO {
+  /**
+   * Contains information about the ERC721 NFT contract which represents the intellectual property of the publisher.
+   * @type {string}
+   */
+  nft: AssetNft
+
+  /**
+   * Contains information about the ERC20 datatokens attached to asset services.
+   * @type {string}
+   */
+  datatokens: AssetDatatoken[]
+
+  /**
+   * Contains information about the last transaction that created or updated the DDO.
+   * @type {string}
+   */
+  event: AssetLastEvent
+
+  /**
+   * The stats section contains different statistics fields.
+   * @type {string}
+   */
+  stats: {
+    /**
+     * How often an asset was consumed, meaning how often it was either downloaded or used as part of a compute job.
+     * @type {string}
+     */
+    consume: number
+
+    /**
+     * If asset is listed in purgatory and reason.
+     * @type {string}
+     */
+    isInPurgatory: string
+  }
+}
diff --git a/src/ddo/Credentials.ts b/src/ddo/Credentials.ts
new file mode 100644
index 00000000..9133f74e
--- /dev/null
+++ b/src/ddo/Credentials.ts
@@ -0,0 +1,9 @@
+export interface Credential {
+  type: string
+  values: string[]
+}
+
+export interface Credentials {
+  allow: Credential[]
+  deny: Credential[]
+}
diff --git a/src/ddo/DDO.ts b/src/ddo/DDO.ts
new file mode 100644
index 00000000..8808b384
--- /dev/null
+++ b/src/ddo/DDO.ts
@@ -0,0 +1,54 @@
+import { Service } from './Service'
+import { Metadata } from './Metadata'
+import { Credentials } from './Credentials'
+
+/**
+ * DID Descriptor Object.
+ * Contains metadata about the asset, and define access in at least one service.
+ */
+export class DDO {
+  /**
+   * Contexts used for validation.
+   * @type {string[]}
+   */
+  public '@context': string[]
+
+  /**
+   * DID, descentralized ID.
+   * Computed as sha256(address of ERC721 contract + chainId)
+   * @type {string}
+   */
+  public id: string
+
+  /**
+   * Version information in SemVer notation
+   * referring to the DDO spec version
+   * @type {string}
+   */
+  public version: string
+
+  /**
+   * ChainId of the network the DDO was published to.
+   * @type {number}
+   */
+  public chainId: number
+
+  /**
+   * Stores an object describing the asset.
+   * @type {Metadata}
+   */
+  public metadata: Metadata
+
+  /**
+   * Stores an array of services defining access to the asset.
+   * @type {Service[]}
+   */
+  public services: Service[]
+
+  /**
+   * Describes the credentials needed to access a dataset
+   * in addition to the services definition.
+   * @type {Credentials}
+   */
+  public credentials?: Credentials
+}
diff --git a/src/ddo/Metadata.ts b/src/ddo/Metadata.ts
new file mode 100644
index 00000000..425592b8
--- /dev/null
+++ b/src/ddo/Metadata.ts
@@ -0,0 +1,127 @@
+export interface MetadataAlgorithm {
+  /**
+   * Language used to implement the software.
+   * @type {string}
+   */
+  language?: string
+
+  /**
+   * Version of the software preferably in SemVer notation.
+   * @type {string}
+   */
+  version?: string
+
+  /**
+   * Object describing the Docker container image.
+   * @type {Object}
+   */
+  container: {
+    /**
+     * The command to execute, or script to run inside the Docker image.
+     * @type {string}
+     */
+    entrypoint: string
+
+    /**
+     * Name of the Docker image.
+     * @type {string}
+     */
+    image: string
+
+    /**
+     * Tag of the Docker image.
+     * @type {string}
+     */
+    tag: string
+
+    /**
+     * Checksum of the Docker image.
+     * @type {string}
+     */
+    checksum: string
+  }
+}
+
+export interface Metadata {
+  /**
+   * Contains the date of publishing in ISO Date Time
+   * @type {string}
+   */
+  created: string
+
+  /**
+   * Contains the the date of last update in ISO Date Time
+   * @type {string}
+   */
+  updated: string
+
+  /**
+   * Descriptive name or title of the asset.
+   * @type {string}
+   */
+  name: string
+
+  /**
+   * Details of what the resource is.
+   * @type {string}
+   */
+  description: string
+
+  /**
+   * Asset type. Includes "dataset" (e.g. csv file), "algorithm" (e.g. Python script).
+   * Each type needs a different subset of metadata attributes.
+   * @type {'dataset' | 'algorithm'}
+   */
+  type: 'dataset' | 'algorithm'
+
+  /**
+   * Name of the entity generating this data (e.g. Tfl, Disney Corp, etc.).
+   * @type {string}
+   */
+  author: string
+
+  /**
+   * Short name referencing the license of the asset.
+   * If it’s not specified, the following value will be added: “No License Specified”.
+   * @type {string}
+   */
+  license: string
+
+  /**
+   * Mapping of URL strings for data samples, or links to find out more information.
+   * Links may be to either a URL or another asset.
