diff --git a/packages/core/src/delegation.js b/packages/core/src/delegation.js
index 0564afe4..10ebdea3 100644
--- a/packages/core/src/delegation.js
+++ b/packages/core/src/delegation.js
@@ -1,6 +1,7 @@
 import * as UCAN from '@ipld/dag-ucan'
 import * as API from '@ucanto/interface'
 import * as Link from './link.js'
+import { base64 } from 'multiformats/bases/base64'
 
 /**
  * @deprecated
@@ -130,8 +131,61 @@ export class Delegation {
   iterate() {
     return it(this)
   }
+
+  /**
+   * @returns {API.DelegationJSON<this>}
+   */
+
+  toJSON() {
+    return toJSON(this)
+  }
+}
+
+/**
+ * @template {API.Delegation} T
+ * @param {T} delegation
+ * @returns {API.DelegationJSON<T>}
+ */
+export const toJSON = ({
+  cid,
+  issuer,
+  audience,
+  version,
+  signature,
+  proofs,
+  capabilities,
+  expiration,
+  notBefore,
+  nonce,
+  facts,
+}) => {
+  return {
+    ...Link.toJSON(cid),
+    version,
+    issuer: principalToJSON(issuer),
+    audience: principalToJSON(audience),
+    capabilities,
+    expiration: /** @type {API.UCAN.UTCUnixTimestamp|null} */ (expiration),
+    notBefore,
+    nonce,
+    facts,
+    proofs: proofs.map(proof =>
+      Link.toJSON(isDelegation(proof) ? proof.cid : proof)
+    ),
+    signature: {
+      '/': { bytes: base64.baseEncode(signature) },
+    },
+  }
 }
 
+/**
+ * @template {API.Principal} T
+ * @param {T} principal
+ * @returns {API.PrincipalJSON<T>}
+ */
+
+const principalToJSON = principal => principal.did()
+
 /**
  * @param {API.Delegation} delegation
  * @returns {IterableIterator<API.Delegation>}
diff --git a/packages/core/src/link.js b/packages/core/src/link.js
index b49b4574..30f41d26 100644
--- a/packages/core/src/link.js
+++ b/packages/core/src/link.js
@@ -1 +1,10 @@
 export * from 'multiformats/link'
+
+/**
+ * @template {import('multiformats').UnknownLink} Link
+ * @param {Link} link
+ */
+export const toJSON = link =>
+  /** @type {import('@ucanto/interface').LinkJSON<Link>} */ ({
+    '/': link.toString(),
+  })
diff --git a/packages/core/test/delegation.spec.js b/packages/core/test/delegation.spec.js
new file mode 100644
index 00000000..393318c7
--- /dev/null
+++ b/packages/core/test/delegation.spec.js
@@ -0,0 +1,125 @@
+import { delegate, UCAN } from '../src/lib.js'
+import { alice, bob, mallory, service as w3 } from './fixtures.js'
+import { assert, test } from './test.js'
+import { base64 } from 'multiformats/bases/base64'
+
+test('toJSON delegation', async () => {
+  const ucan = await delegate({
+    issuer: alice,
+    audience: w3,
+    capabilities: [
+      {
+        with: alice.did(),
+        can: 'test/echo',
+        nb: {
+          message: 'data:1',
+        },
+      },
+    ],
+    expiration: Infinity,
+  })
+
+  assert.equal(
+    JSON.stringify(ucan, null, 2),
+    JSON.stringify(
+      {
+        '/': ucan.cid.toString(),
+        version: ucan.version,
+        issuer: alice.did(),
+        audience: w3.did(),
+        capabilities: [
+          {
+            nb: {
+              message: 'data:1',
+            },
+            can: 'test/echo',
+            with: alice.did(),
+          },
+        ],
+        expiration: null,
+        facts: [],
+        proofs: [],
+        signature: {
+          '/': { bytes: base64.baseEncode(ucan.signature) },
+        },
+      },
+      null,
+      2
+    )
+  )
+})
+
+test('toJSON delegation chain', async () => {
+  const proof = await delegate({
+    issuer: bob,
+    audience: alice,
+    capabilities: [
+      {
+        with: bob.did(),
+        can: 'test/echo',
+      },
+    ],
+  })
+
+  const proof2 = await delegate({
+    issuer: mallory,
+    audience: alice,
+    capabilities: [
+      {
+        with: mallory.did(),
+        can: 'test/echo',
+      },
+    ],
+  })
+
+  const ucan = await delegate({
+    issuer: alice,
+    audience: w3,
+    capabilities: [
+      {
+        with: bob.did(),
+        can: 'test/echo',
+        nb: {
+          message: 'data:hi',
+        },
+      },
+    ],
+    proofs: [proof, proof2.cid],
+  })
+
+  assert.equal(
+    JSON.stringify(ucan, null, 2),
+    JSON.stringify(
+      {
+        '/': ucan.cid.toString(),
+        version: ucan.version,
+        issuer: alice.did(),
+        audience: w3.did(),
+        capabilities: [
+          {
+            nb: {
+              message: 'data:hi',
+            },
+            can: 'test/echo',
+            with: bob.did(),
+          },
+        ],
+        expiration: ucan.expiration,
+        facts: [],
+        proofs: [
+          {
+            '/': proof.cid.toString(),
+          },
+          {
+            '/': proof2.cid.toString(),
+          },
+        ],
+        signature: {
+          '/': { bytes: base64.baseEncode(ucan.signature) },
+        },
+      },
+      null,
+      2
+    )
+  )
+})
diff --git a/packages/interface/src/lib.ts b/packages/interface/src/lib.ts
index fcb0df55..65066881 100644
--- a/packages/interface/src/lib.ts
+++ b/packages/interface/src/lib.ts
@@ -18,7 +18,7 @@ import {
   MulticodecCode,
   SigAlg,
 } from '@ipld/dag-ucan'
-import { Link, Block as IPLDBlock } from 'multiformats'
+import { Link, Block as IPLDBlock, ToString, UnknownLink } from 'multiformats'
 import * as UCAN from '@ipld/dag-ucan'
 import {
   CanIssue,
@@ -143,6 +143,9 @@ export interface Delegation<C extends Capabilities = Capabilities> {
   readonly bytes: ByteView<UCAN.UCAN<C>>
   readonly data: UCAN.View<C>
 
