diff --git a/lib/index.js b/lib/index.js
index 080fe97..7743921 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1 +1 @@
-(()=>{"use strict";var e={800:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.FreeeAPIClient=void 0;const r=a(941);t.FreeeAPIClient=class{constructor(e,t){this.tokenManager=e,this.axios=t}get(e,t,a){return this.tokenManager.get(a).then((a=>{const r={Authorization:`Bearer ${a}`,"X-Api-Version":"2020-06-15","Content-Type":"application/json"};return this.axios.get(e,{params:t,headers:r})}))}post(e,t,a){return this.tokenManager.get(a).then((a=>{let s=t,i={},o="application/json";if("api/1/receipts"===e){const e=new r;Object.keys(t).forEach((a=>{e.append(a,t[a])})),s=e,i=e.getHeaders(),o="multipart/form-data"}return i.Authorization=`Bearer ${a}`,i["X-Api-Version"]="2020-06-15",i["Content-Type"]=o,this.axios.post(e,s,{maxContentLength:104857600,headers:i})}))}put(e,t,a){return this.tokenManager.get(a).then((a=>{const r={Authorization:`Bearer ${a}`,"X-Api-Version":"2020-06-15","Content-Type":"application/json"};return this.axios.put(e,t,{headers:r})}))}delete(e,t,a){return this.tokenManager.get(a).then((a=>{const r={Authorization:`Bearer ${a}`,"X-Api-Version":"2020-06-15","Content-Type":"application/json"};return this.axios.delete(e,{data:t,headers:r})}))}}},729:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.FreeeFirebaseAuthClient=void 0;const r=a(123);t.FreeeFirebaseAuthClient=class{constructor(e,t,a,s,i){this.admin=e,this.oauth2=t,this.axios=a,this.tokenManager=s;const o=i.freee,n=r.ConfigManager.getFunctionsConfigs();this.clientId=n.freee.client_id,this.clientSecret=n.freee.client_secret,this.redirectPath=r.ConfigManager.get(o,r.ConfigKeys.redirectPath),this.callbackPath=r.ConfigManager.get(o,r.ConfigKeys.callbackPath),this.companiesPath=r.ConfigManager.get(o,r.ConfigKeys.companiesPath),this.homePath=r.ConfigManager.get(o,r.ConfigKeys.homePath),this.appHost=r.ConfigManager.get(o,r.ConfigKeys.appHost),this.authHost=r.ConfigManager.get(o,r.ConfigKeys.authHost),this.apiKey=i.firebase&&i.firebase.apiKey}redirect(e){const t=this.oauth2.authorizationCode.authorizeURL({redirect_uri:`${this.authHost}${this.getCallbackPath()}`});e.redirect(t)}async callback(e,t){try{const a=await this.oauth2.authorizationCode.getToken({client_id:this.clientId,client_secret:this.clientSecret,code:e,redirect_uri:`${this.authHost}${this.getCallbackPath()}`}),r={accessToken:a.access_token,refreshToken:a.refresh_token,expiresIn:a.expires_in,createdAt:a.created_at},s=await this.getFreeeUser(r.accessToken),i=s.data.user.id,o=s.data.user.email,n=s.data.user.display_name?s.data.user.display_name:"",c=await this.createFirebaseAccount(i,o,n,r);t.redirect(`${this.appHost}${this.homePath}?token=${c}`)}catch(e){console.error("Some error occured on login process:",e),t.send(this.signInRefusedTemplate())}}getRedirectPath(){return this.redirectPath}getCallbackPath(){return this.callbackPath}getCompaniesPath(){return this.companiesPath}async createCryptoKey(e){await this.tokenManager.createCryptoKey(e)}getFreeeUser(e){return this.axios.get("/api/1/users/me?companies=true",{headers:{Authorization:`Bearer ${e}`}})}async createFirebaseAccount(e,t,a,r){const s=e.toString();return await this.tokenManager.save(s,t,r),await this.admin.auth().updateUser(s,{email:t,displayName:a}).catch((async e=>{if("auth/user-not-found"===e.code)return await this.admin.auth().createUser({uid:s,email:t,displayName:a});throw e})),await this.admin.auth().createCustomToken(s)}signInRefusedTemplate(){return`\n      <script>\n        window.location.href = '${this.appHost}'\n      <\/script>`}}},597:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0});const