Moralis Streams API

CRITICAL: Read Rule Files Before Implementing

The #1 cause of bugs is using wrong HTTP methods or stream configurations.

For EVERY endpoint:

1. Read rules/{EndpointName}.md
2. Check HTTP method (PUT for create, POST for update, DELETE for delete)
3. Verify stream ID format (UUID, not hex)
4. Use hex chain IDs (0x1, 0x89), not names (eth, polygon)

Reading Order:

1. This SKILL.md (core patterns)
2. Endpoint rule file in rules/
3. Pattern references in references/ (for edge cases only)

Setup

API Key (optional)

Never ask the user to paste their API key into the chat. Instead:

1. Check if MORALIS_API_KEY is set in the environment (try running [ -n "$MORALIS_API_KEY" ] && echo "API key is set" || echo "API key is NOT set").
2. If not set, offer to create the .env file with an empty placeholder: MORALIS_API_KEY=
3. Tell the user to open the .env file and paste their key there themselves.
4. Let them know: without the key, you won't be able to test or call the Moralis API on their behalf.

If they don't have a key yet, point them to admin.moralis.com/register (free, no credit card).

Environment Variable Discovery

The .env file location depends on how skills are installed:

Create the .env file in the project root (same directory the user runs Claude Code from). Make sure .env is in .gitignore.

Verify Your Key

curl "https://api.moralis-streams.com/streams/evm?limit=10" \
  -H "X-API-Key: $MORALIS_API_KEY"

Base URL

https://api.moralis-streams.com

Important: Different from Data API (deep-index.moralis.io).

Authentication

All requests require: X-API-Key: $MORALIS_API_KEY

HTTP Methods (CRITICAL)

Common mistake: Using POST to create streams. Use PUT instead.

Stream Types

Quick Reference: Most Common Patterns

Stream ID Format (ALWAYS UUID)

// WRONG - Hex format
"0x1234567890abcdef"

// CORRECT - UUID format
"a1b2c3d4-e5f6-7890-abcd-ef1234567890"

Chain IDs (ALWAYS hex)

"0x1"     // Ethereum
"0x89"    // Polygon
"0x38"    // BSC
"0xa4b1"  // Arbitrum
"0xa"     // Optimism
"0x2105"  // Base

Event Signatures (topic0)

"Transfer(address,address,uint256)"   // ERC20/NFT Transfer
"Approval(address,address,uint256)"   // ERC20 Approval

Status Values (lowercase only)

"active"      // CORRECT - normal operating state
"paused"      // CORRECT - manually paused
"error"       // CORRECT - auto-set when webhook success rate <70%
"terminated"  // CORRECT - unrecoverable, after 24h in error
"ACTIVE"      // WRONG

Common Pitfalls (Top 5)

1. Using POST to create streams - Use PUT instead
2. Wrong base URL - Use api.moralis-streams.com, NOT deep-index.moralis.io
3. Hex stream ID - Must be UUID format, not hex
4. String chain names - Use hex (0x1), not names (eth)
5. Uppercase status - Use lowercase ("active", "paused")
6. Not returning 200 on test webhook - Stream won't start unless your endpoint returns 2xx on the test webhook sent during create/update

See references/CommonPitfalls.md for complete reference.

Triggers (Read-Only Contract Calls)

Enrich webhook data with on-chain reads (e.g., balanceOf). Triggers execute view/pure functions and attach results to webhook events. Supports dynamic selectors ($contract, $from, $to). See references/Triggers.md for complete reference with examples.

Native Balances in Webhooks

Configure getNativeBalances to include native token balances (ETH, BNB, etc.) in webhook payloads. Requires Business plan+. See references/UsefulStreamOptions.md for configuration details.

Delivery and Error Handling

• Two webhooks per event: Unconfirmed (confirmed: false) + Confirmed (confirmed: true). Idempotent handlers required.
• Streams auto-terminate after 24 hours in error state (webhook success rate <70%). This is unrecoverable — you must create a new stream.
• Test webhook: Sent on every create/update. Must return 200 or stream won't start.

See references/DeliveryGuarantees.md and references/ErrorHandling.md.

