Add batch-transfer example app (TypeScript + Go) by gregnazario · Pull Request #21 · aptos-labs/aptos-sdk-specs

gregnazario · 2026-02-21T16:25:53Z

Summary

Adds examples/batch-transfer/ with reference implementations in TypeScript and Go
Teaches the core batch-submission pattern: fetch sequence number once, build + sign all transactions locally, then submit in parallel
Includes retry with exponential backoff on confirmation
Produces identical JSON summary output across both languages for easy cross-SDK comparison

Key pattern demonstrated

# Naive (N round-trips):
for each tx: fetch seq_num → build → submit

# This example (1 round-trip):
fetch seq_num once
for each tx (local): build with (seq_num + i) → sign
submit all in parallel

Test plan

cd examples/batch-transfer/typescript && bun install && bun src/main.ts runs against devnet
cd examples/batch-transfer/go && go run main.go runs against devnet
Both produce the 4-phase output and JSON summary
--count and --network flags work as expected
TypeScript: bunx tsc --noEmit passes
Go: go vet ./... and go build ./... pass

Demonstrates sending N APT transfers in parallel using the key pattern of fetching the sender's sequence number once and incrementing locally, avoiding N network round-trips and enabling true parallel submission. Features shown: - Account generation and faucet funding - Gas price estimation - Sequence number pre-fetching (fetch once, increment locally) - Local build + sign before any network submission - Parallel dispatch (Promise.allSettled / goroutines + WaitGroup) - Exponential backoff retry on confirmation - Structured JSON summary output for cross-SDK comparison CLI: --count N --network devnet|testnet|mainnet (default: devnet, 10 txs)

Copilot

Pull request overview

Adds a new examples/batch-transfer/ reference example demonstrating the “fetch sequence number once, build+sign locally, submit in parallel, then confirm with retry” batch-submission pattern in both TypeScript (ts-sdk) and Go (aptos-go-sdk), with aligned 4-phase console output and a shared JSON summary shape for cross-SDK comparison.

Changes:

Add TypeScript batch-transfer app (Bun-based) with parallel submit and confirmation retry.
Add Go batch-transfer app with goroutine-based parallel submit and confirmation retry.
Add documentation for the batch-transfer example and register it in examples/README.md.

Reviewed changes

Copilot reviewed 7 out of 9 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
examples/batch-transfer/typescript/src/main.ts	Implements TS batch build/sign/submit/confirm flow and JSON summary output.
examples/batch-transfer/typescript/package.json	Declares Bun runnable example and ts-sdk dependency.
examples/batch-transfer/typescript/tsconfig.json	Adds strict TS compilation config for the example.
examples/batch-transfer/typescript/bun.lock	Locks Bun dependencies for reproducible installs.
examples/batch-transfer/go/main.go	Implements Go batch build/sign/submit/confirm flow and JSON summary output.
examples/batch-transfer/go/go.mod	Adds standalone Go module for the example pinned to aptos-go-sdk.
examples/batch-transfer/go/go.sum	Locks Go dependency checksums.
examples/batch-transfer/README.md	Documents the pattern, usage, expected output, and CLI options.
examples/README.md	Adds the new example to the examples index and describes example design principles.

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examples/batch-transfer/README.md

Copilot · 2026-02-22T21:33:22Z

examples/batch-transfer/typescript/src/main.ts

+  // Fund the sender via the devnet/testnet faucet
+  const fundResult = await aptos.fundAccount({
+    accountAddress: sender.accountAddress,
+    amount: FUND_AMOUNT_OCTAS,
+  });


--network advertises mainnet, but this example always generates a fresh sender and funds it via aptos.fundAccount(), which won't work on mainnet (no faucet). Consider either rejecting mainnet with a clear error, or supporting mainnet by requiring a user-provided funded sender key (env var / flag) and skipping faucet funding.

examples/batch-transfer/typescript/src/main.ts

Copilot · 2026-02-22T21:33:23Z

examples/batch-transfer/go/main.go

+	count := flag.Int("count", 10, "Number of transactions to send")
+	networkName := flag.String("network", "devnet", "Network: devnet, testnet, or mainnet")
+	flag.Parse()
+


--count is not validated. A negative value (e.g. --count=-1) will cause make(..., *count) to panic when creating slices later. Consider validating *count >= 1 immediately after flag.Parse() and exiting with a clear error message (to match the TypeScript example’s behavior).

