diff --git a/index.js b/index.js
index f63cd7a..077a42c 100644
--- a/index.js
+++ b/index.js
@@ -4,14 +4,9 @@
 
 var PromiseA = require('bluebird');
 var leCore = require('letiny-core');
-var utils = require('./lib/common');
-var merge = require('./lib/common').merge;
-var tplCopy = require('./lib/common').tplCopy;
 
 var LE = module.exports;
 
-LE.merge = require('./lib/common').merge;
-
 LE.defaults = {
   server: leCore.productionServerUrl
 , stagingServer: leCore.stagingServerUrl
@@ -28,12 +23,11 @@ Object.keys(LE.defaults).forEach(function (key) {
   LE[key] = LE.defaults[key];
 });
 
-                    // backend, defaults, handlers
 LE.create = function (defaults, handlers, backend) {
-  var Backend = require('./lib/core');
-  if (!backend) { backend = require('./lib/pycompat').create(defaults); }
+  var Core = require('./lib/core');
+  var core;
+  if (!backend) { backend = require('./lib/pycompat'); }
   if (!handlers) { handlers = {}; }
-  if (!handlers.lifetime) { handlers.lifetime = 90 * 24 * 60 * 60 * 1000; }
   if (!handlers.renewWithin) { handlers.renewWithin = 3 * 24 * 60 * 60 * 1000; }
   if (!handlers.memorizeFor) { handlers.memorizeFor = 1 * 24 * 60 * 60 * 1000; }
   if (!handlers.sniRegisterCallback) {
@@ -42,188 +36,45 @@ LE.create = function (defaults, handlers, backend) {
       cb(null, null);
     };
   }
-  if (!handlers.getChallenge) {
-    if (!defaults.manual && !defaults.webrootPath) {
-      // GET /.well-known/acme-challenge/{{challengeKey}} should return {{tokenValue}}
-      throw new Error("handlers.getChallenge or defaults.webrootPath must be set");
-    }
-    handlers.getChallenge = function (hostname, key, done) {
-      // TODO associate by hostname?
-      // hmm... I don't think there's a direct way to associate this with
-      // the request it came from... it's kinda stateless in that way
-      // but realistically there only needs to be one handler and one
-      // "directory" for this. It's not that big of a deal.
-      var defaultos = LE.merge({}, defaults);
-      var getChallenge = require('./lib/default-handlers').getChallenge;
-      var copy = merge({ domains: [hostname] }, defaults);
 
-      tplCopy(copy);
-      defaultos.domains = [hostname];
-
-      if (3 === getChallenge.length) {
-        console.warn('[WARNING] Deprecated use. Define getChallenge as function (opts, domain, key, cb) { }');
-        getChallenge(defaultos, key, done);
-      }
-      else if (4 === getChallenge.length) {
-        getChallenge(defaultos, hostname, key, done);
-      }
-      else {
-        done(new Error("handlers.getChallenge [1] receives the wrong number of arguments"));
-      }
-    };
+  if (backend.create) {
+    backend = backend.create(defaults);
   }
-  if (!handlers.setChallenge) {
-    if (!defaults.webrootPath) {
-      // GET /.well-known/acme-challenge/{{challengeKey}} should return {{tokenValue}}
-      throw new Error("handlers.setChallenge or defaults.webrootPath must be set");
-    }
-    handlers.setChallenge = require('./lib/default-handlers').setChallenge;
-  }
-  if (!handlers.removeChallenge) {
-    if (!defaults.webrootPath) {
-      // GET /.well-known/acme-challenge/{{challengeKey}} should return {{tokenValue}}
-      throw new Error("handlers.removeChallenge or defaults.webrootPath must be set");
-    }
-    handlers.removeChallenge = require('./lib/default-handlers').removeChallenge;
-  }
-  if (!handlers.agreeToTerms) {
-    if (defaults.agreeTos) {
-      console.warn("[WARN] Agreeing to terms by default is risky business...");
-    }
-    handlers.agreeToTerms = require('./lib/default-handlers').agreeToTerms;
-  }
-
-  backend = Backend.create(defaults, handlers);
   backend = PromiseA.promisifyAll(backend);
+  core = Core.create(defaults, handlers, backend);
 