r=a(167),s=a(509),i=a(800),o=a(729),n=a(123),c=a(747),h=a(644);t.default=class{constructor(e,t){const u=e.freee;this.admin=t?s.initializeApp({credential:s.credential.cert(t),databaseURL:`https://${t.project_id}.firebaseio.com`,storageBucket:`${t.project_id}.appspot.com`}):s.initializeApp();const p=n.ConfigManager.get(e.firebase,n.ConfigKeys.cryptoKeyBucket),d=p?new c.default(this.admin.storage().bucket(p)):null,l=a(875).create(this.getCredentials(u)),f=new h.TokenManager(this.admin,l,d);r.default.defaults.baseURL=n.ConfigManager.get(u,n.ConfigKeys.apiHost),this.apiClient=new i.FreeeAPIClient(f,r.default),this.firebaseAuthClient=new o.FreeeFirebaseAuthClient(this.admin,l,r.default,f,e)}firebaseApp(){return this.admin}api(){return this.apiClient}auth(){return this.firebaseAuthClient}getCredentials(e){const t=n.ConfigManager.getFunctionsConfigs().freee;return{client:{id:t.client_id,secret:t.client_secret},auth:{tokenHost:n.ConfigManager.get(e,n.ConfigKeys.tokenHost),authorizePath:n.ConfigManager.get(e,n.ConfigKeys.authorizePath),tokenPath:n.ConfigManager.get(e,n.ConfigKeys.tokenPath)}}}}},123:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.ConfigManager=t.ConfigKeys=void 0;const r=a(860),s=(r.SUPPORTED_REGIONS,JSON.parse(process.env.FIREBASE_CONFIG).projectId),i=r.config().env&&r.config().env.region?r.config().env.region:"asia-northeast1";var o;!function(e){e.apiHost="apiHost",e.appHost="appHost",e.authHost="authHost",e.redirectPath="redirectPath",e.callbackPath="callbackPath",e.companiesPath="companiesPath",e.homePath="homePath",e.tokenHost="tokenHost",e.authorizePath="authorizePath",e.tokenPath="tokenPath",e.cryptoKeyBucket="cryptoKeyBucket"}(o=t.ConfigKeys||(t.ConfigKeys={}));const n={freee:[{key:o.apiHost,default:"https://api.freee.co.jp",production:"https://api.freee.co.jp"},{key:o.appHost,default:"http://localhost:5000",production:`https://${s}.web.app`},{key:o.authHost,default:`http://localhost:5001/${s}/${i}/api/auth`,production:`https://${i}-${s}.cloudfunctions.net/api/auth`},{key:o.redirectPath,default:"/redirect"},{key:o.callbackPath,default:"/callback"},{key:o.companiesPath,default:"/companies"},{key:o.homePath,default:"/"},{key:o.tokenHost,default:"https://accounts.secure.freee.co.jp",production:"https://accounts.secure.freee.co.jp"},{key:o.authorizePath,default:"/public_api/authorize"},{key:o.tokenPath,default:"/public_api/token"}],firebase:[{key:o.cryptoKeyBucket,default:`${s}.appspot.com`}]};t.ConfigManager=class{static get(e,t){return e&&this.hasKey(e,t)?e[t]:this.getDefaultValue(t)}static getFunctionsConfigs(){return r.config()}static getDefaultValue(e){const t=[].concat(n.freee).concat(n.firebase).find((t=>t.key===e));return this.isProduction()&&t.production?t.production:t.default}static isProduction(){const e=this.getFunctionsConfigs();return e.env&&"production"===e.env.mode}static hasKey(e,t){return Object.keys(e).find((e=>e===t))}}},747:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0});const r=a(146),s=a(347),i="aes-256-cbc",o="base64",n="utf8";t.default=class{constructor(e){this.bucket=e,this.keyCache={}}async createCryptoKey(e){const t=(0,r.format)(e,"yyyyMM");return this.create(t)}async encrypt(e){const{accessToken:t,refreshToken:a}=e,c=(0,r.format)(new Date,"yyyyMM"),h=await this.getKey(c),u=s.randomBytes(16);return Object.assign(Object.assign({},e),{accessToken:this.crypt(t,this.cipher(h,u),n,o),refreshToken:this.crypt(a,this.cipher(h,u),n,o),keyFileName:c,algorithm:i,iv:u})}async decrypt(e){const{accessToken:t,refreshToken:a,keyFileName:r,algorithm:s,iv:i}=e,c=await this.getKey(r);return Object.assign(Object.assign({},e),{accessToken:this.crypt(t,this.decipher(s,c,i),o,n),refreshToken:this.crypt(a,this.decipher(s,c,i),o,n)})}cipher(e,t){return