Hey Guggero, I started trying out some of the endpoints tonight. I may have found some quirks that can help with the process.

POST /v2/wallet/address/next
Cannot send empty string data in POST body
My code has an empty string in the POST body, and that has worked so far for v1 endpoints, though I'm not sure if its really a good or bad thing. Doing it for this endpoint gave Go unmarshalling errors.

This next endpoint is the big one everyone is probably eager to use
POST /v2/router/send
It seems like it is returning data for each attempt. It is returning multiple dictionaries with {"result":} keys, when I think it should only return one. At its current state, I cannot do json.loads({}).

I was splitting along the newline to watch as it tried the attempts:
for i in range(0,19): len(json.loads(r.text.split('\n')[i])['result']['htlcs'])

I also tried out: GET /v2/router/htlcevents
And it seemed to work, but you saidwebsockets weren't working yet, and think these streaming ones will work better with websockets instead of the python "for loop" syntax, so I might play around with that more later.

POST /v2/router/send return data:

'{"result":{"payment_hash":"5eb8b650f4708209bf39e14f09d05690991dc9ad949f60d4b8df1bad326819fe","value":"1000000","creation_date":"1591321010","fee":"0","payment_preimage":"0000000000000000000000000000000000000000000000000000000000000000","value_sat":"1000000","value_msat":"1000000000","payment_request":"lnbc10m1p0dngdfpp5t6utv585wzpqn0eeu98sn5zkjzv3mjddjj0kp49cmud66vngr8lqdq2w3jhxapqxgcqzpgsp52tnfp5dzv7w50pg42dd0lz6tgp5fpdn3c3ythpverj0hw2zkc4ks9qy9qsqv7d3qwkpz32dlhqrpf5nsv9f76xfd8yz6m5fw8lakc3z9f8l03usxcvzgyyh753elyds7ckdrw2rdc9ue46p4aevhsh9a9z5u78ufwcqe5myaz","status":"IN_FLIGHT","fee_sat":"0","fee_msat":"0","creation_time_ns":"1591321010843009472","htlcs":[],"payment_index":"3856","failure_reason":"FAILURE_REASON_NONE"}}\n{"result":{"payment_hash":"5eb8b650f4708209bf39e14f09d05690991dc9ad949f60d4b8df1bad326819fe","value":"1000000","creation_date":"1591321010","fee":"0","payment_preimage":"0000000000000000000000000000000000000000000000000000000000000000","value_sat":"1000000","value_msat":"1000000000","payment_request":"lnbc10m1p0dngdfpp5t6utv585wzpqn0eeu98sn5zkjzv3mjddjj0kp49cmud66vngr8lqdq2w3jhxapqxgcqzpgsp52tnfp5dzv7w50pg42dd0lz6tgp5fpdn3c3ythpverj0hw2zkc4ks9qy9qsqv7d3qwkpz32dlhqrpf5nsv9f76xfd8yz6m5fw8lakc3z9f8l03usxcvzgyyh753elyds7ckdrw2rdc9ue46p4aevhsh9a9z5u78ufwcqe5myaz","status":"IN_FLIGHT","fee_sat":"0","fee_msat":"0","creation_time_ns":"1591321010843009472","htlcs":[{"status":"IN_FLIGHT","route":{"total_time_lock":633190,"total_fees":"2","total_amt":"1000002","hops":[{"chan_id":"694210751119753216","chan_capacity":"4388592","amt_to_forward":"1000000","fee":"2","expiry":633150,"amt_to_forward_msat":"1000000000","fee_msat":"2000","pub_key":"0292052c3ab594f7b5e997099f66e8ed51b4342126dcb5c3caa76b38adb725dcdb","tlv_payload":true,"mpp_record":null,"custom_records":{}},{"chan_id":"694210751119753216","chan_capacity":"4388592","amt_to_forward":"1000000","fee":"0","expiry":633150,"amt_to_forward_msat":"1000000000","fee_msat":"0","pub_key":"0360a41eb8c3fe09782ef6c984acbb003b0e1ebc4fe10ae