diff --git a/src/main/java/com/avaje/ebean/config/CustomDbTypeMapping.java b/src/main/java/com/avaje/ebean/config/CustomDbTypeMapping.java
new file mode 100644
index 000000000..ae6a7d244
--- /dev/null
+++ b/src/main/java/com/avaje/ebean/config/CustomDbTypeMapping.java
@@ -0,0 +1,54 @@
+package com.avaje.ebean.config;
+
+import com.avaje.ebean.config.dbplatform.DbType;
+
+/**
+ * Custom mappings for DB types that override the default.
+ *
+ * @see ServerConfig#addCustomMapping(DbType, String)
+ */
+public class CustomDbTypeMapping {
+
+  protected final DbType type;
+
+  protected final String columnDefinition;
+
+  protected final Platform platform;
+
+  /**
+   * Create a mapping.
+   */
+  public CustomDbTypeMapping(DbType type, String columnDefinition, Platform platform) {
+    this.type = type;
+    this.columnDefinition = columnDefinition;
+    this.platform = platform;
+  }
+
+  /**
+   * Create a mapping that should apply to all the database platforms.
+   */
+  public CustomDbTypeMapping(DbType type, String columnDefinition) {
+    this(type, columnDefinition, null);
+  }
+
+  /**
+   * Return the DB type the mapping applies to.
+   */
+  public DbType getType() {
+    return type;
+  }
+
+  /**
+   * Return the DB column definition to use.
+   */
+  public String getColumnDefinition() {
+    return columnDefinition;
+  }
+
+  /**
+   * Return the platform this mapping should apply to. Null means it applied to all platforms.
+   */
+  public Platform getPlatform() {
+    return platform;
+  }
+}
diff --git a/src/main/java/com/avaje/ebean/config/DbMigrationConfig.java b/src/main/java/com/avaje/ebean/config/DbMigrationConfig.java
index ebb4d4889..5e4155289 100644
--- a/src/main/java/com/avaje/ebean/config/DbMigrationConfig.java
+++ b/src/main/java/com/avaje/ebean/config/DbMigrationConfig.java
@@ -1,7 +1,6 @@
 package com.avaje.ebean.config;
 
 import com.avaje.ebean.EbeanServer;
-import com.avaje.ebean.config.dbplatform.DbPlatformName;
 import com.avaje.ebean.dbmigration.DbMigration;
 import org.avaje.dbmigration.MigrationConfig;
 import org.avaje.dbmigration.MigrationRunner;
@@ -20,7 +19,7 @@ public class DbMigrationConfig {
   /**
    * The database platform to generate migration DDL for.
    */
-  protected DbPlatformName platform;
+  protected Platform platform;
 
   /**
    * Set to true if the DB migration should be generated on server start.
@@ -112,14 +111,14 @@ public class DbMigrationConfig {
    * We typically need to explicitly specify this as migration can often be generated
    * when running against H2.
    */
-  public DbPlatformName getPlatform() {
+  public Platform getPlatform() {
     return platform;
   }
 
   /**
    * Set the DB platform to generate migration DDL for.
    */
-  public void setPlatform(DbPlatformName platform) {
+  public void setPlatform(Platform platform) {
     this.platform = platform;
   }
 
@@ -366,7 +365,7 @@ public class DbMigrationConfig {
     includeGeneratedFileComment = properties.getBoolean("migration.includeGeneratedFileComment", includeGeneratedFileComment);
     generatePendingDrop = properties.get("migration.generatePendingDrop", generatePendingDrop);
 
-    platform = properties.getEnum(DbPlatformName.class, "migration.platform", platform);
+    platform = properties.getEnum(Platform.class, "migration.platform", platform);
 
     generate = properties.getBoolean("migration.generate", generate);
     version = properties.get("migration.version", version);
diff --git a/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformName.java b/src/main/java/com/avaje/ebean/config/Platform.java
similarity index 84%
rename from src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformName.java
rename to src/main/java/com/avaje/ebean/config/Platform.java
index 357e89b21..bba8d43e2 100644
--- a/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformName.java
+++ b/src/main/java/com/avaje/ebean/config/Platform.java
@@ -1,9 +1,9 @@
-package com.avaje.ebean.config.dbplatform;
+package com.avaje.ebean.config;
 
 /**
  * Built in supported platforms.
  */
-public enum DbPlatformName {
+public enum Platform {
 