s.createCipheriv(i,e,t)}decipher(e,t,a){return s.createDecipheriv(e,t,a)}async getKey(e){if(this.keyCache[e])return this.keyCache[e];try{return await this.get(e)}catch(t){return await this.exists(e)||(console.info("No key file for:",e),await this.create(e)),await this.get(e)}}crypt(e,t,a,r){let s=t.update(e,a,r);return s+=t.final(r),s}async create(e){const t=s.randomBytes(32),a=this.bucket.file(e);await a.save(t),console.log("New crypto key is successfully created for:",e)}async get(e){const t=await this.bucket.file(e).download();return this.keyCache[e]=t[0],console.log("Crypto key is retrieved from storage for:",e),t[0]}async exists(e){const t=(await this.bucket.file(e).exists())[0];return console.log(`Crypto key ${t?"is":"is not"} exists storage for:`,e),t}}},644:(e,t)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.TokenManager=void 0,t.TokenManager=class{constructor(e,t,a){this.admin=e,this.oauth2=t,this.cryptor=a,this.tokenCache={}}async get(e){const t=await this.getTokenFromFirebase(e);if(!this.tokenExpired(t))return t.accessToken;console.log("accessToken has been expired for user:",e);try{return await this.refreshToken(t,e)}catch(t){if(t.output&&401===t.output.statusCode){console.log("Token is already refreshed in other instance:",t);const a=await this.getTokenFromFirebase(e,!0);if(this.tokenExpired(a))throw console.error("Can not get available token:",t),t;return a.accessToken}throw t}}async save(e,t,a){const r=await this.encrypt(a);await this.admin.firestore().doc(`/freeeTokens/${e}`).set(Object.assign(Object.assign({},r),{email:t}))}async createCryptoKey(e){this.cryptor&&await this.cryptor.createCryptoKey(e)}async refreshToken(e,t){const a={access_token:e.accessToken,refresh_token:e.refreshToken,expires_in:e.expiresIn},r=this.oauth2.accessToken.create(a),s=await r.refresh(),i=await this.encrypt({accessToken:s.token.access_token,refreshToken:s.token.refresh_token,expiresIn:s.token.expires_in,createdAt:s.token.created_at});return this.tokenCache[t]=i,await this.admin.firestore().doc(`/freeeTokens/${t}`).set(Object.assign({},i),{merge:!0}),console.log("accessToken is successfully refreshed for user:",t),s.token.access_token}tokenExpired(e){const t=e.createdAt+e.expiresIn-300;return(new Date).getTime()/1e3>=t}async getTokenFromFirebase(e,t){if(!t){const t=this.tokenCache[e];if(t)return await this.decrypt(t)}const a=(await this.admin.firestore().doc(`/freeeTokens/${e}`).get()).data();return this.tokenCache[e]=a,console.log("Token is retrieved from firestore for user:",e),await this.decrypt(a)}async encrypt(e){return this.cryptor?await this.cryptor.encrypt(e):e}async decrypt(e){return this.cryptor?await this.cryptor.decrypt(e):e}}},167:e=>{e.exports=require("axios")},347:e=>{e.exports=require("crypto")},146:e=>{e.exports=require("date-fns")},509:e=>{e.exports=require("firebase-admin")},860:e=>{e.exports=require("firebase-functions")},941:e=>{e.exports=require("form-data")},875:e=>{e.exports=require("simple-oauth2")}},t={};function a(r){var s=t[r];if(void 0!==s)return s.exports;var i=t[r]={exports:{}};return e[r](i,i.exports,a),i.exports}var r={};for(var s in(()=>{var e=r;Object.defineProperty(e,"__esModule",{value:!0}),e.FreeeServerSDK=void 0;const t=a(597);e.FreeeServerSDK=t.default})(),r)this[s]=r[s];r.__esModule&&Object.defineProperty(this,"__esModule",{value:!0})})();
\ No newline at end of file
