user115309: I am trying to incorporate bitcoin in one of the applications and want to integrate the REST API which exposes all the public information.
I tried using https://chain.api.btc.com/v3/block/3 but upon multiple requests, it starts to error out with message "Do not abuse the api".
Kindly provide the reference to API which I can use
Note: Tried https://testnet.blockexplorer.com/api as well but doesnt work. Even the link on https://github.com/blockchain/api-v1-client-python#request-limits-and-api-keys leads to error page on web

user100690: If you plan to using any API extensively I suggest installing bitcoin core and using RPC provided.

user117651: I don't know if there  is an unlimited and free service as you looking for,  but you can easily setup your own Bitcoin node and make all the calls you want, in addition it helps the Bitcoin network to be healthier and safer.
https://bitcoin.org/en/full-node
https://github.com/bitcoin/bitcoin/blob/master/doc/REST-interface.md

115309: <p>I am trying to incorporate bitcoin in one of the applications and want to integrate the REST API which exposes all the public information.</p>
<p>I tried using <code>https://chain.api.btc.com/v3/block/3</code> but upon multiple requests, it starts to error out with message &quot;Do not abuse the api&quot;.</p>
<p>Kindly provide the reference to API which I can use</p>
<p>Note: Tried <code>https://testnet.blockexplorer.com/api</code> as well but doesnt work. Even the link on <code>https://github.com/blockchain/api-v1-client-python#request-limits-and-api-keys</code> leads to error page on web</p>
 100690: <p>If you plan to using any API extensively I suggest installing <a href="https://bitcoin.org/en/bitcoin-core/" rel="nofollow noreferrer">bitcoin core</a> and using <a href="https://bitcoincore.org/en/doc/0.21.0/" rel="nofollow noreferrer">RPC</a> provided.</p>
 117651: <p>I don't know if there  is an unlimited and free service as you looking for,  but you can easily setup your own Bitcoin node and make all the calls you want, in addition it helps the Bitcoin network to be healthier and safer.</p>
<p><a href="https://bitcoin.org/en/full-node" rel="nofollow noreferrer">https://bitcoin.org/en/full-node</a><br>
<a href="https://github.com/bitcoin/bitcoin/blob/master/doc/REST-interface.md" rel="nofollow noreferrer">https://github.com/bitcoin/bitcoin/blob/master/doc/REST-interface.md</a></p>