-  //var attempts = {};  // should exist in master process only
-  var le;
-
-  // TODO check certs on initial load
-  // TODO expect that certs expire every 90 days
-  // TODO check certs with setInterval?
-  //options.cacheContextsFor = options.cacheContextsFor || (1 * 60 * 60 * 1000);
-
-  le = {
+  var le = {
     backend: backend
-  , pyToJson: function (pyobj) {
-      if (!pyobj) {
-        return null;
-      }
-
-      var jsobj = {};
-      Object.keys(pyobj).forEach(function (key) {
-        jsobj[key] = pyobj[key];
-      });
-      jsobj.__lines = undefined;
-      jsobj.__keys = undefined;
-
-      return jsobj;
-    }
-  , register: function (args, cb) {
-      if (defaults.debug || args.debug) {
-        console.log('[LE] register');
-      }
-      if (!Array.isArray(args.domains)) {
-        cb(new Error('args.domains should be an array of domains'));
-        return;
-      }
-
-      var copy = LE.merge(args, defaults);
-      var err;
-
-      if (!utils.isValidDomain(args.domains[0])) {
-        err = new Error("invalid domain name: '" + args.domains + "'");
-        err.code = "INVALID_DOMAIN";
-        cb(err);
-        return;
-      }
-
-      if ((!args.domains.length && args.domains.every(le.isValidDomain))) {
-        // NOTE: this library can't assume to handle the http loopback
-        // (or dns-01 validation may be used)
-        // so we do not check dns records or attempt a loopback here
-        cb(new Error("node-letsencrypt: invalid hostnames: " + args.domains.join(',')));
-        return;
-      }
-
-      if (defaults.debug || args.debug) {
-        console.log("[NLE]: begin registration");
-      }
-
-      return backend.registerAsync(copy).then(function (pems) {
-        if (defaults.debug || args.debug) {
-          console.log("[NLE]: end registration");
-        }
+  , core: core
+    // register
+  , create: function (args, cb) {
+      return core.registerAsync(args).then(function (pems) {
         cb(null, pems);
-        //return le.fetch(args, cb);
       }, cb);
     }
-  , fetch: function (args, cb) {
-      if (defaults.debug || args.debug) {
-        console.log('[LE] fetch');
-      }
-
-      // TODO figure out what TPLs are needed
-      var copy = merge(args, defaults);
-      tplCopy(copy);
-
-      return backend.fetchAsync(args).then(function (certInfo) {
-        if (args.debug) {
-          console.log('[LE] raw fetch certs', certInfo && Object.keys(certInfo));
-        }
-        if (!certInfo) { cb(null, null); return; }
-
-        // key, cert, issuedAt, lifetime, expiresAt
-        if (!certInfo.expiresAt) {
-          certInfo.expiresAt = certInfo.issuedAt + (certInfo.lifetime || handlers.lifetime);
-        }
-        if (!certInfo.lifetime) {
-          certInfo.lifetime = (certInfo.lifetime || handlers.lifetime);
-        }
-        // a pretty good hard buffer
-        certInfo.expiresAt -= (1 * 24 * 60 * 60 * 100);
-
+    // fetch
+  , domain: function (args, cb) {
+      // TODO must return email, domains, tos, pems
+      return core.fetchAsync(args).then(function (certInfo) {
         cb(null, certInfo);
       }, cb);
     }
-  , getConfig: function (args, cb) {
-      if (defaults.debug || args.debug) {
-        console.log('[LE] getConfig');
-      }
-      backend.getConfigAsync(args).then(function (pyobj) {
-        cb(null, le.pyToJson(pyobj));
-      }, function (err) {
-        console.error("[letsencrypt/index.js] getConfig");
-        console.error(err.stack);
-        return cb(null, []);
-      });
+  , domains: function (args, cb) {
+      // TODO show all domains or limit by account
+      throw new Error('not implemented');
     }
-  , getConfigs: function (args, cb) {
-      if (defaults.debug || args.debug) {
-        console.log('[LE] getConfigs');
-      }
-      backend.getConfigsAsync(args).then(function (configs) {
-        cb(null, configs.map(le.pyToJson));
-      }, function (err) {
-        if ('ENOENT' === err.code) {
-          cb(null, []);
-        } else {
-          console.error("[letsencrypt/index.js] getConfigs");
-          console.error(err.stack);
-          cb(err);
-        }
-      });
+  , accounts: function (args, cb) {
+      // TODO show all accounts or limit by domain
+      throw new Error('not implemented');
     }
-  , setConfig: function (args, cb) {
-      if (defaults.debug || args.debug) {
-        console.log('[LE] setConfig');
-      }
-      backend.configureAsync(args).then(function (pyobj) {
-        cb(null, le.pyToJson(pyobj));
-      });
+  , account: function (args, cb) {
+      // TODO return one account
+      throw new Error('not implemented');
     }
   };
 