+(()=>{"use strict";var e={800:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.FreeeAPIClient=void 0;const s=a(941);t.FreeeAPIClient=class{constructor(e,t){this.tokenManager=e,this.axios=t}get(e,t,a,s){return this.tokenManager.get(a).then((a=>{const r=Object.assign({Authorization:`Bearer ${a}`,"X-Api-Version":"2020-06-15","Content-Type":"application/json"},s);return this.axios.get(e,{params:t,headers:r})}))}post(e,t,a,r){return this.tokenManager.get(a).then((a=>{let i=t,n={},o="application/json";if("api/1/receipts"===e){const e=new s;Object.keys(t).forEach((a=>{e.append(a,t[a])})),i=e,n=e.getHeaders(),o="multipart/form-data"}n.Authorization=`Bearer ${a}`,n["X-Api-Version"]="2020-06-15",n["Content-Type"]=o;const c=Object.assign(Object.assign({},n),r);return this.axios.post(e,i,{maxContentLength:104857600,headers:c})}))}put(e,t,a,s){return this.tokenManager.get(a).then((a=>{const r=Object.assign({Authorization:`Bearer ${a}`,"X-Api-Version":"2020-06-15","Content-Type":"application/json"},s);return this.axios.put(e,t,{headers:r})}))}delete(e,t,a,s){return this.tokenManager.get(a).then((a=>{const r=Object.assign({Authorization:`Bearer ${a}`,"X-Api-Version":"2020-06-15","Content-Type":"application/json"},s);return this.axios.delete(e,{data:t,headers:r})}))}}},729:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.FreeeFirebaseAuthClient=void 0;const s=a(123);t.FreeeFirebaseAuthClient=class{constructor(e,t,a,r,i){this.admin=e,this.oauth2=t,this.axios=a,this.tokenManager=r;const n=i.freee,o=s.ConfigManager.getFunctionsConfigs();this.clientId=o.freee.client_id,this.clientSecret=o.freee.client_secret,this.redirectPath=s.ConfigManager.get(n,s.ConfigKeys.redirectPath),this.callbackPath=s.ConfigManager.get(n,s.ConfigKeys.callbackPath),this.companiesPath=s.ConfigManager.get(n,s.ConfigKeys.companiesPath),this.homePath=s.ConfigManager.get(n,s.ConfigKeys.homePath),this.appHost=s.ConfigManager.get(n,s.ConfigKeys.appHost),this.authHost=s.ConfigManager.get(n,s.ConfigKeys.authHost),this.apiKey=i.firebase&&i.firebase.apiKey}redirect(e){const t=this.oauth2.authorizationCode.authorizeURL({redirect_uri:`${this.authHost}${this.getCallbackPath()}`});e.redirect(t)}async callback(e,t){try{const a=await this.oauth2.authorizationCode.getToken({client_id:this.clientId,client_secret:this.clientSecret,code:e,redirect_uri:`${this.authHost}${this.getCallbackPath()}`}),s={accessToken:a.access_token,refreshToken:a.refresh_token,expiresIn:a.expires_in,createdAt:a.created_at},r=await this.getFreeeUser(s.accessToken),i=r.data.user.id,n=r.data.user.email,o=r.data.user.display_name?r.data.user.display_name:"",c=await this.createFirebaseAccount(i,n,o,s);t.redirect(`${this.appHost}${this.homePath}?token=${c}`)}catch(e){console.error("Some error occured on login process:",e),t.send(this.signInRefusedTemplate())}}getRedirectPath(){return this.redirectPath}getCallbackPath(){return this.callbackPath}getCompaniesPath(){return this.companiesPath}async createCryptoKey(e){await this.tokenManager.createCryptoKey(e)}getFreeeUser(e){return this.axios.get("/api/1/users/me?companies=true",{headers:{Authorization:`Bearer ${e}`}})}async createFirebaseAccount(e,t,a,s){const r=e.toString();return await this.tokenManager.save(r,t,s),await this.admin.auth().updateUser(r,{email:t,displayName:a}).catch((async e=>{if("auth/user-not-found"===e.code)return await this.admin.auth().createUser({uid:r,email:t,displayName:a});throw e})),await this.admin.auth().createCustomToken(r)}signInRefusedTemplate(){return`\n      <script>\n        window.location.href = '${this.appHost}'\n      <\/script>`}}},597:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0});const s=a(167),r=a(509),i=a(800),n=a(729),o=a(123),c=a(747),h=a(644);t.default=class{constructor(e,t){const u=e.freee;this.admin=t?r.initializeApp({credential:r.credential.cert(t),databaseURL:`https://${t.project_id}.firebaseio.com`,storageBucket:`${t.project_id}.appspot.com`}):r.initializeApp();const