   /**
    * Generic base platform configured via properties or code.
diff --git a/src/main/java/com/avaje/ebean/config/ServerConfig.java b/src/main/java/com/avaje/ebean/config/ServerConfig.java
index 9dd0d05bb..70cf6dbcf 100644
--- a/src/main/java/com/avaje/ebean/config/ServerConfig.java
+++ b/src/main/java/com/avaje/ebean/config/ServerConfig.java
@@ -7,6 +7,7 @@ import com.avaje.ebean.cache.ServerCacheManager;
 import com.avaje.ebean.cache.ServerCachePlugin;
 import com.avaje.ebean.config.dbplatform.DatabasePlatform;
 import com.avaje.ebean.config.dbplatform.DbEncrypt;
+import com.avaje.ebean.config.dbplatform.DbType;
 import com.avaje.ebean.event.BeanFindController;
 import com.avaje.ebean.event.BeanPersistController;
 import com.avaje.ebean.event.BeanPersistListener;
@@ -83,6 +84,8 @@ public class ServerConfig {
 
   private ContainerConfig containerConfig;
 
+  private List<CustomDbTypeMapping> customDbTypeMappings = new ArrayList<CustomDbTypeMapping>();
+
   /**
    * The underlying properties that were used during configuration.
    */
@@ -1437,7 +1440,7 @@ public class ServerConfig {
    * <p>
    * You can also set this in ebean.proprerties:
    * </p>
-   *
+   * <p>
    * <pre>{@code
    * # set via ebean.properties
    * ebean.encryptKeyManager=com.avaje.tests.basic.encrypt.BasicEncyptKeyManager
@@ -1770,7 +1773,7 @@ public class ServerConfig {
    * queries that normally hit L2 bean cache automatically will not do so after a write/persist
    * on the transaction.
    * </p>
-   *
+   * <p>
    * <pre>{@code
    *
    *   // assume Customer has L2 bean caching enabled ...
@@ -1932,6 +1935,54 @@ public class ServerConfig {
     this.resourceDirectory = resourceDirectory;
   }
 
+  /**
+   * Add a custom type mapping.
+   * <p>
+   * <pre>{@code
+   *
+   *   // set the default mapping for BigDecimal.class/decimal
+   *   serverConfig.addCustomMapping(DbType.DECIMAL, "decimal(18,6)");
+   *
+   *   // set the default mapping for String.class/varchar but only for Postgres
+   *   serverConfig.addCustomMapping(DbType.VARCHAR, "text", Platform.POSTGRES);
+   *
+   * }</pre>
+   *
+   * @param type             The DB type this mapping should apply to
+   * @param columnDefinition The column definition that should be used
+   * @param platform         Optionally specify the platform this mapping should apply to.
+   */
+  public void addCustomMapping(DbType type, String columnDefinition, Platform platform) {
+    customDbTypeMappings.add(new CustomDbTypeMapping(type, columnDefinition, platform));
+  }
+
+  /**
+   * Add a custom type mapping that applies to all platforms.
+   * <p>
+   * <pre>{@code
+   *
+   *   // set the default mapping for BigDecimal/decimal
+   *   serverConfig.addCustomMapping(DbType.DECIMAL, "decimal(18,6)");
+   *
+   *   // set the default mapping for String/varchar
+   *   serverConfig.addCustomMapping(DbType.VARCHAR, "text");
+   *
+   * }</pre>
+   *
+   * @param type             The DB type this mapping should apply to
+   * @param columnDefinition The column definition that should be used
+   */
+  public void addCustomMapping(DbType type, String columnDefinition) {
+    customDbTypeMappings.add(new CustomDbTypeMapping(type, columnDefinition));
+  }
+
+  /**
+   * Return the list of custom type mappings.
+   */
+  public List<CustomDbTypeMapping> getCustomTypeMappings() {
+    return customDbTypeMappings;
+  }
+
   /**
    * Register a BeanQueryAdapter instance.
    * <p>
diff --git a/src/main/java/com/avaje/ebean/config/dbplatform/DatabasePlatform.java b/src/main/java/com/avaje/ebean/config/dbplatform/DatabasePlatform.java
index 9416cc7ba..6289dd810 100644
--- a/src/main/java/com/avaje/ebean/config/dbplatform/DatabasePlatform.java
+++ b/src/main/java/com/avaje/ebean/config/dbplatform/DatabasePlatform.java
@@ -2,7 +2,9 @@ package com.avaje.ebean.config.dbplatform;
 
