diff --git a/src/fetcher/gitlab.js b/src/fetcher/gitlab.js
index 437616f..0a3edd3 100644
--- a/src/fetcher/gitlab.js
+++ b/src/fetcher/gitlab.js
@@ -27,14 +27,7 @@ module.exports = async (data, opts) => {
 
   const fetchPromise = new Promise(async (resolve, reject) => {
     const urlUser = `https://${data.domain}/api/v4/users?username=${data.username}`
-    let resUser
-    try {
-      resUser = await req(urlUser, null, { Accept: 'application/json' })
-    } catch (e) {
-      resUser = await req(utils.generateProxyURL('web', urlUser, opts), null, {
-        Accept: 'application/json',
-      })
-    }
+    const resUser = await req(urlUser, null, { Accept: 'application/json' })
     const jsonUser = await resUser.json()
 
     const user = jsonUser.find((user) => user.username === match[2])
@@ -43,16 +36,7 @@ module.exports = async (data, opts) => {
     }
 
     const urlProject = `https://${data.domain}/api/v4/users/${user.id}/projects`
-    let resProject
-    try {
-      resProject = await req(urlProject, null, { Accept: 'application/json' })
-    } catch (e) {
-      resProject = await req(
-        utils.generateProxyURL('web', urlProject, opts),
-        null,
-        { Accept: 'application/json' }
-      )
-    }
+    const resProject = await req(urlProject, null, { Accept: 'application/json' })
     const jsonProject = await resProject.json()
 
     const project = jsonProject.find((proj) => proj.path === 'gitlab_proof')
diff --git a/src/fetcher/http.js b/src/fetcher/http.js
index 43c65d9..72db0e1 100644
--- a/src/fetcher/http.js
+++ b/src/fetcher/http.js
@@ -15,6 +15,7 @@ limitations under the License.
 */
 const bent = require('bent')
 const req = bent('GET')
+const E = require('../enums')
 
 module.exports = async (data, opts) => {
   let timeoutHandle
@@ -31,11 +32,11 @@ module.exports = async (data, opts) => {
       return
     }
 
-    switch (format) {
-      case 'json':
+    switch (data.format) {
+      case E.ProofFormat.JSON:
         req(data.url, null, {
           Accept: 'application/json',
-          'User-Agent': `doipjs/${require('../package.json').version}`,
+          'User-Agent': `doipjs/${require('../../package.json').version}`,
         })
           .then(async (res) => {
             return await res.json()
@@ -47,7 +48,7 @@ module.exports = async (data, opts) => {
             reject(e)
           })
         break
-      case 'text':
+      case E.ProofFormat.TEXT:
         req(data.url)
           .then(async (res) => {
             return await res.text()
diff --git a/src/fetcher/irc.js b/src/fetcher/irc.js
index 1fd4218..16eb640 100644
--- a/src/fetcher/irc.js
+++ b/src/fetcher/irc.js
@@ -25,6 +25,12 @@ module.exports = async (data, opts) => {
   })
 
   const fetchPromise = new Promise((resolve, reject) => {
+    try {
+      validator.isAscii(opts.claims.irc.nick)
+    } catch (err) {
+      throw new Error(`IRC fetcher was not set up properly (${err.message})`)
+    }
+
     try {
       const client = new irc.Client(data.domain, opts.nick, {
         port: 6697,
diff --git a/src/fetcher/matrix.js b/src/fetcher/matrix.js
index 00c84e2..0d6454c 100644
--- a/src/fetcher/matrix.js
+++ b/src/fetcher/matrix.js
@@ -15,6 +15,7 @@ limitations under the License.
 */
 const bent = require('bent')
 const bentReq = bent('GET')
+const validator = require('validator')
 
 module.exports = async (data, opts) => {
   let timeoutHandle
@@ -25,9 +26,15 @@ module.exports = async (data, opts) => {
     )
   })
 
-  const url = `https://${opts.instance}/_matrix/client/r0/rooms/${data.roomId}/event/${data.eventId}?access_token=${opts.accessToken}`
-
   const fetchPromise = new Promise((resolve, reject) => {
+    try {
+      validator.isFQDN(opts.claims.matrix.instance)
+      validator.isAscii(opts.claims.matrix.accessToken)
+    } catch (err) {
+      throw new Error(`Matrix fetcher was not set up properly (${err.message})`)
+    }
+
+    const url = `https://${opts.claims.matrix.instance}/_matrix/client/r0/rooms/${data.roomId}/event/${data.eventId}?access_token=${opts.claims.matrix.accessToken}`
     bentReq(url, null, {
       Accept: 'application/json',
     })
diff --git a/src/fetcher/twitter.js b/src/fetcher/twitter.js
index 23041a4..1fcbeb0 100644
--- a/src/fetcher/twitter.js
+++ b/src/fetcher/twitter.js
@@ -26,6 +26,12 @@ module.exports = async (data, opts) => {
   })
 
   const fetchPromise = new Promise((resolve, reject) => {
+    try {
+      validator.isAscii(opts.claims.twitter.bearerToken)
+    } catch (err) {
+      throw new Error(`Twitter fetcher was not set up properly (${err.message})`)
+    }
+
     bentReq(
       `https://api.twitter.com/1.1/statuses/show.json?id=${data.tweetId}&tweet_mode=extended`,
       null,
diff --git a/src/fetcher/xmpp.js b/src/fetcher/xmpp.js
index fa4c4db..ed02cf3 100644
--- a/src/fetcher/xmpp.js
+++ b/src/fetcher/xmpp.js
@@ -52,6 +52,14 @@ module.exports = async (data, opts) => {
   })
 
   const fetchPromise = new Promise(async (resolve, reject) => {
+    try {
+      validator.isFQDN(opts.claims.xmpp.service)
+      validator.isAscii(opts.claims.xmpp.username)
+      validator.isAscii(opts.claims.xmpp.password)
+    } catch (err) {
+      throw new Error(`XMPP fetcher was not set up properly (${err.message})`)
+    }
+
     if (!xmpp) {
       const xmppStartRes = await xmppStart(
         opts.service,