+  // exists
+  // get
+
   return le;
 };
diff --git a/lib/common.js b/lib/common.js
index 9af37e3..e00919f 100644
--- a/lib/common.js
+++ b/lib/common.js
@@ -1,9 +1,6 @@
 'use strict';
 
-var fs = require('fs');
 var path = require('path');
-var PromiseA = require('bluebird');
-
 var homeRe = new RegExp("^~(\\/|\\\|\\" + path.sep + ")");
 var re = /^[a-zA-Z0-9\.\-]+$/;
 var punycode = require('punycode');
@@ -22,16 +19,6 @@ module.exports.isValidDomain = function (domain) {
   return '';
 };
 
-module.exports.tplConfigDir = function (configDir, defaults) {
-  var homedir = require('homedir')();
-  Object.keys(defaults).forEach(function (key) {
-    if ('string' === typeof defaults[key]) {
-      defaults[key] = defaults[key].replace(':config', configDir).replace(':conf', configDir);
-      defaults[key] = defaults[key].replace(homeRe, homedir + path.sep);
-    }
-  });
-};
-
 module.exports.merge = function (/*defaults, args*/) {
   var allDefaults = Array.prototype.slice.apply(arguments);
   var args = args.shift();
@@ -51,18 +38,6 @@ module.exports.merge = function (/*defaults, args*/) {
 };
 
 module.exports.tplCopy = function (copy) {
-  var url = require('url');
-  var acmeLocation = url.parse(copy.server);
-  var acmeHostpath = path.join(acmeLocation.hostname, acmeLocation.pathname);
-  copy.accountsDir = copy.accountsDir || path.join(copy.configDir, 'accounts', acmeHostpath);
-  // TODO move these defaults elsewhere?
-  //args.renewalDir = args.renewalDir || ':config/renewal/';
-  args.renewalPath = args.renewalPath || ':config/renewal/:hostname.conf';
-  // Note: the /directory is part of the server url and, as such, bleeds into the pathname
-  // So :config/accounts/:server/directory is *incorrect*, but the following *is* correct:
-  args.accountsDir = args.accountsDir || ':config/accounts/:server';
-  hargs.renewalDir = hargs.renewalDir || ':config/renewal/';
-  copy.renewalPath = copy.renewalPath || path.join(copy.configDir, 'renewal', copy.domains[0] + '.conf');
   var homedir = require('homedir')();
   var tpls = {
     hostname: (copy.domains || [])[0]
@@ -72,19 +47,20 @@ module.exports.tplCopy = function (copy) {
   };
 
   Object.keys(copy).forEach(function (key) {
-    if ('string' === typeof copy[key]) {
-      Object.keys(tpls).sort(function (a, b) {
-        return b.length - a.length;
-      }).forEach(function (tplname) {
-        if (!tpls[tplname]) {
-          // what can't be templated now may be templatable later
-          return;
-        }
-        copy[key] = copy[key].replace(':' + tplname, tpls[tplname]);
-        copy[key] = copy[key].replace(homeRe, homedir + path.sep);
-      });
+    if ('string' !== typeof copy[key]) {
+      return;
     }
-  });
 
