diff --git a/project.clj b/project.clj
index 5a1629f..b97c869 100644
--- a/project.clj
+++ b/project.clj
@@ -1,4 +1,4 @@
-(defproject mongo-driver-3 "0.1.0"
+(defproject mongo-driver-3 "0.2.0-SNAPSHOT"
   :description "A Clojure wrapper for the Java MongoDB driver 3.11+."
   :url "https://github.com/gnarroway/mongo-driver-3"
   :license {:name         "The MIT License"
diff --git a/src/mongo_driver_3/operator.clj b/src/mongo_driver_3/operator.clj
new file mode 100644
index 0000000..1893a8f
--- /dev/null
+++ b/src/mongo_driver_3/operator.clj
@@ -0,0 +1,282 @@
+(ns mongo-driver-3.operator
+  "Define constants corresponding to mongo operators")
+
+(defmacro defoperator
+  [op]
+  `(def ^{:const true} ~op ~(str op)))
+
+;;; --- Query operators
+;;; https://docs.mongodb.com/manual/reference/operator/query/
+
+;;; Comparison
+
+(defoperator $eq)
+(defoperator $gt)
+(defoperator $gte)
+(defoperator $in)
+(defoperator $lt)
+(defoperator $lte)
+(defoperator $ne)
+(defoperator $nin)
+
+;;; Logical
+
+(defoperator $and)
+(defoperator $not)
+(defoperator $nor)
+(defoperator $or)
+
+;;; Element
+
+(defoperator $exists)
+(defoperator $type)
+
+;;; Evaluation
+
+(defoperator $expr)
+(defoperator $jsonSchema)
+(defoperator $mod)
+(defoperator $regex)
+(defoperator $text)
+(defoperator $where)
+
+;;; Geospatial
+
+(defoperator $geoIntersects)
+(defoperator $geoWithin)
+(defoperator $near)
+(defoperator $geoSphere)
+
+;;; Array
+
+(defoperator $all)
+(defoperator $elemMatch)
+(defoperator $size)
+
+;;; Bitwise
+
+(defoperator $bitsAllClear)
+(defoperator $bitsAllSet)
+(defoperator $bitsAnyClear)
+(defoperator $bitsAnySet)
+
+;;; Comments
+
+(defoperator $comment)
+
+;;; Projection
+
+(defoperator $)
+(defoperator $meta)
+(defoperator $slice)
+
+;;; --- Update operators
+;;; https://docs.mongodb.com/manual/reference/operator/update/
+
+;;; Fields
+
+(defoperator $currentDate)
+(defoperator $inc)
+(defoperator $min)
+(defoperator $max)
+(defoperator $mul)
+(defoperator $rename)
+(defoperator $set)
+(defoperator $setOnInsert)
+(defoperator $unset)
+
+;;; Array operators
+
+(defoperator $addToSet)
+(defoperator $pop)
+(defoperator $pull)
+(defoperator $push)
+(defoperator $pushAll)
+
+;;; Array modifiers
+
+(defoperator $each)
+(defoperator $position)
+(defoperator $slice)
+(defoperator $sort)
+
+;;; Bitwise
+
+(defoperator $bit)
+
+;;; --- Aggregation stages
+;;; https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/
+
+(defoperator $addFields)
+(defoperator $bucket)
+(defoperator $bucketAuto)
+(defoperator $collStats)
+(defoperator $count)
+(defoperator $currentOp)
+(defoperator $facet)
+(defoperator $geoNear)
+(defoperator $graphLookup)
+(defoperator $group)
+(defoperator $indexStats)
+(defoperator $limit)
+(defoperator $listLocalSessions)
+(defoperator $listSessions)
+(defoperator $lookup)
+(defoperator $match)
+(defoperator $merge)
+(defoperator $out)
+(defoperator $planCacheStats)
+(defoperator $project)
+(defoperator $redact)
+(defoperator $replaceRoot)
+(defoperator $replaceWith)
+(defoperator $sample)
+(defoperator $set)
+(defoperator $skip)
+(defoperator $sort)
+(defoperator $sortByCount)
+(defoperator $unset)
+(defoperator $unwind)
+
+
+;;; --- Aggregation operators
+;;; https://docs.mongodb.com/manual/reference/operator/aggregation/