 import com.avaje.ebean.BackgroundExecutor;
 import com.avaje.ebean.Query;
+import com.avaje.ebean.config.CustomDbTypeMapping;
 import com.avaje.ebean.config.PersistBatch;
+import com.avaje.ebean.config.Platform;
 import com.avaje.ebean.config.ServerConfig;
 import com.avaje.ebean.dbmigration.ddlgeneration.DdlHandler;
 import com.avaje.ebean.dbmigration.ddlgeneration.platform.PlatformDdl;
@@ -180,6 +182,19 @@ public class DatabasePlatform {
    */
   public void configure(ServerConfig serverConfig) {
     dbTypeMap.config(nativeUuidType, serverConfig.getDbUuid());
+    for (CustomDbTypeMapping mapping : serverConfig.getCustomTypeMappings()) {
+      if (platformMatch(mapping.getPlatform())) {
+        dbTypeMap.put(mapping.getType(), parse(mapping.getColumnDefinition()));
+      }
+    }
+  }
+
+  private DbPlatformType parse(String columnDefinition) {
+    return DbPlatformType.parse(columnDefinition);
+  }
+
+  private boolean platformMatch(Platform platform) {
+    return platform == null || platform.name().equalsIgnoreCase(name);
   }
 
   /**
diff --git a/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformType.java b/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformType.java
index 5ff8c2c6e..c2599d7aa 100644
--- a/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformType.java
+++ b/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformType.java
@@ -28,6 +28,17 @@ public class DbPlatformType implements ExtraDbTypes {
    */
   private final boolean canHaveLength;
 
+  /**
+   * Parse a type definition into a DbPlatformType.
+   * <p>
+   * e.g. "decimal(18,6)"
+   * e.g. "text"
+   * </p>
+   */
+  public static DbPlatformType parse(String columnDefinition) {
+    return DbPlatformTypeParser.parse(columnDefinition);
+  }
+
   /**
    * Construct with no length or scale.
    */
@@ -67,6 +78,27 @@ public class DbPlatformType implements ExtraDbTypes {
     this.canHaveLength = canHaveLength;
   }
 
+  /**
+   * Return the type name.
+   */
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Return the default length/precision.
+   */
+  public int getDefaultLength() {
+    return defaultLength;
+  }
+
+  /**
+   * Return the default scale.
+   */
+  public int getDefaultScale() {
+    return defaultScale;
+  }
+
   /**
    * Return the type for a specific property that incorporates the name, length,
    * precision and scale.
diff --git a/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformTypeParser.java b/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformTypeParser.java
new file mode 100644
index 000000000..14a1c60db
--- /dev/null
+++ b/src/main/java/com/avaje/ebean/config/dbplatform/DbPlatformTypeParser.java
@@ -0,0 +1,40 @@
+package com.avaje.ebean.config.dbplatform;
+
+/**
+ * Parse raw column definitions into DbPlatformType like "decimal(18,6)" and "varchar(20) and "json".
+ */
+class DbPlatformTypeParser {
+
+  /**
+   * Parse the column definition and return the DbPlatformType.
+   */
+  static DbPlatformType parse(String columnDefinition) {
+
+    columnDefinition = columnDefinition.trim();
+
+    int openPos = columnDefinition.indexOf('(');
+    if (openPos == -1) {
+      return new DbPlatformType(columnDefinition);
+    }
+    int closePos = columnDefinition.indexOf(')', openPos);
+    if (closePos == -1) {
+      return new DbPlatformType(columnDefinition);
+    }
+    try {
+      int commaPos = columnDefinition.indexOf(',', openPos);
+      if (commaPos > -1) {
+        String type = columnDefinition.substring(0, openPos);
+        int scale = Integer.parseInt(columnDefinition.substring(openPos + 1, commaPos));
+        int precision = Integer.parseInt(columnDefinition.substring(commaPos + 1, closePos));
+        return new DbPlatformType(type, scale, precision);
+
+      } else {
+        String type = columnDefinition.substring(0, openPos);
+        int scale = Integer.parseInt(columnDefinition.substring(openPos + 1, closePos));
+        return new DbPlatformType(type, scale);
+      }
+    } catch (RuntimeException e) {
+      return new DbPlatformType(columnDefinition);
+    }
+  }
+}
diff --git a/src/main/java/com/avaje/ebean/dbmigration/DbMigration.java b/src/main/java/com/avaje/ebean/dbmigration/DbMigration.java
index 18fff98cb..06692d82c 100644
--- a/src/main/java/com/avaje/ebean/dbmigration/DbMigration.java
+++ b/src/main/java/com/avaje/ebean/dbmigration/DbMigration.java
@@ -7,7 +7,7 @@ import com.avaje.ebean.config.DbMigrationConfig;
 import com.avaje.ebean.config.ServerConfig;
 import com.avaje.ebean.config.dbplatform.DB2Platform;
 import com.avaje.ebean.config.dbplatform.DatabasePlatform;
-import com.avaje.ebean.config.dbplatform.DbPlatformName;
+import com.avaje.ebean.config.Platform;
 import com.avaje.ebean.config.dbplatform.H2Platform;
 import com.avaje.ebean.config.dbplatform.MsSqlServer2005Platform;
 import com.avaje.ebean.config.dbplatform.MySqlPlatform;
@@ -139,7 +139,7 @@ public class DbMigration {
    * If not set this defaults to the platform of the default server.
    * </p>
    */
-  public void setPlatform(DbPlatformName platform) {
+  public void setPlatform(Platform platform) {
     setPlatform(getPlatform(platform));
   }
 