+   * @type {string[]}
+   */
+  links?: string[]
+
+  /**
+   * Mapping of URL strings for data samples, or links to find out more information.
+   * Links may be to either a URL or another asset.
+   * @type {string[]}
+   */
+  tags?: string[]
+
+  /**
+   * The party holding the legal copyright. Empty by default.
+   * @type {string}
+   */
+  copyrightHolder?: string
+
+  /**
+   *The language of the content. Use one of the language codes from the IETF BCP 47 standard
+   * @type {string}
+   */
+  contentLanguage?: string
+
+  /**
+   * Information about asset of typealgorithm
+   * @type {MetadataAlgorithm}
+   */
+  algorithm?: MetadataAlgorithm
+
+  /**
+   * Stores additional information, this is customizable by publisher
+   * @type {any}
+   */
+  additionalInformation?: any
+}
diff --git a/src/ddo/Service.ts b/src/ddo/Service.ts
new file mode 100644
index 00000000..c5b447b7
--- /dev/null
+++ b/src/ddo/Service.ts
@@ -0,0 +1,145 @@
+export interface PublisherTrustedAlgorithm {
+  /**
+   * The DID of the algorithm which is trusted by the publisher.
+   * @type {string}
+   */
+  did: string
+
+  /**
+   * Hash of algorithm’s files section.
+   * @type {string}
+   */
+  filesChecksum: string
+
+  /**
+   * Hash of algorithm’s metadata.algorithm.container section.
+   * @type {string}
+   */
+  containerSectionChecksum: string
+}
+
+export interface ServiceComputeOptions {
+  /**
+   * Namespaced used for the compute job.
+   * @type {string}
+   */
+  namespace: string
+
+  /**
+   * Maximum number of CPUs allocated for a job
+   * @type {number}
+   */
+  cpu?: number
+
+  /**
+   * Maximum number of GPUs allocated for a job
+   * @type {number}
+   */
+  gpu?: number
+
+  /**
+   * Type of GPU (if any)
+   * @type {string}
+   */
+  gpuType?: string
+
+  /**
+   * Maximum amount of memory allocated for a job.
+   * You can express memory as a plain integer or as a fixed-point number using one of these suffixes: E, P, T, G, M, k.
+   * You can also use the power-of-two equivalents: Ei, Pi, Ti, Gi, Mi, Ki.
+   * For example, the following represent roughly the same value: 128974848, 129e6, 129M, 123Mi
+   * @type {string}
+   */
+  memory?: string
+
+  /**
+   * Amount of disk space allocated.
+   * You can express it as a plain integer or as a fixed-point number using one of these suffixes: E, P, T, G, M, k.
+   * You can also use the power-of-two equivalents: Ei, Pi, Ti, Gi, Mi, Ki.
+   * @type {string}
+   */
+  volumeSize?: string
+
+  /**
+   * If true, any passed raw text will be allowed to run.
+   * Useful for an algorithm drag & drop use case, but increases risk of data escape through malicious user input.
+   * Should be false by default in all implementations.
+   * @type {boolean}
+   */
+  allowRawAlgorithm: boolean
+
+  /**
+   * If true, the algorithm job will have network access.
+   * @type {boolean}
+   */
+  allowNetworkAccess: boolean
+
+  /**
+   * If empty, then any published algorithm is allowed.
+   * Otherwise, only published algorithms by some publishers are allowed
+   * @type {string[]}
+   */
+  publisherTrustedAlgorithmPublishers: string[]
+
+  /**
+   * If empty, then any published algorithm is allowed. (see below)
+   * @type {PublisherTrustedAlgorithm[]}
+   */
+  publisherTrustedAlgorithms: PublisherTrustedAlgorithm[]
+}
+
+export interface Service {
+  /**
+   * Unique ID
+   * @type {string}
+   */
+  id: string
+
+  /**
+   * Type of service (access, compute, wss.
+   * @type {string}
+   */
+  type: 'access' | 'compute' | string
+
+  /**
+   * Encrypted file URLs.
+   * @type {string}
+   */
+  files: string
+
+  /**
+   * Datatoken address
+   * @type {string}
+   */
+  datatokenAddress: string
+
+  /**
+   * Provider URL (schema + host).
+   * @type {string}
+   */
+  serviceEndpoint: string
+
+  /**
+   * Describing how long the service can be used after consumption is initiated.
+   * @type {string}
+   */
+  timeout: string
+
+  /**
+   * Service friendly name
+   * @type {string}
+   */
+  name?: string
+
+  /**
+   * Service description
+   * @type {string}
+   */
+  description?: string
+
+  /**
+   * If service is of typecompute, holds information about the compute-related privacy settings & resources.
+   * @type {ServiceComputeOptions}
+   */
+  compute?: ServiceComputeOptions
+}
diff --git a/src/ddo/index.ts b/src/ddo/index.ts
new file mode 100644
index 00000000..06eb4fc6
--- /dev/null
+++ b/src/ddo/index.ts
@@ -0,0 +1,5 @@
+export * from './DDO'
+export * from './Asset'
+export * from './Service'
+export * from './Credentials'
+export * from './Metadata'