+
+
+(defoperator $abs)
+(defoperator $acos)
+(defoperator $acosh)
+(defoperator $add)
+(defoperator $addToSet)
+(defoperator $allElementsTrue)
+(defoperator $and)
+(defoperator $anyElementTrue)
+(defoperator $arrayElemAt)
+(defoperator $arrayToObject)
+(defoperator $asin)
+(defoperator $asinh)
+(defoperator $atan)
+(defoperator $atan2)
+(defoperator $atanh)
+(defoperator $avg)
+(defoperator $ceil)
+(defoperator $cmp)
+(defoperator $concat)
+(defoperator $concatArrays)
+(defoperator $cond)
+(defoperator $convert)
+(defoperator $cos)
+(defoperator $dateFromParts)
+(defoperator $dateToParts)
+(defoperator $dateFromString)
+(defoperator $dateToString)
+(defoperator $dayOfMonth)
+(defoperator $dayOfWeek)
+(defoperator $dayOfYear)
+(defoperator $degreesToRadians)
+(defoperator $divide)
+(defoperator $eq)
+(defoperator $exp)
+(defoperator $filter)
+(defoperator $first)
+(defoperator $floor)
+(defoperator $gt)
+(defoperator $gte)
+(defoperator $hour)
+(defoperator $ifNull)
+(defoperator $in)
+(defoperator $indexOfArray)
+(defoperator $indexOfBytes)
+(defoperator $indexOfCP)
+(defoperator $isArray)
+(defoperator $isoDayOfWeek)
+(defoperator $isoWeek)
+(defoperator $isoWeekYear)
+(defoperator $last)
+(defoperator $let)
+(defoperator $literal)
+(defoperator $ln)
+(defoperator $log)
+(defoperator $log10)
+(defoperator $lt)
+(defoperator $lte)
+(defoperator $ltrim)
+(defoperator $map)
+(defoperator $max)
+(defoperator $mergeObjects)
+(defoperator $meta)
+(defoperator $min)
+(defoperator $millisecond)
+(defoperator $minute)
+(defoperator $mod)
+(defoperator $month)
+(defoperator $multiply)
+(defoperator $ne)
+(defoperator $not)
+(defoperator $objectToArray)
+(defoperator $or)
+(defoperator $pow)
+(defoperator $push)
+(defoperator $radiansToDegrees)
+(defoperator $range)
+(defoperator $reduce)
+(defoperator $regexFind)
+(defoperator $regexFindAll)
+(defoperator $regexMatch)
+(defoperator $reverseArray)
+(defoperator $round)
+(defoperator $rtrim)
+(defoperator $second)
+(defoperator $setDifference)
+(defoperator $setEquals)
+(defoperator $setIntersection)
+(defoperator $setIsSubset)
+(defoperator $setUnion)
+(defoperator $size)
+(defoperator $sin)
+(defoperator $slice)
+(defoperator $split)
+(defoperator $sqrt)
+(defoperator $stdDevPop)
+(defoperator $stdDevSamp)
+(defoperator $strcasecmp)
+(defoperator $strLenBytes)
+(defoperator $strLenCP)
+(defoperator $substr)
+(defoperator $substrBytes)
+(defoperator $substrCP)
+(defoperator $subtract)
+(defoperator $sum)
+(defoperator $switch)
+(defoperator $tan)
+(defoperator $toBool)
+(defoperator $toDate)
+(defoperator $toDecimal)
+(defoperator $toDouble)
+(defoperator $toInt)
+(defoperator $toLong)
+(defoperator $toObjectId)
+(defoperator $toString)
+(defoperator $toLower)
+(defoperator $toUpper)
+(defoperator $trim)
+(defoperator $trunc)
+(defoperator $type)
+(defoperator $week)
+(defoperator $year)
+(defoperator $zip)
+
+;;; --- Query modifiers
+;;; https://docs.mongodb.com/manual/reference/operator/query-modifier/
+
+(defoperator $comment)
+(defoperator $explain)
+(defoperator $hint)
+(defoperator $max)
+(defoperator $maxTimeMS)
+(defoperator $min)
+(defoperator $orderby)
+(defoperator $query)
+(defoperator $returnKey)
+(defoperator $showDiskLoc)
+(defoperator $natural)
\ No newline at end of file