Bitcoin Core REST API

Bitcoin Core REST Interface

A read-only HTTP API exposed when rest=1 is set. No authentication, no batching needed, runs on the same port as RPC (8332).

Enable

rest=1
rpcbind=127.0.0.1:8332

Recommended: bind only to localhost (or use a TLS reverse proxy for public access).

Endpoints

Format: /rest/<resource>/<id>.<format> where format is json, bin, or hex.

Examples

# Get block hash for height 800000
curl -s 'http://127.0.0.1:8332/rest/blockhashbyheight/800000.json' | jq

# Get the block
curl -s 'http://127.0.0.1:8332/rest/block/<hash>.json' | jq '.tx[:5]'

# Get a tx (requires txindex if it's old)
curl -s 'http://127.0.0.1:8332/rest/tx/<txid>.json' | jq

# Check UTXO existence (multiple at once, with mempool consideration)
curl -s 'http://127.0.0.1:8332/rest/getutxos/checkmempool/<txid>-0/<txid2>-1.json' | jq

When to prefer REST over RPC

REST is better for:

• High-throughput read services where RPC auth overhead matters.
• Public read APIs (with proxy).
• Tools that prefer raw HTTP / binary fetches.

RPC is better for:

• Anything writing state (broadcast, wallet ops).
• Atomic batch reads.
• Auth-required environments.

Limits

• getutxos checks: max 15 UTXOs per call.
• headers endpoint: max 2000 headers per call.
• No built-in pagination for mempool/contents.

Public exposure considerations

Bitcoin Core REST has no built-in TLS, no rate limiting, no auth. For public exposure:

• TLS reverse proxy (nginx / Caddy).
• Rate limit (nginx limit_req_zone).
• Cache at the proxy layer (block data is immutable; tx data is immutable once mined).

Esplora / mempool.space build on top of Core's REST + custom indexers.

Common bugs

• 404 on /rest/tx/<txid> for old tx → need txindex=1.
• 503 during sync → REST returns errors during IBD. Check /rest/chaininfo.json first.
• Querying with a 0x-prefixed txid → no, just hex string.
• Mistaking .bin for hex string — .bin is raw binary bytes.

See also

• rpc/SKILL.md
• zmq/SKILL.md
• ../../infrastructure/esplora/SKILL.md