p=o.ConfigManager.get(e.firebase,o.ConfigKeys.cryptoKeyBucket),d=p?new c.default(this.admin.storage().bucket(p)):null,l=a(875).create(this.getCredentials(u)),f=new h.TokenManager(this.admin,l,d);s.default.defaults.baseURL=o.ConfigManager.get(u,o.ConfigKeys.apiHost),this.apiClient=new i.FreeeAPIClient(f,s.default),this.firebaseAuthClient=new n.FreeeFirebaseAuthClient(this.admin,l,s.default,f,e)}firebaseApp(){return this.admin}api(){return this.apiClient}auth(){return this.firebaseAuthClient}getCredentials(e){const t=o.ConfigManager.getFunctionsConfigs().freee;return{client:{id:t.client_id,secret:t.client_secret},auth:{tokenHost:o.ConfigManager.get(e,o.ConfigKeys.tokenHost),authorizePath:o.ConfigManager.get(e,o.ConfigKeys.authorizePath),tokenPath:o.ConfigManager.get(e,o.ConfigKeys.tokenPath)}}}}},123:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.ConfigManager=t.ConfigKeys=void 0;const s=a(860),r=(s.SUPPORTED_REGIONS,JSON.parse(process.env.FIREBASE_CONFIG).projectId),i=s.config().env&&s.config().env.region?s.config().env.region:"asia-northeast1";var n;!function(e){e.apiHost="apiHost",e.appHost="appHost",e.authHost="authHost",e.redirectPath="redirectPath",e.callbackPath="callbackPath",e.companiesPath="companiesPath",e.homePath="homePath",e.tokenHost="tokenHost",e.authorizePath="authorizePath",e.tokenPath="tokenPath",e.cryptoKeyBucket="cryptoKeyBucket"}(n=t.ConfigKeys||(t.ConfigKeys={}));const o={freee:[{key:n.apiHost,default:"https://api.freee.co.jp",production:"https://api.freee.co.jp"},{key:n.appHost,default:"http://localhost:5000",production:`https://${r}.web.app`},{key:n.authHost,default:`http://localhost:5001/${r}/${i}/api/auth`,production:`https://${i}-${r}.cloudfunctions.net/api/auth`},{key:n.redirectPath,default:"/redirect"},{key:n.callbackPath,default:"/callback"},{key:n.companiesPath,default:"/companies"},{key:n.homePath,default:"/"},{key:n.tokenHost,default:"https://accounts.secure.freee.co.jp",production:"https://accounts.secure.freee.co.jp"},{key:n.authorizePath,default:"/public_api/authorize"},{key:n.tokenPath,default:"/public_api/token"}],firebase:[{key:n.cryptoKeyBucket,default:`${r}.appspot.com`}]};t.ConfigManager=class{static get(e,t){return e&&this.hasKey(e,t)?e[t]:this.getDefaultValue(t)}static getFunctionsConfigs(){return s.config()}static getDefaultValue(e){const t=[].concat(o.freee).concat(o.firebase).find((t=>t.key===e));return this.isProduction()&&t.production?t.production:t.default}static isProduction(){const e=this.getFunctionsConfigs();return e.env&&"production"===e.env.mode}static hasKey(e,t){return Object.keys(e).find((e=>e===t))}}},747:(e,t,a)=>{Object.defineProperty(t,"__esModule",{value:!0});const s=a(146),r=a(347),i="aes-256-cbc",n="base64",o="utf8";t.default=class{constructor(e){this.bucket=e,this.keyCache={}}async createCryptoKey(e){const t=(0,s.format)(e,"yyyyMM");return this.create(t)}async encrypt(e){const{accessToken:t,refreshToken:a}=e,c=(0,s.format)(new Date,"yyyyMM"),h=await this.getKey(c),u=r.randomBytes(16);return Object.assign(Object.assign({},e),{accessToken:this.crypt(t,this.cipher(h,u),o,n),refreshToken:this.crypt(a,this.cipher(h,u),o,n),keyFileName:c,algorithm:i,iv:u})}async decrypt(e){const{accessToken:t,refreshToken:a,keyFileName:s,algorithm:r,iv:i}=e,c=await this.getKey(s);return Object.assign(Object.assign({},e),{accessToken:this.crypt(t,this.decipher(r,c,i),n,o),refreshToken:this.crypt(a,this.decipher(r,c,i),n,o)})}cipher(e,t){return r.createCipheriv(i,e,t)}decipher(e,t,a){return r.createDecipheriv(e,t,a)}async getKey(e){if(this.keyCache[e])return this.keyCache[e];try{return await this.get(e)}catch(t){return await this.exists(e)||(console.info("No key file for:",e),await this.create(e)),await