@@ -163,7 +163,7 @@ public class DbMigration {
    * from the migration (e.g. generate migration sql for MySql, Postgres and Oracle).
    * </p>
    */
-  public void addPlatform(DbPlatformName platform, String prefix) {
+  public void addPlatform(Platform platform, String prefix) {
     platforms.add(new Pair(getPlatform(platform), prefix));
   }
 
@@ -515,7 +515,7 @@ public class DbMigration {
   /**
    * Return the DatabasePlatform given the platform key.
    */
-  protected DatabasePlatform getPlatform(DbPlatformName platform) {
+  protected DatabasePlatform getPlatform(Platform platform) {
     switch (platform) {
       case H2:
         return new H2Platform();
diff --git a/src/main/java/com/avaje/ebean/dbmigration/DbOffline.java b/src/main/java/com/avaje/ebean/dbmigration/DbOffline.java
index f0f8c3783..fb25efb57 100644
--- a/src/main/java/com/avaje/ebean/dbmigration/DbOffline.java
+++ b/src/main/java/com/avaje/ebean/dbmigration/DbOffline.java
@@ -1,6 +1,6 @@
 package com.avaje.ebean.dbmigration;
 
-import com.avaje.ebean.config.dbplatform.DbPlatformName;
+import com.avaje.ebean.config.Platform;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -19,7 +19,7 @@ public class DbOffline {
   /**
    * Set the platform to use when creating the next EbeanServer instance.
    */
-  public static void setPlatform(DbPlatformName dbPlatform) {
+  public static void setPlatform(Platform dbPlatform) {
     System.setProperty(KEY, dbPlatform.name());
   }
 
@@ -41,7 +41,7 @@ public class DbOffline {
    * Bring up the next EbeanServer instance using the H2 platform.
    */
   public static void asH2() {
-    setPlatform(DbPlatformName.H2);
+    setPlatform(Platform.H2);
   }
 
   /**
diff --git a/src/test/java/com/avaje/ebean/config/PropertiesWrapperTest.java b/src/test/java/com/avaje/ebean/config/PropertiesWrapperTest.java
index 43f8606c9..6337548ac 100644
--- a/src/test/java/com/avaje/ebean/config/PropertiesWrapperTest.java
+++ b/src/test/java/com/avaje/ebean/config/PropertiesWrapperTest.java
@@ -1,6 +1,5 @@
 package com.avaje.ebean.config;
 
-import com.avaje.ebean.config.dbplatform.DbPlatformName;
 import org.junit.Test;
 
 import java.util.Properties;
@@ -25,9 +24,9 @@ public class PropertiesWrapperTest {
     properties.put("platform","postgres");
 
     PropertiesWrapper pw = new PropertiesWrapper("pref", "myserver", properties);
-    assertEquals(DbPlatformName.POSTGRES, pw.getEnum(DbPlatformName.class, "platform", DbPlatformName.H2));
-    assertEquals(DbPlatformName.H2, pw.getEnum(DbPlatformName.class, "junk", DbPlatformName.H2));
-    assertNull(pw.getEnum(DbPlatformName.class, "junk", null));
+    assertEquals(Platform.POSTGRES, pw.getEnum(Platform.class, "platform", Platform.H2));
+    assertEquals(Platform.H2, pw.getEnum(Platform.class, "junk", Platform.H2));
+    assertNull(pw.getEnum(Platform.class, "junk", null));
   }
 
