Check state and condition of Tor support among currently supported API providers

I assume that none of the API providers block Tor exit nodes ("relay" type) and consequently focus only on Tor-native or self-hosted approaches.

Toshi (currently recommended for reads)

Native: no evidence
Self-hosted: yes, source available at https://github.com/coinbase/toshi
Relay: should be possible, but see NOTES
Blockr.io (currently recommended for writes)
Native: no evidence
Self-hosted: no
Relay: yes, existing example at https://github.com/tailsjoin/tailsjoin/blob/master/tailsjoin.sh#L19, but see NOTES
Blockchain.info
Native: yes, https://blockchainbdgpzk.onion
Self-hosted: no
Relay: yes, but see NOTES
Insight
Native: no
Self-hosted: yes, source available at https://github.com/bitpay/insight-api
Relay: should be possible, but see NOTES
SoChain
Native: no
Self-hosted: no
Relay: should be possible, but see NOTES
Bitcoin Core
[not yet supported; contributors are welcome to help out with this]

NOTES

Users of these APIs have alleged (see https://bitcointalk.org/index.php?topic=852545.0) hijacking attacks when accessing some of these APIs via Tor exit nodes, so it appears that self-hosted and native approach are safer choices.