this.get(e)}}crypt(e,t,a,s){let r=t.update(e,a,s);return r+=t.final(s),r}async create(e){const t=r.randomBytes(32),a=this.bucket.file(e);await a.save(t),console.log("New crypto key is successfully created for:",e)}async get(e){const t=await this.bucket.file(e).download();return this.keyCache[e]=t[0],console.log("Crypto key is retrieved from storage for:",e),t[0]}async exists(e){const t=(await this.bucket.file(e).exists())[0];return console.log(`Crypto key ${t?"is":"is not"} exists storage for:`,e),t}}},644:(e,t)=>{Object.defineProperty(t,"__esModule",{value:!0}),t.TokenManager=void 0,t.TokenManager=class{constructor(e,t,a){this.admin=e,this.oauth2=t,this.cryptor=a,this.tokenCache={}}async get(e){const t=await this.getTokenFromFirebase(e);if(!this.tokenExpired(t))return t.accessToken;console.log("accessToken has been expired for user:",e);try{return await this.refreshToken(t,e)}catch(t){if(t.output&&401===t.output.statusCode){console.log("Token is already refreshed in other instance:",t);const a=await this.getTokenFromFirebase(e,!0);if(this.tokenExpired(a))throw console.error("Can not get available token:",t),t;return a.accessToken}throw t}}async save(e,t,a){const s=await this.encrypt(a);await this.admin.firestore().doc(`/freeeTokens/${e}`).set(Object.assign(Object.assign({},s),{email:t}))}async createCryptoKey(e){this.cryptor&&await this.cryptor.createCryptoKey(e)}async refreshToken(e,t){const a={access_token:e.accessToken,refresh_token:e.refreshToken,expires_in:e.expiresIn},s=this.oauth2.accessToken.create(a),r=await s.refresh(),i=await this.encrypt({accessToken:r.token.access_token,refreshToken:r.token.refresh_token,expiresIn:r.token.expires_in,createdAt:r.token.created_at});return this.tokenCache[t]=i,await this.admin.firestore().doc(`/freeeTokens/${t}`).set(Object.assign({},i),{merge:!0}),console.log("accessToken is successfully refreshed for user:",t),r.token.access_token}tokenExpired(e){const t=e.createdAt+e.expiresIn-300;return(new Date).getTime()/1e3>=t}async getTokenFromFirebase(e,t){if(!t){const t=this.tokenCache[e];if(t)return await this.decrypt(t)}const a=(await this.admin.firestore().doc(`/freeeTokens/${e}`).get()).data();return this.tokenCache[e]=a,console.log("Token is retrieved from firestore for user:",e),await this.decrypt(a)}async encrypt(e){return this.cryptor?await this.cryptor.encrypt(e):e}async decrypt(e){return this.cryptor?await this.cryptor.decrypt(e):e}}},167:e=>{e.exports=require("axios")},347:e=>{e.exports=require("crypto")},146:e=>{e.exports=require("date-fns")},509:e=>{e.exports=require("firebase-admin")},860:e=>{e.exports=require("firebase-functions")},941:e=>{e.exports=require("form-data")},875:e=>{e.exports=require("simple-oauth2")}},t={};function a(s){var r=t[s];if(void 0!==r)return r.exports;var i=t[s]={exports:{}};return e[s](i,i.exports,a),i.exports}var s={};for(var r in(()=>{var e=s;Object.defineProperty(e,"__esModule",{value:!0}),e.FreeeServerSDK=void 0;const t=a(597);e.FreeeServerSDK=t.default})(),s)this[r]=s[r];s.__esModule&&Object.defineProperty(this,"__esModule",{value:!0})})();
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
index 7423ec2..ff0403d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "freee-firebase-sdk",
-  "version": "2.1.1",
+  "version": "2.2.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "freee-firebase-sdk",
-      "version": "2.1.1",
+      "version": "2.2.0",
       "license": "MIT",
       "dependencies": {
         "@google-cloud/storage": "^6.3.0",
diff --git a/package.json b/package.json
index fabe5de..bb207c4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "freee-firebase-sdk",
-  "version": "2.1.1",
+  "version": "2.2.0",
   "license": "MIT",