   @Test
diff --git a/src/test/java/com/avaje/ebean/config/dbplatform/DatabasePlatformTest.java b/src/test/java/com/avaje/ebean/config/dbplatform/DatabasePlatformTest.java
new file mode 100644
index 000000000..923834382
--- /dev/null
+++ b/src/test/java/com/avaje/ebean/config/dbplatform/DatabasePlatformTest.java
@@ -0,0 +1,46 @@
+package com.avaje.ebean.config.dbplatform;
+
+import com.avaje.ebean.config.Platform;
+import com.avaje.ebean.config.ServerConfig;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class DatabasePlatformTest {
+
+  @Test
+  public void defaultTypesForDecimalAndVarchar() throws Exception {
+
+    DatabasePlatform dbPlatform = new DatabasePlatform();
+    assertEquals(defaultDecimalDefn(dbPlatform), "decimal(38)");
+    assertEquals(defaultDefn(DbType.VARCHAR, dbPlatform), "varchar(255)");
+  }
+
+  @Test
+  public void configure_customType() throws Exception {
+
+    ServerConfig serverConfig = new ServerConfig();
+    serverConfig.addCustomMapping(DbType.VARCHAR, "text", Platform.POSTGRES);
+    serverConfig.addCustomMapping(DbType.DECIMAL, "decimal(24,4)");
+
+    // PG renders custom decimal and varchar
+    PostgresPlatform pgPlatform = new PostgresPlatform();
+    pgPlatform.configure(serverConfig);
+    assertEquals(defaultDecimalDefn(pgPlatform), "decimal(24,4)");
+    assertEquals(defaultDefn(DbType.VARCHAR, pgPlatform), "text");
+
+    // H2 only renders custom decimal
+    H2Platform h2Platform = new H2Platform();
+    h2Platform.configure(serverConfig);
+    assertEquals(defaultDecimalDefn(h2Platform), "decimal(24,4)");
+    assertEquals(defaultDefn(DbType.VARCHAR, h2Platform), "varchar(255)");
+  }
+
+  private String defaultDecimalDefn(DatabasePlatform dbPlatform) {
+    return defaultDefn(DbType.DECIMAL, dbPlatform);
+  }
+
+  private String defaultDefn(DbType type, DatabasePlatform dbPlatform) {
+    return dbPlatform.getDbTypeMap().get(type).renderType(0, 0);
+  }
+}
\ No newline at end of file
diff --git a/src/test/java/com/avaje/ebean/config/dbplatform/DbPlatformTypeParserTest.java b/src/test/java/com/avaje/ebean/config/dbplatform/DbPlatformTypeParserTest.java
new file mode 100644
index 000000000..bc2990515
--- /dev/null
+++ b/src/test/java/com/avaje/ebean/config/dbplatform/DbPlatformTypeParserTest.java
@@ -0,0 +1,67 @@
+package com.avaje.ebean.config.dbplatform;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class DbPlatformTypeParserTest {
+
+  @Test
+  public void parse_text() throws Exception {
+
+    DbPlatformType type = DbPlatformTypeParser.parse("text");
+
+    assertEquals(type.getName(), "text");
+    assertEquals(type.getDefaultLength(), 0);
+    assertEquals(type.getDefaultScale(), 0);
+
+    assertEquals(type.renderType(0, 0), "text");
+    assertEquals(type.renderType(40, 0), "text(40)");
+  }
+
+  @Test
+  public void parse_varchar20() throws Exception {
+
+    DbPlatformType type = DbPlatformTypeParser.parse("varchar(20)");
+
+    assertEquals(type.getName(), "varchar");
+    assertEquals(type.getDefaultLength(), 20);
+    assertEquals(type.getDefaultScale(), 0);
+
+    assertEquals(type.renderType(0, 0), "varchar(20)");
+    assertEquals(type.renderType(40, 0), "varchar(40)");
+  }
+
+  @Test
+  public void parse_decimal_18_6() throws Exception {
+
+    DbPlatformType type = DbPlatformTypeParser.parse("decimal(18,6)");
+
+    assertEquals(type.getName(), "decimal");
+    assertEquals(type.getDefaultLength(), 18);
+    assertEquals(type.getDefaultScale(), 6);
+    assertEquals(type.renderType(0, 0), "decimal(18,6)");
+  }
+
+  @Test
+  public void parse_something() throws Exception {
+
+    DbPlatformType type = DbPlatformTypeParser.parse("something(asd,6)");
+
+    assertEquals(type.getName(), "something(asd,6)");
+    assertEquals(type.getDefaultLength(), 0);
+    assertEquals(type.getDefaultScale(), 0);
+    assertEquals(type.renderType(0, 0), "something(asd,6)");
+  }
+
+  @Test
+  public void parse_invalid() throws Exception {
+
+    DbPlatformType type = DbPlatformTypeParser.parse("something(asd");
+
+    assertEquals(type.getName(), "something(asd");
+    assertEquals(type.getDefaultLength(), 0);
+    assertEquals(type.getDefaultScale(), 0);
+    assertEquals(type.renderType(0, 0), "something(asd");
+  }
+}
\ No newline at end of file