-  //return copy;
+    copy[key] = copy[key].replace(homeRe, homedir + path.sep);
+
+    Object.keys(tpls).sort(function (a, b) {
+      return b.length - a.length;
+    }).forEach(function (tplname) {
+      if (!tpls[tplname]) {
+        // what can't be templated now may be templatable later
+        return;
+      }
+      copy[key] = copy[key].replace(':' + tplname, tpls[tplname]);
+    });
+  });
 };
diff --git a/lib/core.js b/lib/core.js
index 85f5001..93d73b6 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -4,6 +4,8 @@ var LE = require('../');
 var ipc = {}; // in-process cache
 
 module.exports.create = function (defaults, handlers, backend) {
+  var backendDefaults = backend.getDefaults && backend.getDefaults || backend.defaults || {};
+
   defaults.server = defaults.server || LE.liveServer;
   handlers.merge = require('./common').merge;
   handlers.tplCopy = require('./common').tplCopy;
@@ -13,9 +15,22 @@ module.exports.create = function (defaults, handlers, backend) {
   var LeCore = PromiseA.promisifyAll(require('letiny-core'));
   var crypto = require('crypto');
 
+  function attachCertInfo(results) {
+    var getCertInfo = require('./cert-info').getCertInfo;
+    // XXX Note: Parsing the certificate info comes at a great cost (~500kb)
+    var certInfo = getCertInfo(results.cert);
+
+    //results.issuedAt = arr[3].mtime.valueOf()
+    results.issuedAt = Date(certInfo.notBefore.value).valueOf(); // Date.now()
+    results.expiresAt = Date(certInfo.notAfter.value).valueOf();
+
+    return results;
+  }
+
   function createAccount(args, handlers) {
-    // arg.rsaBitLength args.rsaExponent
-    return RSA.generateKeypairAsync(args.rsaKeySize || 2048, 65537, { public: true, pem: true }).then(function (keypair) {
+    args.rsaKeySize = args.rsaKeySize || 2048;
+
+    return RSA.generateKeypairAsync(args.rsaKeySize, 65537, { public: true, pem: true }).then(function (keypair) {
 
       return LeCore.registerNewAccountAsync({
         email: args.email
@@ -71,6 +86,9 @@ module.exports.create = function (defaults, handlers, backend) {
   }
 
   function getCertificateAsync(args, defaults, handlers) {
+    args.rsaKeySize = args.rsaKeySize || 2048;
+    args.challengeType = args.challengeType || 'http-01';
+
     function log() {
       if (args.debug || defaults.debug) {
         console.log.apply(console, arguments);
@@ -106,6 +124,7 @@ module.exports.create = function (defaults, handlers, backend) {
       , accountKeypair: RSA.import(account.keypair)
       , domainKeypair: domainKeypair
       , domains: args.domains
+      , challengeType: args.challengeType
 
         //
         // IMPORTANT
@@ -116,39 +135,36 @@ module.exports.create = function (defaults, handlers, backend) {
         // (args is per-request, defaults is per instance)
         //
       , setChallenge: function (domain, key, value, done) {
-          var copy = handlers.merge({ domains: [domain] }, defaults);
+          var copy = handlers.merge({ domains: [domain] }, defaults, backendDefaults);
           handlers.tplCopy(copy);
 
-          args.domains = [domain];
-          //args.domains = args.domains || [domain];
-          if (4 === handlers.setChallenge.length) {
-            console.warn('[WARNING] deprecated use. Define setChallenge as function (opts, domain, key, val, cb) { }');
-            handlers.setChallenge(copy, key, value, done);
-          }
-          else if (5 === handlers.setChallenge.length) {
-            handlers.setChallenge(copy, domain, key, value, done);
-          }
-          else {
-            done(new Error("handlers.setChallenge receives the wrong number of arguments"));
+          //args.domains = [domain];
+          args.domains = args.domains || [domain];
+
+          if (5 !== handlers.setChallenge.length) {
+            done(new Error("handlers.setChallenge receives the wrong number of arguments."
+              + " You must define setChallenge as function (opts, domain, key, val, cb) { }"));
+            return;
           }
+
+          handlers.setChallenge(copy, domain, key, value, done);
         }
       , removeChallenge: function (domain, key, done) {
-          var copy = handlers.merge({ domains: [domain] }, defaults);
+          var copy = handlers.merge({ domains: [domain] }, defaults, backendDefaults);
           handlers.tplCopy(copy);
 
