Alchemy API (with API Key)

Reference and integration guide for wiring Alchemy APIs into application code using a standard API key. This file alone is enough to ship a basic integration; the references/ directory contains deeper coverage of every product surface.

When to use this skill

Use alchemy-api when all of the following are true:

• The user is wiring Alchemy into application code (server, backend, dApp, worker, script) that runs outside the current agent session
• They have, or are willing to create, an Alchemy API key (free at dashboard.alchemy.com)

This is the preferred app-integration path for normal server/backend usage.

When to use a different skill

Do not use this skill to run ad-hoc live queries from inside the agent session — that's the alchemy-cli / alchemy-mcp path. This skill is for code that ships.

Mandatory preflight gate

Before writing application code or making any network call:

1. Confirm the user is building application code (not asking the agent to run a live query). If the user is asking for live work, redirect to alchemy-cli (preferred) or alchemy-mcp.
2. Check $ALCHEMY_API_KEY is set (e.g. echo $ALCHEMY_API_KEY).
3. If $ALCHEMY_API_KEY is unset or empty, take the first of these that applies:
   • CLI bridge (recommended if @alchemy/cli is installed locally): the CLI can fetch a key from the user's Alchemy account so they never have to leave the terminal. See Bridging from the CLI to an API key below.
   • Tell the user they can create a free API key at https://dashboard.alchemy.com/, or
   • Switch to the agentic-gateway skill (x402/MPP gateway, wallet-based auth, no API key needed).

You MUST NOT call any keyless or public fallback (including .../v2/demo) unless the user explicitly asks for that endpoint. No public RPC endpoints (publicnode, llamarpc, cloudflare-eth, etc.) as a fallback.

Bridging from the CLI to an API key

If @alchemy/cli is installed locally (verify with command -v alchemy), use it to obtain a key without leaving the terminal and persist it to the project's .env file so it survives across terminal sessions and is available to the app at runtime.

Security: NEVER echo, print, or otherwise surface the extracted API key value in conversation output. Refer to it only as $ALCHEMY_API_KEY after exporting. Treat it the same as a password.

# 1. Try to read a cached key from the CLI config (read-only, safe to run non-interactively).
KEY="$(alchemy --no-interactive --json --reveal config get api-key 2>/dev/null | jq -r .value)"

# 2. If empty/null (no key cached yet), run the interactive flow.
#    Note: auth login opens a browser and apps select shows a picker, so do NOT pass
#    --no-interactive here. If you already know the app id, pass it explicitly to skip
#    the picker: `alchemy --no-interactive --json apps select <id>`.
if [ -z "$KEY" ] || [ "$KEY" = "null" ]; then
  alchemy auth login              # opens browser; derives auth credentials
  alchemy --json apps select      # interactive picker (omit --no-interactive so it can render)
  KEY="$(alchemy --no-interactive --json --reveal config get api-key | jq -r .value)"
fi

# 3. Persist to the project's .env (standard practice for app code so the key
#    survives terminal restarts and is loaded by dotenv / framework env loaders).
#    Use .env.local instead if your framework expects that (e.g. Next.js).
ENV_FILE=".env"   # or ".env.local" depending on the project convention
touch "$ENV_FILE"
if grep -q '^ALCHEMY_API_KEY=' "$ENV_FILE"; then
  # Replace existing line in-place (portable across BSD/GNU sed)
  sed -i.bak "s|^ALCHEMY_API_KEY=.*|ALCHEMY_API_KEY=$KEY|" "$ENV_FILE" && rm "$ENV_FILE.bak"
else
  echo "ALCHEMY_API_KEY=$KEY" >> "$ENV_FILE"
fi

# 4. Make sure the env file is git-ignored.
grep -qxF "$ENV_FILE" .gitignore 2>/dev/null || echo "$ENV_FILE" >> .gitignore

# 5. Also export to the current shell so the agent can immediately call the API.
export ALCHEMY_API_KEY="$KEY"

Why we persist to .env: without it, the key is only set for the current shell session and disappears when the terminal tab closes. App code typically loads .env via dotenv (Node), python-dotenv (Python), direnv, or framework-native loaders (Next.js, Vite, Bun, Deno, Rails, etc.), so writing to .env is the canonical way to make the key durable for both npm run dev and the deployed app's local copy.

Why this whole flow works: the CLI is a runtime executor (alchemy-cli skill). When the user has it installed, you can use it to provision the credential that this app-code skill needs, write it to a place the application will load, then hand off to the rest of the alchemy-api flow. After step 5, continue with the Base URLs + auth and Quickstart below.

Gotcha: if auth login succeeded but config get api-key still returns "not found," the CLI's setup status may have falsely reported complete: true with only an auth_token. Re-run alchemy --json apps select (or pass an explicit <id> with --no-interactive) to bind a default app, then retry. See the alchemy-cli skill for the same gotcha documented under Preflight.

Summary

A self-contained guide for AI agents integrating Alchemy APIs using an API key. This file alone should be enough to ship a basic integration. Use the reference files for depth, edge cases, and advanced workflows.

Developers can always create a free API key at https://dashboard.alchemy.com/.

Do this first

1. Confirm app-integration scope (see Mandatory preflight gate).
2. Choose the right product using the Endpoint selector below.
3. Use the Base URLs + auth table for the correct endpoint and headers.
4. Copy a Quickstart example and test against a testnet first.

