diff --git a/chain/arweave.ts b/chain/arweave.ts
new file mode 100644
index 0000000..390af08
--- /dev/null
+++ b/chain/arweave.ts
@@ -0,0 +1,76 @@
+import '../common/eager_offset'
+import { Bytes } from '../common/collections'
+
+// Most types from this namespace are direct mappings or adaptations from:
+// https://github.com/ChainSafe/firehose-arweave/blob/master/proto/sf/arweave/type/v1/type.proto
+export namespace arweave {
+  /**
+   * A key-value pair for arbitrary metadata
+   */
+  export class Tag {
+    constructor(public name: Bytes, public value: Bytes) {}
+  }
+
+  export class ProofOfAccess {
+    constructor(
+      public option: string,
+      public txPath: Bytes,
+      public dataPath: Bytes,
+      public chunk: Bytes,
+    ) {}
+  }
+
+  /**
+   * An Arweave block.
+   */
+  export class Block {
+    constructor(
+      public timestamp: u64,
+      public lastRetarget: u64,
+      public height: u64,
+      public indepHash: Bytes,
+      public nonce: Bytes,
+      public previousBlock: Bytes,
+      public diff: Bytes,
+      public hash: Bytes,
+      public txRoot: Bytes,
+      public txs: Bytes[],
+      public walletList: Bytes,
+      public rewardAddr: Bytes,
+      public tags: Tag[],
+      public rewardPool: Bytes,
+      public weaveSize: Bytes,
+      public blockSize: Bytes,
+      public cumulativeDiff: Bytes,
+      public hashListMerkle: Bytes,
+      public poa: ProofOfAccess,
+    ) {}
+  }
+
+  /**
+   * An Arweave transaction
+   */
+  export class Transaction {
+    constructor(
+      public format: u32,
+      public id: Bytes,
+      public lastTx: Bytes,
+      public owner: Bytes,
+      public tags: Tag[],
+      public target: Bytes,
+      public quantity: Bytes,
+      public data: Bytes,
+      public dataSize: Bytes,
+      public dataRoot: Bytes,
+      public signature: Bytes,
+      public reward: Bytes,
+    ) {}
+  }
+
+  /**
+   * An Arweave transaction with block ptr
+   */
+  export class TransactionWithBlockPtr {
+    constructor(public tx: Transaction, public block: Block) {}
+  }
+}
diff --git a/global/global.ts b/global/global.ts
index 4ea2cc0..576e7f0 100644
--- a/global/global.ts
+++ b/global/global.ts
@@ -8,6 +8,7 @@ import {
   Wrapped,
 } from '../common/collections'
 import { JSONValue, Value } from '../common/value'
+import { arweave } from '../chain/arweave'
 import { ethereum } from '../chain/ethereum'
 import { near } from '../chain/near'
 import { cosmos } from '../chain/cosmos'
@@ -216,7 +217,25 @@ export enum TypeId {
   ```
   */
 
-  // Reserved discriminant space for a future blockchain type IDs: [2,500, 3,499]
+  // Reserved discriminant space for Tendermint type IDs: [2,500, 3,499]
+  ArweaveBlock = 2500,
+  ArweaveProofOfAccess = 2501,
+  ArweaveTag = 2502,
+  ArweaveTagArray = 2503,
+  ArweaveTransaction = 2504,
+  ArweaveTransactionArray = 2505,
+  ArweaveTransactionWithBlockPtr = 2506,
+  /*
+  Continue to add more Arweave type IDs here. e.g.:
+  ```
+  NextArweaveType = 2507,
+  AnotherArweaveType = 2508,
+  ...
+  LastArweaveType = 3499,
+  ```
+  */
+
+  // Reserved discriminant space for a future blockchain type IDs: [3,500, 4,499]
 }
 
 export function id_of_type(typeId: TypeId): usize {
@@ -528,6 +547,23 @@ export function id_of_type(typeId: TypeId): usize {
       return idof<cosmos.ValidatorUpdate>()
     case TypeId.CosmosVersionParams:
       return idof<cosmos.VersionParams>()
+    /**
+     * Arweave type ids
+     */
+    case TypeId.ArweaveBlock:
+      return idof<arweave.Block>()
+    case TypeId.ArweaveProofOfAccess:
+      return idof<arweave.ProofOfAccess>()
+    case TypeId.ArweaveTag:
+      return idof<arweave.Tag>()
+    case TypeId.ArweaveTagArray:
+      return idof<Array<arweave.Tag>>()
+    case TypeId.ArweaveTransaction:
+      return idof<arweave.Transaction>()
+    case TypeId.ArweaveTransactionArray:
+      return idof<Array<arweave.Transaction>>()
+    case TypeId.ArweaveTransactionWithBlockPtr:
+      return idof<arweave.TransactionWithBlockPtr>()
     default:
       return 0
   }
diff --git a/index.ts b/index.ts
index 9f18ccd..b5a0b50 100644
--- a/index.ts
+++ b/index.ts
@@ -1,5 +1,7 @@
 // Side-effect to evaluate eagerly the offset of stub AS runtime
 import './common/eager_offset'
+// Arweave support
+export * from './chain/arweave'
 // Ethereum support
 export * from './chain/ethereum'
 // NEAR support
diff --git a/test/test.js b/test/test.js
index f0dc167..8071bbf 100644
--- a/test/test.js
+++ b/test/test.js
@@ -29,6 +29,7 @@ async function main() {
   fs.copyFileSync('common/json.ts', 'test/temp_lib/common/json.ts')
   fs.copyFileSync('common/numbers.ts', 'test/temp_lib/common/numbers.ts')
   fs.copyFileSync('common/value.ts', 'test/temp_lib/common/value.ts')
+  fs.copyFileSync('chain/arweave.ts', 'test/temp_lib/chain/arweave.ts')
   fs.copyFileSync('chain/ethereum.ts', 'test/temp_lib/chain/ethereum.ts')
   fs.copyFileSync('chain/near.ts', 'test/temp_lib/chain/near.ts')
   fs.copyFileSync('chain/cosmos.ts', 'test/temp_lib/chain/cosmos.ts')
@@ -62,6 +63,7 @@ async function main() {
     fs.unlinkSync('test/temp_lib/common/numbers.ts')
     fs.unlinkSync('test/temp_lib/common/value.ts')
     fs.rmdirSync('test/temp_lib/common')
+    fs.unlinkSync('test/temp_lib/chain/arweave.ts')
     fs.unlinkSync('test/temp_lib/chain/ethereum.ts')
     fs.unlinkSync('test/temp_lib/chain/near.ts')
     fs.unlinkSync('test/temp_lib/chain/cosmos.ts')