01bab0e80d76618c8f4","tlv_payload":true,"mpp_record":{"payment_addr":"UuaQ0aJnnUeFFVNa/4tLQGiQtnHESLuFmRyfdyhWxW0=","total_amt_msat":"1000000000"},"custom_records":{}}],"total_fees_msat":"2000","total_amt_msat":"1000002000"},"attempt_time_ns":"1591321010865159252","resolve_time_ns":"0","failure":null,"preimage":null}],"payment_index":"3856","failure_reason":"FAILURE_REASON_NONE"}}\n{"result":{"payment_hash":"5eb8b650f4708209bf39e14f09d05690991dc9ad949f60d4b8df1bad326819fe","value":"1000000","creation_date":"1591321010","fee":"2","payment_preimage":"7f2fc0cca0ecc486929e8b9cbf9659902748d483327c95d373956f3f556dcd05","value_sat":"1000000","value_msat":"1000000000","payment_request":"lnbc10m1p0dngdfpp5t6utv585wzpqn0eeu98sn5zkjzv3mjddjj0kp49cmud66vngr8lqdq2w3jhxapqxgcqzpgsp52tnfp5dzv7w50pg42dd0lz6tgp5fpdn3c3ythpverj0hw2zkc4ks9qy9qsqv7d3qwkpz32dlhqrpf5nsv9f76xfd8yz6m5fw8lakc3z9f8l03usxcvzgyyh753elyds7ckdrw2rdc9ue46p4aevhsh9a9z5u78ufwcqe5myaz","status":"SUCCEEDED","fee_sat":"2","fee_msat":"2000","creation_time_ns":"1591321010843009472","htlcs":[{"status":"SUCCEEDED","route":{"total_time_lock":633190,"total_fees":"2","total_amt":"1000002","hops":[{"chan_id":"694210751119753216","chan_capacity":"4388592","amt_to_forward":"1000000","fee":"2","expiry":633150,"amt_to_forward_msat":"1000000000","fee_msat":"2000","pub_key":"0292052c3ab594f7b5e997099f66e8ed51b4342126dcb5c3caa76b38adb725dcdb","tlv_payload":true,"mpp_record":null,"custom_records":{}},{"chan_id":"694210751119753216","chan_capacity":"4388592","amt_to_forward":"1000000","fee":"0","expiry":633150,"amt_to_forward_msat":"1000000000","fee_msat":"0","pub_key":"0360a41eb8c3fe09782ef6c984acbb003b0e1ebc4fe10ae01bab0e80d76618c8f4","tlv_payload":true,"mpp_record":{"payment_addr":"UuaQ0aJnnUeFFVNa/4tLQGiQtnHESLuFmRyfdyhWxW0=","total_amt_msat":"1000000000"},"custom_records":{}}],"total_fees_msat":"2000","total_amt_msat":"1000002000"},"attempt_time_ns":"1591321010865159252","resolve_time_ns":"1591321011235110235","failure":null,"preimage":"fy/AzKDsxIaSnoucv5ZZkCdI1IMyfJXTc5VvP1VtzQU="}],"payment_index":"3856","failure_reason":"FAILURE_REASON_NONE"}}\n'

@sako0938 thank you very much for testing!

Cannot send empty string data in POST body

I don't think sending an empty POST worked before that PR. Or maybe it changed because of the library update. But in any case, a POST body always has to be set. If there's no content to send, just send a "{}".

It seems like it is returning data for each attempt. It is returning multiple dictionaries with {"result":} keys, when I think it should only return one. At its current state, I cannot do json.loads({}).

That's exactly why WebSockets are needed, because there are multiple messages being returned that are valid JSON each on its own. Adding WebSocket support is the whole point of this PR (while adding the REST endpoints was done in PR 2/3). So please test again with a WS library (code examples can be found in the preview of the API doc: https://www.guggero.org/lightning-api/#v2-router-send)

but you saidwebsockets weren't working yet

Was I referring to this PR specifically? Maybe there was a misunderstanding. They should work now :)