Suggested change

if *count < 1 {

fmt.Fprintf(os.Stderr, "Invalid value for --count: %d (must be >= 1)\n", *count)

os.Exit(1)

}

Copilot · 2026-02-22T21:33:23Z

examples/batch-transfer/go/main.go

+	if err := client.Fund(sender.Address, fundAmountOctas); err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to fund sender: %v\n", err)
+		os.Exit(1)
+	}
+	fmt.Printf("  ✓ Funded sender with 1 APT\n")


--network includes mainnet, but this example always creates a new sender and calls client.Fund(...) (faucet), which won't work on mainnet. Consider rejecting mainnet with a clear error, or adding a mode that uses a user-supplied funded sender account and skips faucet funding.

examples/batch-transfer/go/main.go

- Reject --network mainnet with clear error in both TS and Go (example uses faucet, which does not exist on mainnet) - Validate --network against allowed values (devnet|testnet); exit with usage error on unknown input instead of silently falling back to devnet - Validate --count >= 1 in Go to prevent slice-allocation panic - Guard totalSpent against negative values in TypeScript with Math.max(0,...) (Go already had this guard via the uint64 underflow check) - Handle json.MarshalIndent error in Go instead of discarding it - Update docs/comments to remove mainnet from advertised options

Copilot

Pull request overview

Copilot reviewed 7 out of 9 changed files in this pull request and generated 1 comment.

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Copilot · 2026-02-22T22:28:17Z

examples/batch-transfer/typescript/src/main.ts

+  for (let i = 0; i < args.length; i++) {
+    if (args[i] === "--count" && i + 1 < args.length) {
+      count = parseInt(args[i + 1], 10);
+      if (isNaN(count) || count < 1) {
+        console.error("--count must be a positive integer");
+        process.exit(1);
+      }
+    }
+    if (args[i] === "--network" && i + 1 < args.length) {
+      network = args[i + 1];
+      if (network === "mainnet") {
+        console.error(
+          "Error: mainnet is not supported by this example because it funds a new account via faucet.",
+        );
+        console.error("To use mainnet, extend this example to accept a pre-funded sender key.");
+        process.exit(1);
+      }
+      if (!["devnet", "testnet"].includes(network)) {
+        console.error(`Error: unknown network "${network}". Allowed values: devnet, testnet`);
+        process.exit(1);
+      }
+    }
+  }


The CLI argument parsing doesn't skip the argument value after processing a flag. When an argument like "--count 20" is encountered, the loop should increment i to skip "20" after processing it. Otherwise, if someone passes "--count --network devnet", the "--network" will be treated as the count value (which would fail the parseInt), but in general this pattern could cause unexpected behavior. Consider adding "i++" after processing each flag's value, or use a proper argument parsing library.

Copilot

Pull request overview

Copilot reviewed 7 out of 9 changed files in this pull request and generated no new comments.

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gregnazario force-pushed the claude/hardcore-bardeen branch from 7ca89f6 to b50ad6b Compare February 21, 2026 22:05

Fix Prettier formatting on example READMEs

caedadb

gregnazario requested a review from Copilot February 22, 2026 21:29

Copilot started reviewing on behalf of gregnazario February 22, 2026 21:29 View session

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gregnazario added 2 commits February 22, 2026 16:51

Remove accidentally tracked Go binary

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gregnazario requested a review from Copilot February 22, 2026 22:23

Copilot started reviewing on behalf of gregnazario February 22, 2026 22:23 View session

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Fix CLI arg parser to consume value token after each flag

b9c0bb5

gregnazario requested a review from Copilot February 22, 2026 22:41

Copilot started reviewing on behalf of gregnazario February 22, 2026 22:41 View session

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gregnazario merged commit 7f945d7 into main Feb 23, 2026
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Add batch-transfer example app (TypeScript + Go)#21

Add batch-transfer example app (TypeScript + Go)#21
gregnazario merged 5 commits intomainfrom
claude/hardcore-bardeen

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+	if *count < 1 {
+		fmt.Fprintf(os.Stderr, "Invalid value for --count: %d (must be >= 1)\n", *count)
+		os.Exit(1)
+	}

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gregnazario commented Feb 21, 2026

Summary

Key pattern demonstrated

Test plan

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