Worker-proxy

A minimal Cloudflare Worker that accepts GET query params or POST JSON body params and rewrites them into a JSON-RPC request for Ankr:

• Destination base URL: https://rpc.ankr.com/multichain/[apikey]
• API key source: Worker secret ANKR_API_KEY (populated from GitHub repo secret in CI)

How it works

1. You call the Worker with either:
   • a GET request with query params, or
   • a POST request with a JSON body.
2. The Worker builds a JSON-RPC payload (default ankr_getAccountBalance).
3. The Worker forwards to https://rpc.ankr.com/multichain/${ANKR_API_KEY}.
4. The Worker returns the upstream response (with permissive CORS headers).

Query params

• walletAddress (required unless params is provided)
• blockchain (repeatable or comma-separated, default eth)
• nativeFirst (default true)
• onlyWhitelisted (default true)
• pageSize (default 10)
• pageToken (optional)
• method (default ankr_getAccountBalance)
• id (default 1)
• forwardMethod (POST default, or GET)
• params (optional raw JSON object string; if present, overrides field-based params)

POST JSON body fields

• walletAddress (required unless params is provided)
• blockchain (array or comma-separated string; default ["eth"])
• nativeFirst (default true)
• onlyWhitelisted (default true)
• pageSize (default 10)
• pageToken (optional)
• method (default ankr_getAccountBalance)
• id (default 1)
• forwardMethod (POST default, or GET)
• params (optional JSON object; if present, overrides field-based params)

Example request to Worker

Deployed (*.workers.dev)

curl --request GET \
  --url 'https://<your-worker>.workers.dev/?method=ankr_getAccountBalance&blockchain=eth&nativeFirst=true&onlyWhitelisted=true&pageSize=10&pageToken=1&walletAddress=0xE936e8FAf4A5655469182A49a505055B71C17604'

Local (wrangler dev)

After npm run dev, Wrangler usually serves at http://127.0.0.1:8787 (check the terminal output if yours differs):

curl --request GET \
  --url 'http://127.0.0.1:8787/?method=ankr_getAccountBalance&blockchain=eth&nativeFirst=true&onlyWhitelisted=true&pageSize=10&pageToken=1&walletAddress=0xE936e8FAf4A5655469182A49a505055B71C17604'

Use a .dev.vars file with ANKR_API_KEY=... so the Worker can call Ankr locally.

POST request to Worker (JSON body params)

curl --request POST \
  --url 'http://127.0.0.1:8787/' \
  --header 'accept: application/json' \
  --header 'content-type: application/json' \
  --data '{
  "method": "ankr_getAccountBalance",
  "id": 1,
  "forwardMethod": "POST",
  "blockchain": ["eth"],
  "nativeFirst": true,
  "onlyWhitelisted": true,
  "pageSize": 10,
  "pageToken": "1",
  "walletAddress": "0xE936e8FAf4A5655469182A49a505055B71C17604"
}'

Direct call to Ankr (same JSON-RPC the Worker sends)

Without the proxy, the equivalent request is a POST to https://rpc.ankr.com/multichain/<your-api-key>:

curl --request POST \
  --url 'https://rpc.ankr.com/multichain/<your-api-key>' \
  --header 'accept: application/json' \
  --header 'content-type: application/json' \
  --data '{
  "jsonrpc": "2.0",
  "method": "ankr_getAccountBalance",
  "params": {
    "blockchain": ["eth"],
    "nativeFirst": true,
    "onlyWhitelisted": true,
    "pageSize": 10,
    "pageToken": "1",
    "walletAddress": "0xE936e8FAf4A5655469182A49a505055B71C17604"
  },
  "id": 1
}'

The GET examples above build this same JSON-RPC payload (default forwardMethod=POST).

Local development

npm install
npx wrangler login
npx wrangler secret put ANKR_API_KEY
npm run dev

wrangler login opens a browser flow so Wrangler can deploy and manage secrets on your account. For CI, use an API token instead (below).

Cloudflare API token and account ID

Create CLOUDFLARE_API_TOKEN

1. Cloudflare dashboard → My Profile → API Tokens → Create Token.
2. Use a template like Edit Cloudflare Workers, or create a Custom token with at least:
   • Account → Workers Scripts → Edit

That is enough to deploy this Worker to *.workers.dev.

You may not see Account → Workers Routes in the token builder. That is common. Routes are only needed if you attach the Worker to a custom hostname or zone route. For the default workers.dev URL, you do not need a routes permission.

If you do use custom domains or zone routes, add Zone-scoped permission (scoped to that zone), for example:

• Zone → Workers Routes → Edit

Keep the token scoped to the correct Account (and Zone, if you add zone permissions).

Get CLOUDFLARE_ACCOUNT_ID

In the Cloudflare dashboard, open the target account and copy Account ID from the overview sidebar.

GitHub Actions secrets

Add these under the repo → Settings → Secrets and variables → Actions → New repository secret:

Secret	Description
ANKR_API_KEY	Ankr API key (path segment after /multichain/)
CLOUDFLARE_API_TOKEN	API token with Workers Scripts: Edit (see above)
CLOUDFLARE_ACCOUNT_ID	Your Cloudflare account ID

The workflow (.github/workflows/deploy.yml) sets ANKR_API_KEY on the Worker via wrangler secret put, then runs wrangler deploy.

If deploy fails with auth errors

• Token is scoped to the wrong account.
• Token is missing Workers Scripts: Edit.
• CLOUDFLARE_ACCOUNT_ID does not match the account the token can access.