   "homepage": "https://github.com/freee/firebase-sdk-js",
   "repository": {
diff --git a/src/sdk/api/freee-api-client.ts b/src/sdk/api/freee-api-client.ts
index db6393c..8806d40 100644
--- a/src/sdk/api/freee-api-client.ts
+++ b/src/sdk/api/freee-api-client.ts
@@ -1,5 +1,5 @@
 import { AxiosPromise, AxiosStatic } from 'axios'
-import { ParamJSON } from '../const/types'
+import { ParamJSON, CustomHeaders } from '../const/types'
 import { TokenManager } from '../services/token-manager'
 import * as FormData from 'form-data'
 
@@ -18,14 +18,17 @@ export class FreeeAPIClient {
   get<T = any>(
     url: string,
     params: ParamJSON,
-    userId: string
+    userId: string,
+    customHeaders?: CustomHeaders
   ): AxiosPromise<T> {
     return this.tokenManager.get(userId).then(accessToken => {
       const headers = {
         Authorization: `Bearer ${accessToken}`,
         'X-Api-Version': '2020-06-15',
-        'Content-Type': 'application/json'
+        'Content-Type': 'application/json',
+        ...customHeaders
       }
+
       return this.axios.get(url, {
         params: params,
         headers: headers
@@ -36,7 +39,12 @@ export class FreeeAPIClient {
   /**
    * Call freee api by POST
    */
-  post<T = any>(url: string, data: ParamJSON, userId: string): AxiosPromise<T> {
+  post<T = any>(
+    url: string,
+    data: ParamJSON,
+    userId: string,
+    customHeaders?: CustomHeaders
+  ): AxiosPromise<T> {
     return this.tokenManager.get(userId).then(accessToken => {
       let sendData = data
       let sendHeaders: { [key: string]: any } = {}
@@ -58,9 +66,14 @@ export class FreeeAPIClient {
       sendHeaders['X-Api-Version'] = '2020-06-15'
       sendHeaders['Content-Type'] = sendContentType
 
+      const headers = {
+        ...sendHeaders,
+        ...customHeaders
+      }
+
       return this.axios.post(url, sendData, {
         maxContentLength: maxContentLength,
-        headers: sendHeaders
+        headers: headers
       })
     })
   }
@@ -68,12 +81,18 @@ export class FreeeAPIClient {
   /**
    * Call freee api by PUT
    */
-  put<T = any>(url: string, data: ParamJSON, userId: string): AxiosPromise<T> {
+  put<T = any>(
+    url: string,
+    data: ParamJSON,
+    userId: string,
+    customHeaders?: CustomHeaders
+  ): AxiosPromise<T> {
     return this.tokenManager.get(userId).then(accessToken => {
       const headers = {
         Authorization: `Bearer ${accessToken}`,
         'X-Api-Version': '2020-06-15',
-        'Content-Type': 'application/json'
+        'Content-Type': 'application/json',
+        ...customHeaders
       }
       return this.axios.put(url, data, {
         headers: headers
@@ -84,12 +103,18 @@ export class FreeeAPIClient {
   /**
    * Call freee api by GET
    */
-  delete(url: string, data: ParamJSON, userId: string): AxiosPromise {
+  delete(
+    url: string,
+    data: ParamJSON,
+    userId: string,
+    customHeaders?: CustomHeaders
+  ): AxiosPromise {
     return this.tokenManager.get(userId).then(accessToken => {
       const headers = {
         Authorization: `Bearer ${accessToken}`,
         'X-Api-Version': '2020-06-15',
-        'Content-Type': 'application/json'
+        'Content-Type': 'application/json',
+        ...customHeaders
       }
       return this.axios.delete(url, {
         data: data,
diff --git a/src/sdk/const/types.ts b/src/sdk/const/types.ts
index a9c42a1..addaf72 100644
--- a/src/sdk/const/types.ts
+++ b/src/sdk/const/types.ts
@@ -2,6 +2,10 @@ export interface ParamJSON {
   [key: string]: any
 }
 
+export interface CustomHeaders {
+  [key: string]: any
+}
+
 export interface FreeeToken {
   accessToken: string
   refreshToken: string