Webhook Security

Webhooks are signed with your streams secret (different from API key).

• Header: x-signature
• Algorithm: sha3(JSON.stringify(body) + secret)

const verifySignature = (req, secret) => {
  const provided = req.headers["x-signature"];
  const generated = web3.utils.sha3(JSON.stringify(req.body) + secret);
  if (generated !== provided) throw new Error("Invalid Signature");
};

See references/WebhookSecurity.md for complete examples.

Testing Endpoints

WEBHOOK_URL="https://your-server.com/webhook"

# List streams (requires limit)
curl "https://api.moralis-streams.com/streams/evm?limit=100" \
  -H "X-API-Key: $MORALIS_API_KEY"

# Create stream (PUT, not POST)
curl -X PUT "https://api.moralis-streams.com/streams/evm" \
  -H "X-API-Key: $MORALIS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "webhookUrl": "'${WEBHOOK_URL}'",
    "description": "Test stream",
    "tag": "test",
    "topic0": ["Transfer(address,address,uint256)"],
    "allAddresses": false,
    "chainIds": ["0x1"]
  }'

# Pause stream (POST to status)
curl -X POST "https://api.moralis-streams.com/streams/evm/<stream_id>/status" \
  -H "X-API-Key: $MORALIS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"status": "paused"}'

Quick Troubleshooting

Endpoint Catalog

Complete list of all 20 Streams API endpoints organized by category.

Stream Management

Create, update, delete, and manage streams.

Status & Settings

Pause/resume streams and configure settings.

History & Analytics

Stream history, replay, statistics, logs, and block data.

Listen to All Addresses

Set allAddresses: true with a topic0 and abi to monitor an event across every contract on a chain (e.g., all ERC20 transfers network-wide). Requires higher-tier plans. See references/ListenToAllAddresses.md for complete examples, ABI templates, and gotchas.

Example: Create ERC20 Transfer Monitor

curl -X PUT "https://api.moralis-streams.com/streams/evm" \
  -H "X-API-Key: $MORALIS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "webhookUrl": "https://your-server.com/webhook",
    "description": "Monitor ERC20 transfers",
    "tag": "erc20-monitor",
    "topic0": ["Transfer(address,address,uint256)"],
    "allAddresses": true,
    "chainIds": ["0x1", "0x89"],
    "advancedOptions": [{
      "topic0": "Transfer(address,address,uint256)",
      "includeNativeHash": true
    }]
  }'

Pagination

List endpoints use cursor-based pagination:

# First page
curl "...?limit=100" -H "X-API-Key: $KEY"

# Next page
curl "...?limit=100&cursor=<cursor>" -H "X-API-Key: $KEY"

Supported Chains

All major EVM chains: Ethereum (0x1), Polygon (0x89), BSC (0x38), Arbitrum (0xa4b1), Optimism (0xa), Base (0x2105), Avalanche (0xa86a), and more.

See references/StreamConfiguration.md for complete chain ID list.

Reference Documentation

• references/CommonPitfalls.md - Complete pitfalls reference
• references/DeliveryGuarantees.md - At-least-once delivery, dual webhooks, confirmation blocks, test webhooks
• references/ErrorHandling.md - Retry schedule, error/terminated states, rate limits, re-org handling
• references/FAQ.md - Streams API frequently asked questions
• references/FilterStreams.md - Webhook data filtering to reduce noise
• references/ListenToAllAddresses.md - Monitor events across all contracts on a chain
• references/MonitorMultipleAddresses.md - Multi-address monitoring patterns
• references/ReplayFailedWebhooks.md - Replay failed webhook guide
• references/StreamConfiguration.md - Stream config reference
• references/Triggers.md - Read-only contract call enrichment (balanceOf, etc.)
• references/Tutorials.md - Real-world examples and tutorials
• references/UsefulStreamOptions.md - Advanced stream configuration options
• references/WebhookResponseBody.md - Webhook payload structure
• references/WebhookSecurity.md - Signature verification

See Also

• Endpoint rules: rules/*.md files
• Data API: @moralis-data-api for querying blockchain state