Base URLs + auth (cheat sheet)

Endpoint selector (top tasks)

One-file quickstart (copy/paste)

No API key? Use the agentic-gateway skill instead. Replace API-key URLs with https://x402.alchemy.com/eth-mainnet/v2 and add Authorization: SIWE <token> (or SIWS <token> for a Solana wallet). See the agentic-gateway skill for setup.

EVM JSON-RPC (read)

curl -s https://eth-mainnet.g.alchemy.com/v2/$ALCHEMY_API_KEY \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

Token balances

curl -s https://eth-mainnet.g.alchemy.com/v2/$ALCHEMY_API_KEY \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"alchemy_getTokenBalances","params":["0x00000000219ab540356cbb839cbe05303d7705fa"]}'

Transfer history

curl -s https://eth-mainnet.g.alchemy.com/v2/$ALCHEMY_API_KEY \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"alchemy_getAssetTransfers","params":[{"fromBlock":"0x0","toBlock":"latest","toAddress":"0x00000000219ab540356cbb839cbe05303d7705fa","category":["erc20"],"withMetadata":true,"maxCount":"0x3e8"}]}'

NFT ownership

curl -s "https://eth-mainnet.g.alchemy.com/nft/v3/$ALCHEMY_API_KEY/getNFTsForOwner?owner=0x00000000219ab540356cbb839cbe05303d7705fa"

Prices (spot)

curl -s "https://api.g.alchemy.com/prices/v1/$ALCHEMY_API_KEY/tokens/by-symbol?symbols=ETH&symbols=USDC"

Prices (historical)

curl -s -X POST "https://api.g.alchemy.com/prices/v1/$ALCHEMY_API_KEY/tokens/historical" \
  -H "Content-Type: application/json" \
  -d '{"symbol":"ETH","startTime":"2024-01-01T00:00:00Z","endTime":"2024-01-02T00:00:00Z"}'

Create Notify webhook

curl -s -X POST "https://dashboard.alchemy.com/api/create-webhook" \
  -H "Content-Type: application/json" \
  -H "X-Alchemy-Token: $ALCHEMY_NOTIFY_AUTH_TOKEN" \
  -d '{"network":"ETH_MAINNET","webhook_type":"ADDRESS_ACTIVITY","webhook_url":"https://example.com/webhook","addresses":["0x00000000219ab540356cbb839cbe05303d7705fa"]}'

Verify webhook signature (Node)

import crypto from "crypto";

export function verify(rawBody: string, signature: string, secret: string) {
  const hmac = crypto.createHmac("sha256", secret).update(rawBody).digest("hex");
  return crypto.timingSafeEqual(Buffer.from(hmac), Buffer.from(signature));
}

Network naming rules

• Data APIs and JSON-RPC use lowercase network enums like eth-mainnet.
• Notify API uses uppercase enums like ETH_MAINNET.

Pagination + limits (cheat sheet)

Common token addresses

Failure modes + retries

• HTTP 429 means rate limit. Use exponential backoff with jitter.
• JSON-RPC errors come in error fields even with HTTP 200.
• Use pageKey to resume pagination after failures.
• De-dupe websocket events on reconnect.

Skill map

For the complete index of all 90+ reference files organized by product area (Node, Data, Webhooks, Solana, Sui gRPC, Wallets, Rollups, Recipes, Operational, Ecosystem), see references/skill-map.md.

Quick category overview:

• Node: JSON-RPC, WebSocket, Debug, Trace, Enhanced APIs, Utility
• Data: NFT, Portfolio, Prices, Simulation, Token, Transfers
• Webhooks: Address Activity, Custom (GraphQL), NFT Activity, Payloads, Signatures
• Solana: JSON-RPC, DAS, Yellowstone gRPC (streaming), Wallets
• Sui gRPC: Objects, Transactions, Balances, Move Packages, Name Service, Subscriptions, Signature Verification
• Wallets: Account Kit, Bundler, Gas Manager, Wallet APIs (formerly "Smart Wallets")
• Rollups: L2/L3 deployment overview
• Recipes: 10 end-to-end integration workflows
• Operational: Auth, Rate Limits, Monitoring, Best Practices
• Ecosystem: viem, ethers, wagmi, Hardhat, Foundry, Anchor, and more

Handing off to other skills

Troubleshooting

API key not working

• Verify $ALCHEMY_API_KEY is set: echo $ALCHEMY_API_KEY
• Confirm the key is valid at dashboard.alchemy.com
• Check if allowlists restrict the key to specific IPs/domains (see references/operational-allowlists.md)

HTTP 429 (rate limited)

• Use exponential backoff with jitter before retrying
• Check your compute unit budget in the Alchemy dashboard
• See references/operational-rate-limits-and-compute-units.md for limits per plan

Wrong network slug

• Data APIs and JSON-RPC use lowercase: eth-mainnet, base-mainnet
• Notify API uses uppercase: ETH_MAINNET, BASE_MAINNET
• See references/operational-supported-networks.md for the full list

JSON-RPC error with HTTP 200

• Alchemy returns JSON-RPC errors inside the error field even with a 200 status code
• Always check response.error in addition to HTTP status

Official links

• Developer docs
• Get Started guide
• Create a free API key