diff --git a/lib/contracts/contribution.js b/lib/contracts/contribution.js
index 6398458..e49591a 100644
--- a/lib/contracts/contribution.js
+++ b/lib/contracts/contribution.js
@@ -1,20 +1,5 @@
 const ethers = require('ethers');
 
-const schemas = require('kosmos-schemas');
-const tv4 = require('tv4');
-const validator = tv4.freshApi();
-
-validator.addFormat({
-  'date': function(value) {
-    const dateRegexp = /^[0-9]{4,}-[0-9]{2}-[0-9]{2}$/;
-    return dateRegexp.test(value) ? null : "A valid ISO 8601 full-date string is expected";
-  },
-  'time': function(value) {
-    const timeRegexp = /^([01][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9]|60)(\.[0-9]+)?(([Zz])|([\+|\-]([01][0-9]|2[0-3]):[0-5][0-9]))$/;
-    return timeRegexp.test(value) ? null : "A valid ISO 8601 full-time string is expected";
-  }
-})
-
 const ContributionSerializer = require('../serializers/contribution');
 const Base = require('./base');
 
@@ -62,12 +47,13 @@ class Contribution extends Base {
       });
   }
 
-  addContribution(contributionAttr, callOptions = {}) {
-    let jsonStr = ContributionSerializer.serialize(contributionAttr);
+  async addContribution(contributionAttr, callOptions = {}) {
+    const contribution = new ContributionSerializer(contributionAttr);
 
-    // Validate JSON document against schema
-    let result = validator.validate(JSON.parse(jsonStr), schemas['contribution']);
-    if (!result) { return Promise.reject(validator.error); }
+    try { await contribution.validate(); }
+    catch (error) { return Promise.reject(error); }
+
+    const jsonStr = contribution.serialize();
 
     return this.ipfs
       .add(jsonStr)
diff --git a/lib/serializers/contribution.js b/lib/serializers/contribution.js
index 6cdc279..8ed8dee 100644
--- a/lib/serializers/contribution.js
+++ b/lib/serializers/contribution.js
@@ -1,45 +1,24 @@
+const schemas = require('kosmos-schemas');
+const validator = require('../utils/validator');
+
 /**
- * Handle serialization for JSON-LD object of the contribution, according to
- * https://github.com/67P/kosmos-schemas/blob/master/schemas/contribution.json
+ * Serialization and validation for JSON-LD document of the contribution.
  *
  * @class
  * @public
  */
 class Contribution {
- /**
-  * Deserialize JSON to object
-  *
-  * @method
-  * @public
-  */
-  static deserialize(serialized) {
-    let {
-      date,
-      time,
-      kind,
-      description,
-      details,
-      url,
-    } = JSON.parse(serialized.toString('utf8'));
 
-    return {
-      date,
-      time,
-      kind,
-      description,
-      details,
-      url,
-      ipfsData: serialized,
-    };
+  constructor(attrs) {
+    Object.keys(attrs).forEach(a => this[a] = attrs[a]);
   }
 
- /**
-  * Serialize object to JSON
-  *
-  * @method
-  * @public
-  */
-  static serialize(deserialized) {
+  /**
+   * Serialize object to JSON
+   *
+   * @public
+   */
+  serialize () {
     let {
       contributorIpfsHash,
       date,
@@ -48,7 +27,7 @@ class Contribution {
       description,
       url,
       details
-    } = deserialized;
+    } = this;
 
     let data = {
       "@context": "https://schema.kosmos.org",
@@ -70,6 +49,44 @@ class Contribution {
     // Write it pretty to ipfs
     return JSON.stringify(data, null, 2);
   }
+
+  /**
+   * Validate serialized data against schema
+   *
+   * @public
+   */
+  validate () {
+    const serialized = JSON.parse(this.serialize());
+    const valid = validator.validate(serialized, schemas['contribution']);
+    return valid ? Promise.resolve() : Promise.reject(validator.error);
+  }
+
+  /**
+   * Deserialize JSON to object
+   *
+   * @public
+   */
+  static deserialize (serialized) {
+    let {
+      date,
+      time,
+      kind,
+      description,
+      details,
+      url,
+    } = JSON.parse(serialized.toString('utf8'));
+
+    return {
+      date,
+      time,
+      kind,
+      description,
+      details,
+      url,
+      ipfsData: serialized,
+    };
+  }
+
 }
 
 module.exports = Contribution;
diff --git a/lib/utils/validator.js b/lib/utils/validator.js
new file mode 100644
index 0000000..1dde313
--- /dev/null
+++ b/lib/utils/validator.js
@@ -0,0 +1,15 @@
+const tv4 = require('tv4');
+const validator = tv4.freshApi();
+
+validator.addFormat({
+  'date': function(value) {
+    const dateRegexp = /^[0-9]{4,}-[0-9]{2}-[0-9]{2}$/;
+    return dateRegexp.test(value) ? null : "A valid ISO 8601 full-date string is expected";
+  },
+  'time': function(value) {
+    const timeRegexp = /^([01][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9]|60)(\.[0-9]+)?(([Zz])|([\+|\-]([01][0-9]|2[0-3]):[0-5][0-9]))$/;
+    return timeRegexp.test(value) ? null : "A valid ISO 8601 full-time string is expected";
+  }
+})
+
+module.exports = validator;