-          if (3 === handlers.removeChallenge.length) {
-            handlers.removeChallenge(copy, key, done);
-          }
-          else if (4 === handlers.removeChallenge.length) {
-            handlers.removeChallenge(copy, domain, key, done);
-          }
-          else {
-            done(new Error("handlers.removeChallenge receives the wrong number of arguments"));
+          if (4 !== handlers.removeChallenge.length) {
+            done(new Error("handlers.removeChallenge receives the wrong number of arguments."
+              + " You must define removeChallenge as function (opts, domain, key, cb) { }"));
+            return;
           }
+
+          handlers.removeChallenge(copy, domain, key, done);
         }
-      });
+      }).then(attachCertInfo);
     }).then(function (results) {
       // { cert, chain, fullchain, privkey }
+
       args.pems = results;
       return backend.setRegistration(args, defaults, handlers);
     });
@@ -160,7 +176,7 @@ module.exports.create = function (defaults, handlers, backend) {
       return getCertificateAsync(args, defaults, handlers);
     }
 
-    return backend.getRegistration(args).then(function (certs) {
+    return wrapped.fetchAsync(args).then(function (certs) {
       var halfLife = (certs.expiresAt - certs.issuedAt) / 2;
 
       if (!certs || (Date.now() - certs.issuedAt) > halfLife) {
@@ -196,27 +212,34 @@ module.exports.create = function (defaults, handlers, backend) {
           log('[le/core.js] use account');
 
           args.accountId = accountId;
-          return Accounts.getAccount(args, handlers);
+          return backend.getAccount(args, handlers);
         } else {
           log('[le/core.js] create account');
-          return Accounts.createAccount(args, handlers);
+          return createAccount(args, handlers);
         }
       });
-    }).then(function (account) {
-      /*
-      if (renewal.account !== account) {
-        // the account has become corrupt, re-register
-        return;
-      }
-      */
-      log('[le/core.js] created account');
-      return account;
     });
   }
 
   var wrapped = {
-   registerAsync: function (args) {
-      var copy = handlers.merge(args, defaults);
+    registerAsync: function (args) {
+      var utils = require('./lib/common');
+      var err;
+
+      if (!Array.isArray(args.domains)) {
+        return PromiseA.reject(new Error('args.domains should be an array of domains'));
+      }
+
+      if (!(args.domains.length && args.domains.every(utils.isValidDomain))) {
+        // NOTE: this library can't assume to handle the http loopback
+        // (or dns-01 validation may be used)
+        // so we do not check dns records or attempt a loopback here
+        err = new Error("invalid domain name(s): '" + args.domains + "'");
+        err.code = "INVALID_DOMAIN";
+        return PromiseA.reject(err);
+      }
+
+      var copy = handlers.merge(args, defaults, backendDefaults);
       handlers.tplCopy(copy);
 
       return getOrCreateAcmeAccount(copy, defaults, handlers).then(function (account) {
@@ -234,20 +257,23 @@ module.exports.create = function (defaults, handlers, backend) {
       });
     }
   , getOrCreateAccount: function (args) {
-      // TODO
-      keypair.privateKeyPem = RSA.exportPrivatePem(keypair);
-      keypair.publicKeyPem = RSA.exportPublicPem(keypair);
       return createAccount(args, handlers);
     }
   , configureAsync: function (hargs) {
-      var copy = merge(hargs, defaults);
-      tplCopy(copy);
+      var copy = handlers.merge(hargs, defaults, backendDefaults);
+      handlers.tplCopy(copy);
 
       return getOrCreateAcmeAccount(copy, defaults, handlers).then(function (account) {
         copy.account = account;
         return backend.getOrCreateRenewal(copy);
       });
     }
+  , fetchAsync: function (args) {
+      var copy = handlers.merge(args, defaults);
+      handlers.tplCopy(copy);
+
+      return backend.fetchAsync(copy).then(attachCertInfo);
+    }
   };
 
   return wrapped;