Respondable is already a word. Found in formal as well as informal, technical as well as non-technical writing.
1 ruby-doc.org Class: Respondable
2 Lan Shi: Respondable risk and incentives for CEOs: The role of information-collection and decision-making
This paper examines the incentive provision when the agent can respond to risk by exerting effort to collect information about the underlying state and making corresponding decisions. Such effort is shown to be more valuable in a riskier environment and incentives can increase with “respondable” risk. The relation between incentives and risk is more positive when the agent's effort is more effective in collecting information or in acting upon it. Using data on chief executive officers (CEOs), I find that incentives for CEOs increase with industry-wide risk, a measure of respondable risk. The positive relation diminishes when the CEO is less able to collect information or is less effective in acting upon it.
3 RealWired! You Need to be “Respondable”
It’s not a typo. The word I’m using and intended to use is “respondable”. I’m using it as an adjective and I suggest you adopt it that way too. Here’s what I’m suggesting. If you are communicating, particularly in the world of social media, you have a responsibility to make what you put out there respondable. Hint: If you are going to adopt what I suggest, you better add “respondable” to your processor’s dictionary, because I assure you it’s not there and that alone will drive you nuts.
4 V-REP Static/non-static, respondable/ non-respondable shape behaviors and interactions
During dynamic simulation, static shapes will not be influenced (i.e. their position relative to their parent object is fixed), whereas non-static shapes will be directly influenced by gravity or other constraints (e.g. dynamically enabled joints, see hereafter). Respondable shapes influence each other during dynamic collision (i.e. they produce a mutual collision reaction, they will bounce off each other). Following figure illustrates the static/non-static, respondable/non-respondable behaviors ...

5 quora.com When will Google+ allow me to receive respondable text message updates like Facebook notifications?
Facebook mobile forwards me status updates from specific friends, and if I reply to that text, it will post my response on their status.
6 Quiplip: Respondable Holiday Card Set
Quiplip’s greeting cards deliver a diverse range of sentiments with a dinosauric dose of snark to wash ‘em down. [...] recipients will be absolutely overflowing with... you'll find out which emotion when they send the return postcard back to you!