From NEOS

• CO - nonlinear programming in the GAUSS language.
• CONOPT - nonlinear programming.
• DONLP2 - nonlinear programming.
• DOT - Design Optimization Tools.
• Excel and Quattro Pro Solvers - spreadsheet-based linear, integer and nonlinear programming.
• FSQP - nonlinear and minmax constrained optimization, with feasible iterates.
• GINO - nonlinear programming.
• GRG2 - nonlinear programming.
• HARWELL Library - linear and nonlinear programming, nonlinear equations, data fitting.
• ILOG - constraint-based programming and nonlinear optimization.
• KNITRO -nonlinear programming..
• LANCELOT - large-scale problems.
• LINGO - linear, integer, nonlinear programming with modeling language.
• LOQO - Linear programming, unconstrained and constrained nonlinear optimization.
• LSGRG2 - nonlinear programming.
• MINOS - linear programming and nonlinear optimization.
• MOSEK - linear programming and convex nonlinear optimization.
• NLPJOB - Mulicriteria optimization.
• NLPQL - nonlinear programming.
• NLPQLB - nonlinear programming with constraints.
• NLPSPR - nonlinear programming.
• NPSOL - nonlinear programming.
• NOVA - nonlinear programming.
• OPTIMA Library - optimization and sensitivity analysis.
• PROC NLP - various nonlinear optimization capabilities.
• OPTPACK - constrained and unconstrained optimization.
• SNOPT - large-scale quadratic and nonlinear programming problems.
• SQP - nonlinear programming.
• SPRNLP - sparse and dense nonlinear programming.
• SYNAPS Pointer - multidiscplinary design optimization software.
• What's Best - Excel add-in for linear, integer, nonlinear programming.
• NLopt - a variety of nonlinear-constrained nonlinear optimization algorithms, including algorithms for large-scale problems

Software offering NLP Solvers

• AIMMS modeling system
• AMPL modeling language
• APMonitor modeling language
• GAMS modeling language
• LINGO modeling language
• Mosel modeling language
• MPL modeling system