+  version: UCAN.Version
+  signature: UCAN.Signature
+
   asCID: UCANLink<C>
 
   export(): IterableIterator<Block>
@@ -158,8 +161,34 @@ export interface Delegation<C extends Capabilities = Capabilities> {
   facts: Fact[]
   proofs: Proof[]
   iterate(): IterableIterator<Delegation>
+
+  toJSON(): DelegationJSON<this>
+}
+
+export interface DelegationJSON<T extends Delegation>
+  extends LinkJSON<T['cid']> {
+  version: T['version']
+  issuer: PrincipalJSON<T['issuer']>
+  audience: PrincipalJSON<T['audience']>
+  capabilities: T['capabilities']
+  expiration: UCAN.UTCUnixTimestamp | null
+  notBefore?: UCAN.UTCUnixTimestamp
+  nonce?: UCAN.Nonce
+  facts: Fact[]
+  proofs: LinkJSON[]
+  signature: { '/': { bytes: ToString<T['signature']> } }
+}
+
+export interface LinkJSON<T extends UnknownLink = UnknownLink> {
+  '/': ToString<T>
 }
 
+export interface BytesJSON<T extends Uint8Array = Uint8Array> {
+  '/': { bytes: ToString<T, 'm'> }
+}
+
+export type PrincipalJSON<T extends Principal> = DID & Phantom<T>
+
 /**
  * An Invocation represents a UCAN that can be presented to a service provider to
  * invoke or "exercise" a {@link Capability}. You can think of invocations as a
diff --git a/packages/validator/test/delegate.spec.js b/packages/validator/test/delegate.spec.js
index 16ff551e..31dadf89 100644
--- a/packages/validator/test/delegate.spec.js
+++ b/packages/validator/test/delegate.spec.js
@@ -1,9 +1,7 @@
-import { capability, DID, URI, Link, unknown, Schema } from '../src/lib.js'
-import { invoke, parseLink, delegate, UCAN } from '@ucanto/core'
+import { capability, DID, URI, Link, Schema } from '../src/lib.js'
+import { parseLink, delegate, UCAN } from '@ucanto/core'
 import * as API from '@ucanto/interface'
 import { Failure } from '../src/error.js'
-import { the } from '../src/util.js'
-import { CID } from 'multiformats'
 import { test, assert } from './test.js'
 import { alice, bob, mallory, service as w3 } from './fixtures.js'